Hard metal exposures. Part 1: Observed performance of three local exhaust ventilation systems.

PubMed

Guffey, S E; Simcox, N; Booth, D W; Hibbard, R; Stebbins, A

2000-04-01

Not every ventilation system performs as intended; much can be learned when they do not. The purpose of this study was to compare observed initial performance to expected levels for three saw-reconditioning shop ventilation systems and to characterize the changes in performance of the systems over a one-year period. These three local exhaust ventilation systems were intended to control worker exposures to cobalt, cadmium, and chromium during wet grinding, dry grinding, and welding/brazing activities. Prior to installation the authors provided some design guidance based on Industrial Ventilation, a Manual of Recommended Practice. However, the authors had limited influence on the actual installation and operation and no line authority for the systems. In apparent efforts to cut costs and to respond to other perceived needs, the installed systems deviated from the specifications used in pressure calculations in many important aspects, including adding branch ducts, use of flexible ducts, the choice of fans, and the construction of some hoods. After installation of the three systems, ventilation measurements were taken to determine if the systems met design specifications, and worker exposures were measured to determine effectiveness. The results of the latter will be published as a companion article. The deviations from design and maintenance failures may have adversely affected performance. From the beginning to the end of the study period the distribution of air flow never matched the design specifications for the systems. The observed air flows measured within the first month of installation did not match the predicated design air flows for any of the systems, probably because of the differences between the design and the installed system. Over the first year of operation, hood air flow variability was high due to inadequate cleaning of the sticky process materials which rapidly accumulated in the branch ducts. Poor distribution of air flows among branch ducts frequently produced individual hood air flows that were far below specified design levels even when the total air flow through that system was more than adequate. To experienced practitioners, it is not surprising that deviations from design recommendations and poor maintenance would be associated with poor system performance. Although commonplace, such experiences have not been documented in peer-reviewed publications to date. This publication is a first step in providing that documentation.

Development of an Outdoor Temperature-Based Control Algorithm for Residential Mechanical Ventilation Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Less, Brennan; Walker, Iain; Tang, Yihuan

2014-06-01

Smart ventilation systems use controls to ventilate more during those periods that provide either an energy or IAQ advantage (or both) and less during periods that provide a dis advantage. Using detailed building simulations, this study addresses one of the simplest and lowest cost types of smart controllers —outdoor temperature- based control. If the outdoor temperature falls below a certain cut- off, the fan is simply turned off. T he main principle of smart ventilation used in this study is to shift ventilation from time periods with large indoor -outdoor temperature differences, to periods where these differences are smaller, andmore » their energy impacts are expected to be less. Energy and IAQ performance are assessed relative to a base case of a continuously operated ventilation fan sized to comply with ASHRAE 62.2-2013 whole house ventilation requirements. In order to satisfy 62.2-2013, annual pollutant exposure must be equivalent between the temperature controlled and continuous fan cases. This requires ventilation to be greater than 62.2 requirements when the ventilation system operates. This is achieved by increasing the mechanical ventilation system air flow rates.« less

Development of Smart Ventilation Control Algorithms for Humidity Control in High-Performance Homes in Humid U.S. Climates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Less, Brennan; Walker, Iain; Ticci, Sara

Past field research and simulation studies have shown that high performance homes experience elevated indoor humidity levels for substantial portions of the year in humid climates. This is largely the result of lower sensible cooling loads, which reduces the moisture removed by the cooling system. These elevated humidity levels lead to concerns about occupant comfort, health and building durability. Use of mechanical ventilation at rates specified in ASHRAE Standard 62.2-2013 are often cited as an additional contributor to humidity problems in these homes. Past research has explored solutions, including supplemental dehumidification, cooling system operational enhancements and ventilation system design (e.g.,more » ERV, supply, exhaust, etc.). This project’s goal is to develop and demonstrate (through simulations) smart ventilation strategies that can contribute to humidity control in high performance homes. These strategies must maintain IAQ via equivalence with ASHRAE Standard 62.2-2013. To be acceptable they must not result in excessive energy use. Smart controls will be compared with dehumidifier energy and moisture performance. This work explores the development and performance of smart algorithms for control of mechanical ventilation systems, with the objective of reducing high humidity in modern high performance residences. Simulations of DOE Zero-Energy Ready homes were performed using the REGCAP simulation tool. Control strategies were developed and tested using the Residential Integrated Ventilation (RIVEC) controller, which tracks pollutant exposure in real-time and controls ventilation to provide an equivalent exposure on an annual basis to homes meeting ASHRAE 62.2-2013. RIVEC is used to increase or decrease the real-time ventilation rate to reduce moisture transport into the home or increase moisture removal. This approach was implemented for no-, one- and two-sensor strategies, paired with a variety of control approaches in six humid climates (Miami, Orlando, Houston, Charleston, Memphis and Baltimore). The control options were compared to a baseline system that supplies outdoor air to a central forced air cooling (and heating) system (CFIS) that is often used in hot humid climates. Simulations were performed with CFIS ventilation systems operating on a 33% duty-cycle, consistent with 62.2-2013. The CFIS outside airflow rates were set to 0%, 50% and 100% of 62.2-2013 requirements to explore effects of ventilation rate on indoor high humidity. These simulations were performed with and without a dehumidifier in the model. Ten control algorithms were developed and tested. Analysis of outdoor humidity patterns facilitated smart control development. It was found that outdoor humidity varies most strongly seasonally—by month of the year—and that all locations follow the similar pattern of much higher humidity during summer. Daily and hourly variations in outdoor humidity were found to be progressively smaller than the monthly seasonal variation. Patterns in hourly humidity are driven by diurnal daily patterns, so they were predictable but small, and were unlikely to provide much control benefit. Variation in outdoor humidity between days was larger, but unpredictable, except by much more complex climate models. We determined that no-sensor strategies might be able to take advantage of seasonal patterns in humidity, but that real-time smart controls were required to capture variation between days. Sensor-based approaches are also required to respond dynamically to indoor conditions and variations not considered in our analysis. All smart controls face trade-offs between sensor accuracy, cost, complexity and robustness.« less

Test Protocol for Room-to-Room Distribution of Outside Air by Residential Ventilation Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barley, C. D.; Anderson, R.; Hendron, B.

2007-12-01

This test and analysis protocol has been developed as a practical approach for measuring outside air distribution in homes. It has been used successfully in field tests and has led to significant insights on ventilation design issues. Performance advantages of more sophisticated ventilation systems over simpler, less-costly designs have been verified, and specific problems, such as airflow short-circuiting, have been identified.

Electrosurgical Smoke: Ultrafine Particle Measurements and Work Environment Quality in Different Operating Theatres

PubMed Central

Romano, Francesco; Gustén, Jan; De Antonellis, Stefano; Joppolo, Cesare M.

2017-01-01

Air cleanliness in operating theatres (OTs) is an important factor for preserving the health of both the patient and the medical staff. Particle contamination in OTs depends mainly on the surgery process, ventilation principle, personnel clothing systems and working routines. In many open surgical operations, electrosurgical tools (ESTs) are used for tissue cauterization. ESTs generate a significant airborne contamination, as surgical smoke. Surgical smoke is a work environment quality problem. Ordinary surgical masks and OT ventilation systems are inadequate to control this problem. This research work is based on numerous monitoring campaigns of ultrafine particle concentrations in OTs, equipped with upward displacement ventilation or with a downward unidirectional airflow system. Measurements performed during ten real surgeries highlight that the use of ESTs generates a quite sharp and relevant increase of particle concentration in the surgical area as well within the entire OT area. The measured contamination level in the OTs are linked to surgical operation, ventilation principle, and ESTs used. A better knowledge of airborne contamination is crucial for limiting the personnel’s exposure to surgical smoke. Research results highlight that downward unidirectional OTs can give better conditions for adequate ventilation and contaminant removal performances than OTs equipped with upward displacement ventilation systems. PMID:28146089

The ventilation problem in schools: literature review

DOE PAGES

Fisk, W. J.

2017-07-06

Based on a review of literature published in refereed archival journals, ventilation rates in classrooms often fall far short of the minimum ventilation rates specified in standards. We report that there is compelling evidence, from both cross-sectional and intervention studies, of an association of increased student performance with increased ventilation rates. There is evidence that reduced respiratory health effects and reduced student absence are associated with increased ventilation rates. Increasing ventilation rates in schools imposes energy costs and can increase heating, ventilating, and air-conditioning system capital costs. The net annual costs, ranging from a few dollars to about 10 dollarsmore » per person, are less than 0.1% of typical public spending on elementary and secondary education in the United States. Finally, such expenditures seem like a small price to pay given the evidence of health and performance benefits.« less

The ventilation problem in schools: literature review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fisk, W. J.

Based on a review of literature published in refereed archival journals, ventilation rates in classrooms often fall far short of the minimum ventilation rates specified in standards. We report that there is compelling evidence, from both cross-sectional and intervention studies, of an association of increased student performance with increased ventilation rates. There is evidence that reduced respiratory health effects and reduced student absence are associated with increased ventilation rates. Increasing ventilation rates in schools imposes energy costs and can increase heating, ventilating, and air-conditioning system capital costs. The net annual costs, ranging from a few dollars to about 10 dollarsmore » per person, are less than 0.1% of typical public spending on elementary and secondary education in the United States. Finally, such expenditures seem like a small price to pay given the evidence of health and performance benefits.« less

Mine fire experiments and simulation with MFIRE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laage, L.W.; Yang, Hang

1995-12-31

A major concern of mine fires is the heat generated ventilation disturbances which can move products of combustion (POC) through unexpected passageways. Fire emergency planning requires simulation of the interaction of the fire and ventilation system to predict the state of the ventilation system and the subsequent distribution of temperatures and POC. Several computer models were developed by the U.S. Bureau of Mines (USBM) to perform this simulation. The most recent, MFIRE, simulates a mine`s ventilation system and its response to altered ventilation parameters such as the development of new mine workings or changes in ventilation control structures, external influencemore » such as varying outside temperatures, and internal influences such as fires. Extensive output allows quantitative analysis of the effects of the proposed alteration to die ventilation system. This paper describes recent USBM research to validate MFIRE`s calculation of temperature distribution in an airway due to a mine fire, as temperatures are the most significant source of ventilation disturbances. Fire tests were conducted at the Waldo Mine near Magdalena, NM. From these experiments, temperature profiles were developed as functions of time and distance from the fire and compared with simulations from MFIRE.« less

Surgical clothing systems in laminar airflow operating room: a numerical assessment.

PubMed

Sadrizadeh, Sasan; Holmberg, Sture

2014-01-01

This study compared two different laminar airflow distribution strategies - horizontal and vertical - and investigated the effectiveness of both ventilation systems in terms of reducing the sedimentation and distribution of bacteria-carrying particles. Three different staff clothing systems, which resulted in source strengths of 1.5, 4 and 5 CFU/s per person, were considered. The exploration was conducted numerically using a computational fluid dynamics technique. Active and passive air sampling methods were simulated in addition to recovery tests, and the results were compared. Model validation was performed through comparisons with measurement data from the published literature. The recovery test yielded a value of 8.1 min for the horizontal ventilation scenario and 11.9 min for the vertical ventilation system. Fewer particles were captured by the slit sampler and in sedimentation areas with the horizontal ventilation system. The simulated results revealed that under identical conditions in the examined operating room, the horizontal laminar ventilation system performed better than the vertical option. The internal constellation of lamps, the surgical team and objects could have a serious effect on the movement of infectious particles and therefore on postoperative surgical site infections. Copyright © 2014 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

Integration of a photocatalytic multi-tube reactor for indoor air purification in HVAC systems: a feasibility study.

PubMed

van Walsem, Jeroen; Roegiers, Jelle; Modde, Bart; Lenaerts, Silvia; Denys, Siegfried

2018-04-24

This work is focused on an in-depth experimental characterization of multi-tube reactors for indoor air purification integrated in ventilation systems. Glass tubes were selected as an excellent photocatalyst substrate to meet the challenging requirements of the operating conditions in a ventilation system in which high flow rates are typical. Glass tubes show a low-pressure drop which reduces the energy demand of the ventilator, and additionally, they provide a large exposed surface area to allow interaction between indoor air contaminants and the photocatalyst. Furthermore, the performance of a range of P25-loaded sol-gel coatings was investigated, based on their adhesion properties and photocatalytic activities. Moreover, the UV light transmission and photocatalytic reactor performance under various operating conditions were studied. These results provide vital insights for the further development and scaling up of multi-tube reactors in ventilation systems which can provide a better comfort, improved air quality in indoor environments, and reduced human exposure to harmful pollutants.

A Systems Approach to High Performance Buildings: A Computational Systems Engineering R&D Program to Increase DoD Energy Efficiency

DTIC Science & Technology

2012-02-01

for Low Energy Building Ventilation and Space Conditioning Systems...Building Energy Models ................... 162 APPENDIX D: Reduced-Order Modeling and Control Design for Low Energy Building Systems .... 172 D.1...Design for Low Energy Building Ventilation and Space Conditioning Systems This section focuses on the modeling and control of airflow in buildings

International Space Station USOS Crew Quarters Ventilation and Acoustic Design Implementation

NASA Technical Reports Server (NTRS)

Broyan, James Lee, Jr.

2009-01-01

The International Space Station (ISS) United States Operational Segment (USOS) has four permanent rack sized ISS Crew Quarters (CQ) providing a private crewmember space. The CQ uses Node 2 cabin air for ventilation/thermal cooling, as opposed to conditioned ducted air from the ISS Temperature Humidity Control System or the ISS fluid cooling loop connections. Consequently, CQ can only increase the air flow rate to reduce the temperature delta between the cabin and the CQ interior. However, increasing airflow causes increased acoustic noise so efficient airflow distribution is an important design parameter. The CQ utilized a two fan push-pull configuration to ensure fresh air at the crewmember s head position and reduce acoustic exposure. The CQ interior needs to be below Noise Curve 40 (NC-40). The CQ ventilation ducts are open to the significantly louder Node 2 cabin aisle way which required significantly acoustic mitigation controls. The design implementation of the CQ ventilation system and acoustic mitigation are very inter-related and require consideration of crew comfort balanced with use of interior habitable volume, accommodation of fan failures, and possible crew uses that impact ventilation and acoustic performance. This paper illustrates the types of model analysis, assumptions, vehicle interactions, and trade-offs required for CQ ventilation and acoustics. Additionally, on-orbit ventilation system performance and initial crew feedback is presented. This approach is applicable to any private enclosed space that the crew will occupy.

Antibiotic therapy in ventilator-associated tracheobronchitis: a literature review.

PubMed

Alves, Abel Eduardo; Pereira, José Manuel

2018-03-01

The concept of ventilator-associated tracheobronchitis is controversial; its definition is not unanimously accepted and often overlaps with ventilator-associated pneumonia. Ventilator-associated tracheobronchitis has an incidence similar to that of ventilator-associated pneumonia, with a high prevalence of isolated multiresistant agents, resulting in an increase in the time of mechanical ventilation and hospitalization but without an impact on mortality. The performance of quantitative cultures may allow better diagnostic definition of tracheobronchitis associated with mechanical ventilation, possibly avoiding the overdiagnosis of this condition. One of the major difficulties in differentiating between ventilator-associated tracheobronchitis and ventilator-associated pneumonia is the exclusion of a pulmonary infiltrate by chest radiography; thoracic computed tomography, thoracic ultrasonography, or invasive specimen collection may also be required. The institution of systemic antibiotic therapy does not improve the clinical impact of ventilator-associated tracheobronchitis, particularly in reducing time of mechanical ventilation, hospitalization or mortality, despite the possible reduced progression to ventilator-associated pneumonia. However, there are doubts regarding the methodology used. Thus, considering the high prevalence of tracheobronchitis associated with mechanical ventilation, routine treatment of this condition would result in high antibiotic usage without clear benefits. However, we suggest the institution of antibiotic therapy in patients with tracheobronchitis associated with mechanical ventilation and septic shock and/or worsening of oxygenation, and other auxiliary diagnostic tests should be simultaneously performed to exclude ventilator-associated pneumonia. This review provides a better understanding of the differentiation between tracheobronchitis associated with mechanical ventilation and pneumonia associated with mechanical ventilation, which can significantly decrease the use of antibiotics in critically ventilated patients.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maxwell, S.; Berger, D.; Zuluaga, M.

In multifamily buildings, particularly in the Northeast, exhaust ventilation strategies are the norm as a means of meeting both local exhaust and whole-unit mechanical ventilation rates. The issue of where the "fresh" air is coming from is gaining significance as air-tightness standards for enclosures become more stringent. CARB researchers have found that most new high performance, multifamily housing in the Northeast use one of four strategies for ventilation: continuous exhaust only with no designated supply or make-up air source, continuous exhaust with ducted make-up air to apartments, continuous exhaust with supply through a make-up air device integral to the unitmore » HVAC, and continuous exhaust with supply through a passive inlet device, such as a trickle vent. Insufficient information is available to designers on how these various systems are best applied. Product performance data are based on laboratory tests, but there is no guarantee that those conditions will exist consistently in the finished building. In this research project, CARB evaluated the four ventilation strategies in the field to validate system performance.« less

Short-term airing by natural ventilation - modeling and control strategies.

PubMed

Perino, M; Heiselberg, P

2009-10-01

The need to improve the energy efficiency of buildings requires new and more efficient ventilation systems. It has been demonstrated that innovative operating concepts that make use of natural ventilation seem to be more appreciated by occupants. This kind of system frequently integrates traditional mechanical ventilation components with natural ventilation devices, such as motorized windows and louvers. Among the various ventilation strategies that are currently available, buoyancy driven single-sided natural ventilation has proved to be very effective and can provide high air change rates for temperature and IAQ control. However, in order to promote a wider applications of these systems, an improvement in the knowledge of their working principles and the availability of new design and simulation tools is necessary. In this context, the paper analyses and presents the results of a research that was aimed at developing and validating numerical models for the analysis of buoyancy driven single-sided natural ventilation systems. Once validated, these models can be used to optimize control strategies in order to achieve satisfactory indoor comfort conditions and IAQ. Practical Implications Numerical and experimental analyses have proved that short-term airing by intermittent ventilation is an effective measure to satisfactorily control IAQ. Different control strategies have been investigated to optimize the capabilities of the systems. The proposed zonal model has provided good performances and could be adopted as a design tool, while CFD simulations can be profitably used for detailed studies of the pollutant concentration distribution in a room and to address local discomfort problems.

Energy and cost associated with ventilating office buildings in a tropical climate.

PubMed

Rim, Donghyun; Schiavon, Stefano; Nazaroff, William W

2015-01-01

Providing sufficient amounts of outdoor air to occupants is a critical building function for supporting occupant health, well-being and productivity. In tropical climates, high ventilation rates require substantial amounts of energy to cool and dehumidify supply air. This study evaluates the energy consumption and associated cost for thermally conditioning outdoor air provided for building ventilation in tropical climates, considering Singapore as an example locale. We investigated the influence on energy consumption and cost of the following factors: outdoor air temperature and humidity, ventilation rate (L/s per person), indoor air temperature and humidity, air conditioning system coefficient of performance (COP), and cost of electricity. Results show that dehumidification of outdoor air accounts for more than 80% of the energy needed for building ventilation in Singapore's tropical climate. Improved system performance and/or a small increase in the indoor temperature set point would permit relatively large ventilation rates (such as 25 L/s per person) at modest or no cost increment. Overall, even in a thermally demanding tropical climate, the energy cost associated with increasing ventilation rate up to 25 L/s per person is less than 1% of the wages of an office worker in an advanced economy like Singapore's. This result implies that the benefits of increasing outdoor air ventilation rate up to 25 L/s per person--which is suggested to provide for productivity increases, lower sick building syndrome symptom prevalence, and reduced sick leave--can be much larger than the incremental cost of ventilation.

Small scale power generation from biomass-technical potential

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lepori, W.A.; Cardenas, M.M.; Carney, O.B.

1983-12-01

System and nursery pig performance data for the Winter of 1983 were collected for a 96-pig capacity modified-open-front (MOF) naturally ventilated and a 96-pig capacity mechanically ventilated swine nurseries. Both nurseries utilized active solar collectors to provide in-floor heating at the rear of each pen along with hovers. The mechanically ventilated nursery utilized solar preheated ventilation air. The naturally ventilated nursery had double glazed solar windows to passively heat the interior space. The relative humidity in the naturally ventilated (NV) nursery averaged 20 percentage points higher than the mechanically ventilated (MV) nursery with no significant differences in air temperature. Themore » MV nursery used 50% more energy than the NV nursery and the NV nursery required 1.9 kWh/pig marketed less than that needed for the MV nursery. Pig performance figure were not significantly different between the two buildings. The feed to gain ration were 2.0 + or - 0.35 and 1.96 + or 0.38 for the MV and NV nurseries respectively.« less

Associations between classroom CO2 concentrations and student attendance in Washington and Idaho.

PubMed

Shendell, D G; Prill, R; Fisk, W J; Apte, M G; Blake, D; Faulkner, D

2004-10-01

Student attendance in American public schools is a critical factor in securing limited operational funding. Student and teacher attendance influence academic performance. Limited data exist on indoor air and environmental quality (IEQ) in schools, and how IEQ affects attendance, health, or performance. This study explored the association of student absence with measures of indoor minus outdoor carbon dioxide concentration (dCO(2)). Absence and dCO(2) data were collected from 409 traditional and 25 portable classrooms from 22 schools located in six school districts in the states of Washington and Idaho. Study classrooms had individual heating, ventilation, and air conditioning (HVAC) systems, except two classrooms without mechanical ventilation. Classroom attributes, student attendance and school-level ethnicity, gender, and socioeconomic status (SES) were included in multivariate modeling. Forty-five percent of classrooms studied had short-term indoor CO(2) concentrations above 1000 p.p.m. A 1000 p.p.m. increase in dCO(2) was associated (P < 0.05) with a 0.5-0.9% decrease in annual average daily attendance (ADA), corresponding to a relative 10-20% increase in student absence. Annual ADA was 2% higher (P < 0.0001) in traditional than in portable classrooms. This study provides motivation for larger school studies to investigate associations of student attendance, and occupant health and student performance, with longer term indoor minus outdoor CO(2) concentrations and more accurately measured ventilation rates. If our findings are confirmed, improving classroom ventilation should be considered a practical means of reducing student absence. Adequate or enhanced ventilation may be achieved, for example, with educational training programs for teachers and facilities staff on ventilation system operation and maintenance. Also, technological interventions such as improved automated control systems could provide continuous ventilation during occupied times, regardless of occupant thermal comfort demands.

Results from Carbon Dioxide Washout Testing Using a Suited Manikin Test Apparatus with a Space Suit Ventilation Test Loop

NASA Technical Reports Server (NTRS)

Chullen, Cinda; Conger, Bruce; McMillin, Summer; Vonau, Walt; Kanne, Bryan; Korona, Adam; Swickrath, Mike

2016-01-01

NASA is developing an advanced portable life support system (PLSS) to meet the needs of a new NASA advanced space suit. The PLSS is one of the most critical aspects of the space suit providing the necessary oxygen, ventilation, and thermal protection for an astronaut performing a spacewalk. The ventilation subsystem in the PLSS must provide sufficient carbon dioxide (CO2) removal and ensure that the CO2 is washed away from the oronasal region of the astronaut. CO2 washout is a term used to describe the mechanism by which CO2 levels are controlled within the helmet to limit the concentration of CO2 inhaled by the astronaut. Accumulation of CO2 in the helmet or throughout the ventilation loop could cause the suited astronaut to experience hypercapnia (excessive carbon dioxide in the blood). A suited manikin test apparatus (SMTA) integrated with a space suit ventilation test loop was designed, developed, and assembled at NASA in order to experimentally validate adequate CO2 removal throughout the PLSS ventilation subsystem and to quantify CO2 washout performance under various conditions. The test results from this integrated system will be used to validate analytical models and augment human testing. This paper presents the system integration of the PLSS ventilation test loop with the SMTA including the newly developed regenerative Rapid Cycle Amine component used for CO2 removal and tidal breathing capability to emulate the human. The testing and analytical results of the integrated system are presented along with future work.

Using Coupled Energy, Airflow and IAQ Software (TRNSYS/CONTAM) to Evaluate Building Ventilation Strategies.

PubMed

Dols, W Stuart; Emmerich, Steven J; Polidoro, Brian J

2016-03-01

Building energy analysis tools are available in many forms that provide the ability to address a broad spectrum of energy-related issues in various combinations. Often these tools operate in isolation from one another, making it difficult to evaluate the interactions between related phenomena and interacting systems, forcing oversimplified assumptions to be made about various phenomena that could otherwise be addressed directly with another tool. One example of such interdependence is the interaction between heat transfer, inter-zone airflow and indoor contaminant transport. In order to better address these interdependencies, the National Institute of Standards and Technology (NIST) has developed an updated version of the multi-zone airflow and contaminant transport modelling tool, CONTAM, along with a set of utilities to enable coupling of the full CONTAM model with the TRNSYS simulation tool in a more seamless manner and with additional capabilities that were previously not available. This paper provides an overview of these new capabilities and applies them to simulating a medium-size office building. These simulations address the interaction between whole-building energy, airflow and contaminant transport in evaluating various ventilation strategies including natural and demand-controlled ventilation. CONTAM has been in practical use for many years allowing building designers, as well as IAQ and ventilation system analysts, to simulate the complex interactions between building physical layout and HVAC system configuration in determining building airflow and contaminant transport. It has been widely used to design and analyse smoke management systems and evaluate building performance in response to chemical, biological and radiological events. While CONTAM has been used to address design and performance of buildings implementing energy conserving ventilation systems, e.g., natural and hybrid, this new coupled simulation capability will enable users to apply the tool to couple CONTAM with existing energy analysis software to address the interaction between indoor air quality considerations and energy conservation measures in building design and analysis. This paper presents two practical case studies using the coupled modelling tool to evaluate IAQ performance of a CO 2 -based demand-controlled ventilation system under different levels of building envelope airtightness and the design and analysis of a natural ventilation system.

Using Coupled Energy, Airflow and IAQ Software (TRNSYS/CONTAM) to Evaluate Building Ventilation Strategies

PubMed Central

Dols, W. Stuart.; Emmerich, Steven J.; Polidoro, Brian J.

2016-01-01

Building energy analysis tools are available in many forms that provide the ability to address a broad spectrum of energy-related issues in various combinations. Often these tools operate in isolation from one another, making it difficult to evaluate the interactions between related phenomena and interacting systems, forcing oversimplified assumptions to be made about various phenomena that could otherwise be addressed directly with another tool. One example of such interdependence is the interaction between heat transfer, inter-zone airflow and indoor contaminant transport. In order to better address these interdependencies, the National Institute of Standards and Technology (NIST) has developed an updated version of the multi-zone airflow and contaminant transport modelling tool, CONTAM, along with a set of utilities to enable coupling of the full CONTAM model with the TRNSYS simulation tool in a more seamless manner and with additional capabilities that were previously not available. This paper provides an overview of these new capabilities and applies them to simulating a medium-size office building. These simulations address the interaction between whole-building energy, airflow and contaminant transport in evaluating various ventilation strategies including natural and demand-controlled ventilation. Practical Application CONTAM has been in practical use for many years allowing building designers, as well as IAQ and ventilation system analysts, to simulate the complex interactions between building physical layout and HVAC system configuration in determining building airflow and contaminant transport. It has been widely used to design and analyse smoke management systems and evaluate building performance in response to chemical, biological and radiological events. While CONTAM has been used to address design and performance of buildings implementing energy conserving ventilation systems, e.g., natural and hybrid, this new coupled simulation capability will enable users to apply the tool to couple CONTAM with existing energy analysis software to address the interaction between indoor air quality considerations and energy conservation measures in building design and analysis. This paper presents two practical case studies using the coupled modelling tool to evaluate IAQ performance of a CO2-based demand-controlled ventilation system under different levels of building envelope airtightness and the design and analysis of a natural ventilation system. PMID:27099405

Ventilator-Related Adverse Events: A Taxonomy and Findings From 3 Incident Reporting Systems.

PubMed

Pham, Julius Cuong; Williams, Tamara L; Sparnon, Erin M; Cillie, Tam K; Scharen, Hilda F; Marella, William M

2016-05-01

In 2009, researchers from Johns Hopkins University's Armstrong Institute for Patient Safety and Quality; public agencies, including the FDA; and private partners, including the Emergency Care Research Institute and the University HealthSystem Consortium (UHC) Safety Intelligence Patient Safety Organization, sought to form a public-private partnership for the promotion of patient safety (P5S) to advance patient safety through voluntary partnerships. The study objective was to test the concept of the P5S to advance our understanding of safety issues related to ventilator events, to develop a common classification system for categorizing adverse events related to mechanical ventilators, and to perform a comparison of adverse events across different adverse event reporting systems. We performed a cross-sectional analysis of ventilator-related adverse events reported in 2012 from the following incident reporting systems: the Pennsylvania Patient Safety Authority's Patient Safety Reporting System, UHC's Safety Intelligence Patient Safety Organization database, and the FDA's Manufacturer and User Facility Device Experience database. Once each organization had its dataset of ventilator-related adverse events, reviewers read the narrative descriptions of each event and classified it according to the developed common taxonomy. A Pennsylvania Patient Safety Authority, FDA, and UHC search provided 252, 274, and 700 relevant reports, respectively. The 3 event types most commonly reported to the UHC and the Pennsylvania Patient Safety Authority's Patient Safety Reporting System databases were airway/breathing circuit issue, human factor issues, and ventilator malfunction events. The top 3 event types reported to the FDA were ventilator malfunction, power source issue, and alarm failure. Overall, we found that (1) through the development of a common taxonomy, adverse events from 3 reporting systems can be evaluated, (2) the types of events reported in each database were related to the purpose of the database and the source of the reports, resulting in significant differences in reported event categories across the 3 systems, and (3) a public-private collaboration for investigating ventilator-related adverse events under the P5S model is feasible. Copyright © 2016 by Daedalus Enterprises.

The effect of closed system suction on airway pressures when using the Servo 300 ventilator.

PubMed

Frengley, R W; Closey, D N; Sleigh, J W; Torrance, J M

2001-12-01

To measure airway pressures during closed system suctioning with the ventilator set to three differing modes of ventilation. Closed system suctioning was conducted in 16 patients following cardiac surgery. Suctioning was performed using a 14 French catheter with a vacuum level of -500 cmH2O through an 8.0 mm internal diameter endotracheal tube. The lungs were mechanically ventilated with a Servo 300 ventilator set to one of three ventilation modes: volume-control, pressure-control or CPAP/pressure support. Airway pressures were measured via a 4 French electronic pressure transducer in both proximal and distal airways. Following insertion of the suction catheter, end-expiratory pressure increased significantly (p < 0.001) in both pressure-control and volume-control ventilation. This increase was greatest (p = 0.018) in volume-control mode (2.7 +/- 1.7 cmH2O). On performing a five second suction, airway pressure decreased in all modes, however the lowest airway pressure in volume-control mode (-4.9 +/- 4.0 cmH2O) was significantly (p = 0.001) less than the lowest airway pressure recorded in either pressure-control (0.8 +/- 1.9 cmH2O) or CPAP/pressure support (0.4 +/- 2.8 cmH2O) modes. In CPAP/pressure support mode, 13 of the 16 patients experienced a positive pressure 'breath' at the end of suctioning with airway pressures rising to 21 +/- 1.6 cmH2O. Closed system suctioning in volume control ventilation may result in elevations of end-expiratory pressure following catheter insertion and subatmospheric airway pressures during suctioning. Pressure control ventilation produces less elevation of end-expiratory pressure following catheter insertion and is less likely to be associated with subatmospheric airway pressures during suctioning. CPAP/pressure support has no effect on end-expiratory pressure following catheter insertion and subatmospheric airway pressures are largely avoided during suctioning.

Reducing the ingress of urban noise through natural ventilation openings.

PubMed

Oldham, D J; de Salis, M H; Sharples, S

2004-01-01

For buildings in busy urban areas affected by high levels of road traffic noise the potential to use natural ventilation can be limited by excessive noise entering through ventilation openings. This paper is concerned with techniques to reduce noise ingress into naturally ventilated buildings while minimizing airflow path resistance. A combined experimental and theoretical approach to the interaction of airflow and sound transmission through ventilators for natural ventilation applications is described. A key element of the investigation has been the development of testing facilities capable of measuring the airflow and sound transmission losses for a range of ventilation noise control strategies. It is demonstrated that a combination of sound reduction mechanisms -- one covering low frequency sound and another covering high frequency sound -- is required to attenuate effectively noise from typical urban sources. A method is proposed for quantifying the acoustic performance of different strategies to enable comparisons and informed decisions to be made leading to the possibility of a design methodology for optimizing the ventilation and acoustic performance of different strategies. The need for employing techniques for combating low frequency sound in tandem with techniques for reducing high frequency sound in reducing the ingress of noise from urban sources such as road traffic to acceptable levels is demonstrated. A technique is proposed for enabling the acoustic and airflow performance of apertures for natural ventilation systems to be designed simultaneously.

Comparison of freezing control strategies for residential air-to-air heat recovery ventilators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, E.G.; Bradley, L.C.; Chant, R.E.

1989-01-01

A comparison of the energy performance of defrost and frost control strategies for residential air-to-air heat recovery ventilators (HRV) has been carried out by using computer simulations for various climatic conditions. This paper discusses the results and conclusions from the comparisons and their implications for the heat recovery ventilator manufacturers and system designers.

Humidifier Development and Applicability to the Next Generation Portable Life Support System

NASA Technical Reports Server (NTRS)

Conger, Bruce C.; Barnes, Bruce G.; Sompayrac, Robert G.; Paul, Heather L.

2011-01-01

A development effort at the NASA Johnson Space Center investigated technologies to determine whether a humidifier would be required in the Portable Life Support System (PLSS) envisioned for future exploration missions. The humidifier has been included in the baseline PLSS schematic since performance testing of the Rapid Cycle Amine (RCA) indicates that the RCA over-dries the ventilation gas stream. Performance tests of a developmental humidifier unit and commercial off-the-shelf (COTS) units were conducted in December 2009. Following these tests, NASA revisited the need for a humidifier via system analysis. Results of this investigation indicate that it is feasible to meet humidity requirements without the humidifier if other changes are made to the PLSS ventilation loop and the Liquid Cooling and Ventilation Garment (LCVG).

Ventilation noise and its effects on annoyance and performance

NASA Astrophysics Data System (ADS)

Landstrom, Ulf

2004-05-01

In almost every room environment, ventilation acts as a more or less prominent part of the noise exposure. The contribution to the overall sound environment is a question not only of the way in which the ventilation system itself functions, but also a question of the prominence of other contemporary sound sources such as speech, equipment, machines, and external noises. Hazardous effects due to ventilation noise are most prominent in offices, hospitals, control rooms, classrooms, conference rooms, and other types of silent areas. The effects evoked by ventilation noise have also been found to be related to the type of activity being conducted. Annoyance and performance thus not only seemed to be linked to the physical character of exposure, i.e., noise level, frequency characteristics, and length of exposure, but also mental and manual activity, complexity, and monotony of the work. The effects can be described in terms of annoyance, discomfort, and fatigue, with consequences on performance and increased mental load. The silent areas where ventilation noise may be most frequently experienced are often synonymous with areas and activities most sensitive to the exposure.

AIR CLEANING FOR ACCEPTABLE INDOOR AIR QUALITY

EPA Science Inventory

The paper discusses air cleaning for acceptable indoor air quality. ir cleaning has performed an important role in heating, ventilation, and air-conditioning systems for many years. raditionally, general ventilation air-filtration equipment has been used to protect cooling coils ...

Evaluation of ventilators used during transport of critically ill patients: a bench study.

PubMed

Boussen, Salah; Gainnier, Marc; Michelet, Pierre

2013-11-01

To evaluate the most recent transport ventilators' operational performance regarding volume delivery in controlled mode, trigger function, and the quality of pressurization in pressure support mode. Eight recent transport ventilators were included in a bench study in order to evaluate their accuracy to deliver a set tidal volume under normal resistance and compliance conditions, ARDS conditions, and obstructive conditions. The performance of the triggering system was assessed by the measure of the decrease in pressure and the time delay required to open the inspiratory valve. The quality of pressurization was obtained by computing the integral of the pressure-time curve for the first 300 ms and 500 ms after the onset of inspiration. For the targeted tidal volumes of 300, 500, and 800 mL the errors ranged from -3% to 48%, -7% to 18%, and -5% to 25% in the normal conditions, -4% to 27%, -2% to 35%, and -3% to 35% in the ARDS conditions, and -4% to 53%, -6% to 30%, and -30% to 28% in the obstructive conditions. In pressure support mode the pressure drop range was 0.4-1.7 cm H2O, the trigger delay range was 68-198 ms, and the pressurization performance (percent of ideal pressurization, as measured by pressure-time product at 300 ms and 500 ms) ranges were -9% to 44% at 300 ms and 6%-66% at 500 ms (P < .01). There were important differences in the performance of the tested ventilators. The most recent turbine ventilators outperformed the pneumatic ventilators. The best performers among the turbine ventilators proved comparable to modern ICU ventilators.

Energy and Cost Associated with Ventilating Office Buildings in a Tropical Climate

PubMed Central

Rim, Donghyun; Schiavon, Stefano; Nazaroff, William W.

2015-01-01

Providing sufficient amounts of outdoor air to occupants is a critical building function for supporting occupant health, well-being and productivity. In tropical climates, high ventilation rates require substantial amounts of energy to cool and dehumidify supply air. This study evaluates the energy consumption and associated cost for thermally conditioning outdoor air provided for building ventilation in tropical climates, considering Singapore as an example locale. We investigated the influence on energy consumption and cost of the following factors: outdoor air temperature and humidity, ventilation rate (L/s per person), indoor air temperature and humidity, air conditioning system coefficient of performance (COP), and cost of electricity. Results show that dehumidification of outdoor air accounts for more than 80% of the energy needed for building ventilation in Singapore’s tropical climate. Improved system performance and/or a small increase in the indoor temperature set point would permit relatively large ventilation rates (such as 25 L/s per person) at modest or no cost increment. Overall, even in a thermally demanding tropical climate, the energy cost associated with increasing ventilation rate up to 25 L/s per person is less than 1% of the wages of an office worker in an advanced economy like Singapore’s. This result implies that the benefits of increasing outdoor air ventilation rate up to 25 L/s per person — which is suggested to provide for productivity increases, lower sick building syndrome symptom prevalence, and reduced sick leave — can be much larger than the incremental cost of ventilation. PMID:25822504

Summary of human responses to ventilation.

PubMed

Seppänen, O A; Fisk, W J

2004-01-01

It is known that ventilation is necessary to remove indoor-generated pollutants from indoor air or dilute their concentration to acceptable levels. But as the limit values of all pollutants are not known the exact determination of required ventilation rates based on pollutant concentrations is seldom possible. The selection of ventilation rates has to be based also on epidemiological research, laboratory and field experiments and experience. The existing literature indicates that ventilation has a significant impact on several important human outcomes including: (1) communicable respiratory illnesses; (2) sick building syndrome symptoms; (3) task performance and productivity, and (4) perceived air quality (PAQ) among occupants or sensory panels (5) respiratory allergies and asthma. In many studies, prevalence of sick building syndrome symptoms has also been associated with characteristics of HVAC-systems. Often the prevalence of SBS symptoms is higher in air-conditioned buildings than in naturally ventilated buildings. The evidence suggests that better hygiene, commissioning, operation and maintenance of air handling systems may be particularly important for reducing the negative effects of HVAC systems. Ventilation may also have harmful effects on indoor air quality and climate if not properly designed, installed, maintained and operated. Ventilation may bring indoors harmful substances or deteriorate indoor environment. Ventilation interacts also with the building envelope and may deteriorate the structures of the building. Ventilation changes the pressure differences across the structures of building and may cause or prevent infiltration of pollutants from structures or adjacent spaces. Ventilation is also in many cases used to control the thermal environment or humidity in buildings. The paper summarises the current knowledge on positive and negative effects of ventilation on health and other human responses. The focus is on office-type working environment and residential buildings. The review shows that ventilation has various positive impacts on health and productivity of building occupants. Ventilation reduces the prevalence of airborne infectious diseases and thus the number of sick leave days. In office environment a ventilation rate up to 20-25 L/s per person seem to decrease the prevalence of SBS-symptoms. Air conditioning systems may increase the prevalence of SBS-symptoms relative to natural ventilation if not clean. In residential buildings the air change rate in cold climates should not be below app. 0.5 ach. Ventilation systems may cause pressure differences over the building envelope and bring harmful pollutants indoors.

A concept of external aerodynamic elements in improving the performance of natural smoke ventilation in wind conditions

NASA Astrophysics Data System (ADS)

Wegrzyński, Wojciech; Krajewski, Grzegorz; Kimbar, Grzegorz

2018-01-01

This paper is a proposal of a new device that may be used as a component of natural smoke ventilation systems - an external aerodynamic baffle used to limit the wind effect at the most adverse angle. Natural ventilation is not only affected by the external wind, but also dependent on the angle of wind attack. It has been proven, that at angles between 45° to 60° the performance of such device is the lowest. This is the reason why additional device is proposed - external baffle that could hypothetically increase the performance at chosen angles. The purpose of this paper is to explore this idea by numerical modelling of such external elements on a validated natural ventilator model, with use of ANSYS® Fluent® CFD model.

WASTE HANDLING BUILDING VENTILATION SYSTEM DESCRIPTION DOCUMENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

P.A. Kumar

2000-06-21

The Waste Handling Building Ventilation System provides heating, ventilation, and air conditioning (HVAC) for the contaminated, potentially contaminated, and uncontaminated areas of the Monitored Geologic Repository's (MGR) Waste Handling Building (WHB). In the uncontaminated areas, the non-confinement area ventilation system maintains the proper environmental conditions for equipment operation and personnel comfort. In the contaminated and potentially contaminated areas, in addition to maintaining the proper environmental conditions for equipment operation and personnel comfort, the contamination confinement area ventilation system directs potentially contaminated air away from personnel in the WHB and confines the contamination within high-efficiency particulate air (HEPA) filtration units. Themore » contamination confinement areas ventilation system creates airflow paths and pressure zones to minimize the potential for spreading contamination within the building. The contamination confinement ventilation system also protects the environment and the public by limiting airborne releases of radioactive or other hazardous contaminants from the WHB. The Waste Handling Building Ventilation System is designed to perform its safety functions under accident conditions and other Design Basis Events (DBEs) (such as earthquakes, tornadoes, fires, and loss of the primary electric power). Additional system design features (such as compartmentalization with independent subsystems) limit the potential for cross-contamination within the WHB. The system provides status of important system parameters and equipment operation, and provides audible and/or visual indication of off-normal conditions and equipment failures. The Waste Handling Building Ventilation System confines the radioactive and hazardous material within the building such that the release rates comply with regulatory limits. The system design, operations, and maintenance activities incorporate ALARA (as low as is reasonably achievable) principles to maintain personnel radiation doses to all occupational workers below regulatory limits and as low as is reasonably achievable. The Waste Handling Building Ventilation System interfaces with the Waste Handling Building System by being located within the WHB and by maintaining specific pressures, temperatures, and humidity within the building. The system also depends on the WHB for water supply. The system interfaces with the Site Radiological Monitoring System for continuous monitoring of the exhaust air; the Waste Handling Building Fire Protection System for detection of fire and smoke; the Waste Handling Building Electrical System for normal, emergency, and standby power; and the Monitored Geologic Repository Operations Monitoring and Control System for monitoring and control of the system.« less

HOW THE LEED VENTILATION CREDIT IMPACTS ENERGY CONSUMPTION OF GSHP SYSTEMS A CASE STUDY FOR PRIMARY SCHOOLS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Xiaobing

2011-01-01

This paper presents a study on the impacts of increased outdoor air (OA) ventilation on the performance of ground-source heat pump (GSHP) systems that heat and cool typical primary schools. Four locations Phoenix, Miami, Seattle, and Chicago are selected in this study to represent different climate zones in the United States. eQUEST, an integrated building and HVAC system energy analysis program, is used to simulate a typical primary school and the GSHP system at the four locations with minimum and 30% more than minimum OA ventilation. The simulation results show that, without an energy recovery ventilator, the 30% more OAmore » ventilation results in an 8.0 13.3% increase in total GSHP system energy consumption at the four locations. The peak heating and cooling loads increase by 20.2 30% and 14.9 18.4%, respectively, at the four locations. The load imbalance of the ground heat exchanger is increased in hot climates but reduced in mild and cold climates.« less

Potential risk for bacterial contamination in conventional reused ventilator systems and disposable closed ventilator-suction systems.

PubMed

Li, Ya-Chi; Lin, Hui-Ling; Liao, Fang-Chun; Wang, Sing-Siang; Chang, Hsiu-Chu; Hsu, Hung-Fu; Chen, Sue-Hsien; Wan, Gwo-Hwa

2018-01-01

Few studies have investigated the difference in bacterial contamination between conventional reused ventilator systems and disposable closed ventilator-suction systems. The aim of this study was to investigate the bacterial contamination rates of the reused and disposable ventilator systems, and the association between system disconnection and bacterial contamination of ventilator systems. The enrolled intubated and mechanically ventilated patients used a conventional reused ventilator system and a disposable closed ventilator-suction system, respectively, for a week; specimens were then collected from the ventilator circuit systems to evaluate human and environmental bacterial contamination. The sputum specimens from patients were also analyzed in this study. The detection rate of bacteria in the conventional reused ventilator system was substantially higher than that in the disposable ventilator system. The inspiratory and expiratory limbs of the disposable closed ventilator-suction system had higher bacterial concentrations than the conventional reused ventilator system. The bacterial concentration in the heated humidifier of the reused ventilator system was significantly higher than that in the disposable ventilator system. Positive associations existed among the bacterial concentrations at different locations in the reused and disposable ventilator systems, respectively. The predominant bacteria identified in the reused and disposable ventilator systems included Acinetobacter spp., Bacillus cereus, Elizabethkingia spp., Pseudomonas spp., and Stenotrophomonas (Xan) maltophilia. Both the reused and disposable ventilator systems had high bacterial contamination rates after one week of use. Disconnection of the ventilator systems should be avoided during system operation to decrease the risks of environmental pollution and human exposure, especially for the disposable ventilator system. ClinicalTrials.gov PRS / NCT03359148.

Energy saving effect of desiccant ventilation system using Wakkanai siliceous shale

NASA Astrophysics Data System (ADS)

Nabeshima, Yuki; Togawa, Jun-ya; Nagano, Katsunori; Kazuyo, Tsuzuki

2017-10-01

The nuclear power station accident resulting from the Great East Japan Earthquake disaster has resulted in a constrained electricity supply. However, in this Asian region there is high temperature and high humidity and consequently dehumidification process requires a huge amount of energy. This is the reason for the increasing energy consumption in the residential and commercial sectors. Accordingly, a high efficiency air-conditioning system is needed to be developed. The desiccant ventilation system is effective to reduce energy consumption for the dehumidification process. This system is capable of dehumidifying without dew condensing unlike a conventional air-conditioning system. Then we focused on Wakkanai Siliceous Shale (WSS) as a desiccant material to develop a new desiccant ventilation system. This is low priced, high performance, new type of thing. The aim of this study is to develop a desiccant ventilation unit using the WSS rotor which can be regenerated with low-temperature by numerical calculation. The results of performance prediction of the desiccant unit, indicate that it is possible to regenerate the WSS rotor at low-temperature of between 35 - 45 °C. In addition, we produced an actual measurement for the desiccant unit and air-conditioning unit. This air-conditioning system was capable to reduce roughly 40 % of input energy consumption.

VWPS: A Ventilator Weaning Prediction System with Artificial Intelligence

NASA Astrophysics Data System (ADS)

Chen, Austin H.; Chen, Guan-Ting

How to wean patients efficiently off mechanical ventilation continues to be a challenge for medical professionals. In this paper we have described a novel approach to the study of a ventilator weaning prediction system (VWPS). Firstly, we have developed and written three Artificial Neural Network (ANN) algorithms to predict a weaning successful rate based on the clinical data. Secondly, we have implemented two user-friendly weaning success rate prediction systems; the VWPS system and the BWAP system. Both systems could be used to help doctors objectively and effectively predict whether weaning is appropriate for patients based on the patients' clinical data. Our system utilizes the powerful processing abilities of MatLab. Thirdly, we have calculated the performance through measures such as sensitivity and accuracy for these three algorithms. The results show a very high sensitivity (around 80%) and accuracy (around 70%). To our knowledge, this is the first design approach of its kind to be used in the study of ventilator weaning success rate prediction.

Measure Guideline: Passive Vents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berger, David; Neri, Robin

2016-02-05

This document addresses the use of passive vents as a source of outdoor air in multifamily buildings. The challenges associated with implementing passive vents and the factors affecting performance are outlined. A comprehensive design methodology and quantified performance metrics are provided. Two hypothetical design examples are provided to illustrate the process. This document is intended to be useful to designers, decision-makers, and contractors implementing passive ventilation strategies. It is also intended to be a resource for those responsible for setting high-performance building program requirements, especially pertaining to ventilation and outdoor air. To ensure good indoor air quality, a dedicated sourcemore » of outdoor air is an integral part of high-performance buildings. Presently, there is a lack of guidance pertaining to the design and installation of passive vents, resulting in poor system performance. This report details the criteria necessary for designing, constructing, and testing passive vent systems to enable them to provide consistent and reliable levels of ventilation air from outdoors.« less

Potential risk for bacterial contamination in conventional reused ventilator systems and disposable closed ventilator-suction systems

PubMed Central

Li, Ya-Chi; Lin, Hui-Ling; Liao, Fang-Chun; Wang, Sing-Siang; Chang, Hsiu-Chu; Hsu, Hung-Fu; Chen, Sue-Hsien

2018-01-01

Background Few studies have investigated the difference in bacterial contamination between conventional reused ventilator systems and disposable closed ventilator-suction systems. The aim of this study was to investigate the bacterial contamination rates of the reused and disposable ventilator systems, and the association between system disconnection and bacterial contamination of ventilator systems. Methods The enrolled intubated and mechanically ventilated patients used a conventional reused ventilator system and a disposable closed ventilator-suction system, respectively, for a week; specimens were then collected from the ventilator circuit systems to evaluate human and environmental bacterial contamination. The sputum specimens from patients were also analyzed in this study. Results The detection rate of bacteria in the conventional reused ventilator system was substantially higher than that in the disposable ventilator system. The inspiratory and expiratory limbs of the disposable closed ventilator-suction system had higher bacterial concentrations than the conventional reused ventilator system. The bacterial concentration in the heated humidifier of the reused ventilator system was significantly higher than that in the disposable ventilator system. Positive associations existed among the bacterial concentrations at different locations in the reused and disposable ventilator systems, respectively. The predominant bacteria identified in the reused and disposable ventilator systems included Acinetobacter spp., Bacillus cereus, Elizabethkingia spp., Pseudomonas spp., and Stenotrophomonas (Xan) maltophilia. Conclusions Both the reused and disposable ventilator systems had high bacterial contamination rates after one week of use. Disconnection of the ventilator systems should be avoided during system operation to decrease the risks of environmental pollution and human exposure, especially for the disposable ventilator system. Trial registration ClinicalTrials.gov PRS / NCT03359148 PMID:29547638

Assessment of Natural Ventilation System for a Typical Residential House in Poland

NASA Astrophysics Data System (ADS)

Antczak-Jarząbska, Romana; Krzaczek, Marek

2016-09-01

The paper presents the research results of field measurements campaign of natural ventilation performance and effectiveness in a residential building. The building is located in the microclimate whose parameters differ significantly in relation to a representative weather station. The measurement system recorded climate parameters and the physical variables characterizing the air flow in the rooms within 14 days of the winter season. The measurement results showed that in spite of proper design and construction of the ventilation system, unfavorable microclimatic conditions that differed from the predicted ones caused significant reduction in the efficiency of the ventilation system. Also, during some time periods, external climate conditions caused an opposite air flow direction in the vent inlets and outlets, leading to a significant deterioration of air quality and thermal comfort measured by CO2 concentration and PMV index in a residential area.

Procedures and Standards for Residential Ventilation System Commissioning: An Annotated Bibliography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stratton, J. Chris; Wray, Craig P.

2013-04-01

Beginning with the 2008 version of Title 24, new homes in California must comply with ANSI/ASHRAE Standard 62.2-2007 requirements for residential ventilation. Where installed, the limited data available indicate that mechanical ventilation systems do not always perform optimally or even as many codes and forecasts predict. Commissioning such systems when they are installed or during subsequent building retrofits is a step towards eliminating deficiencies and optimizing the tradeoff between energy use and acceptable IAQ. Work funded by the California Energy Commission about a decade ago at Berkeley Lab documented procedures for residential commissioning, but did not focus on ventilation systems.more » Since then, standards and approaches for commissioning ventilation systems have been an active area of work in Europe. This report describes our efforts to collect new literature on commissioning procedures and to identify information that can be used to support the future development of residential-ventilation-specific procedures and standards. We recommend that a standardized commissioning process and a commissioning guide for practitioners be developed, along with a combined energy and IAQ benefit assessment standard and tool, and a diagnostic guide for estimating continuous pollutant emission rates of concern in residences (including a database that lists emission test data for commercially-available labeled products).« less

Ventilation and infiltration in high-rise apartment buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diamond, R.C.; Feustel, H.E.; Dickerhoff, D.J.

1996-03-01

Air flow, air leakage measurements and numerical simulations were made on a 13-story apartment building to characterize the ventilation rates for the individual apartments. Parametric simulations were performed for specific conditions, e.g., height, orientation, outside temperature and wind speed. Our analysis of the air flow simulations suggest that the ventilation to the individual units varies considerably. With the mechanical ventilation system disabled and no wind, units at the lower level of the building have adequate ventilation only on days with high temperature differences, while units on higher floors have no ventilation at all. Units facing the windward side will bemore » over-ventilated when the building experiences wind directions between west and north. At the same time, leeward apartments did not experience any fresh air-because, in these cases, air flows enter the apartments from the corridor and exit through the exhaust shafts and the cracks in the facade. Even with the mechanical ventilation system operating, we found wide variation in the air flows to the individual apartments. In addition to the specific case presented here, these findings have more general implications for energy retrofits and health and comfort of occupants in high-rise apartment buildings.« less

Fourier-based linear systems description of free-breathing pulmonary magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Capaldi, D. P. I.; Svenningsen, S.; Cunningham, I. A.; Parraga, G.

2015-03-01

Fourier-decomposition of free-breathing pulmonary magnetic resonance imaging (FDMRI) was recently piloted as a way to provide rapid quantitative pulmonary maps of ventilation and perfusion without the use of exogenous contrast agents. This method exploits fast pulmonary MRI acquisition of free-breathing proton (1H) pulmonary images and non-rigid registration to compensate for changes in position and shape of the thorax associated with breathing. In this way, ventilation imaging using conventional MRI systems can be undertaken but there has been no systematic evaluation of fundamental image quality measurements based on linear systems theory. We investigated the performance of free-breathing pulmonary ventilation imaging using a Fourier-based linear system description of each operation required to generate FDMRI ventilation maps. Twelve subjects with chronic obstructive pulmonary disease (COPD) or bronchiectasis underwent pulmonary function tests and MRI. Non-rigid registration was used to co-register the temporal series of pulmonary images. Pulmonary voxel intensities were aligned along a time axis and discrete Fourier transforms were performed on the periodic signal intensity pattern to generate frequency spectra. We determined the signal-to-noise ratio (SNR) of the FDMRI ventilation maps using a conventional approach (SNRC) and using the Fourier-based description (SNRF). Mean SNR was 4.7 ± 1.3 for subjects with bronchiectasis and 3.4 ± 1.8, for COPD subjects (p>.05). SNRF was significantly different than SNRC (p<.01). SNRF was approximately 50% of SNRC suggesting that the linear system model well-estimates the current approach.

Reproductive Performance of Mice in Disposable and Standard Individually Ventilated Cages

PubMed Central

Ferguson, Danielle R; Bailey, Michele M

2013-01-01

This study assessed the reproductive performance of mice housed in 2 types of individually ventilated caging systems. Breeding pairs from 48 female and 24 male mice of 3 established transgenic mouse breeding colonies were placed in either a standard or disposable ventilated caging system. For 3 breeding cycles, the number of pups born, pup survival rate to weaning, time interval between litters, and pup weights were monitored for each breeding pair. Disposable and standard cages were maintained in the same location during breeding. Environmental parameters included intracage temperature, humidity, and ammonia and carbon dioxide levels and room light intensity and sound. Overall, 776 offspring were produced. Breeding performance did not differ significantly between the 2 cage types. By 11 wk of age, the weights of pups from both cage types were equivalent. The intracage temperature was 1.1 °F warmer and light intensity at the site of the nest was 34 lx dimmer in disposable cages than in standard caging. The difference in lighting likely was due to nest location; the nests in the disposable cages were at the back of the cages and away from the anterior air supply, whereas in standard caging, nests were at the front of the cages, with the air supply at the rear. Under these husbandry conditions, mice housed in disposable caging systems have comparable breeding performance to those housed in standard individually ventilated cages. PMID:23849403

The respiratory system during resuscitation: a review of the history, risk of infection during assisted ventilation, respiratory mechanics, and ventilation strategies for patients with an unprotected airway.

PubMed

Wenzel, V; Idris, A H; Dörges, V; Nolan, J P; Parr, M J; Gabrielli, A; Stallinger, A; Lindner, K H; Baskett, P J

2001-05-01

The fear of acquiring infectious diseases has resulted in reluctance among healthcare professionals and the lay public to perform mouth-to-mouth ventilation. However, the benefit of basic life support for a patient in cardiopulmonary or respiratory arrest greatly outweighs the risk for secondary infection in the rescuer or the patient. The distribution of ventilation volume between lungs and stomach in the unprotected airway depends on patient variables such as lower oesophageal sphincter pressure, airway resistance and respiratory system compliance, and the technique applied while performing basic or advanced airway support, such as head position, inflation flow rate and time, which determine upper airway pressure. The combination of these variables determines gas distribution between the lungs and the oesophagus and subsequently, the stomach. During bag-valve-mask ventilation of patients in respiratory or cardiac arrest with oxygen supplementation (> or = 40% oxygen), a tidal volume of 6-7 ml kg(-1) ( approximately 500 ml) given over 1-2 s until the chest rises is recommended. For bag-valve-mask ventilation with room-air, a tidal volume of 10 ml kg(-1) (700-1000 ml) in an adult given over 2 s until the chest rises clearly is recommended. During mouth-to-mouth ventilation, a breath over 2 s sufficient to make the chest rise clearly (a tidal volume of approximately 10 ml kg(-1) approximately 700-1000 ml in an adult) is recommended.

Operating theatre ventilation systems and microbial air contamination in total joint replacement surgery: results of the GISIO-ISChIA study.

PubMed

Agodi, A; Auxilia, F; Barchitta, M; Cristina, M L; D'Alessandro, D; Mura, I; Nobile, M; Pasquarella, C

2015-07-01

Recent studies have shown a higher rate of surgical site infections in hip prosthesis implantation using unidirectional airflow ventilation compared with turbulent ventilation. However, these studies did not measure the air microbial quality of operating theatres (OTs), and assumed it to be compliant with the recommended standards for this ventilation technique. To evaluate airborne microbial contamination in OTs during hip and knee replacement surgery, and compare the findings with values recommended for joint replacement surgery. Air samplings were performed in 28 OTs supplied with unidirectional, turbulent and mixed airflow ventilation. Samples were collected using passive sampling to determine the index of microbial air contamination (IMA). Active sampling was also performed in some of the OTs. The average number of people in the OT and the number of door openings during the sampling period were recorded. In total, 1228 elective prosthesis procedures (60.1% hip and 39.9% knee) were included in this study. Of passive samplings performed during surgical activity in unidirectional airflow ventilation OTs (U-OTs) and mixed airflow OTs (M-OTs), 58.9% and 87.6% had IMA values >2, respectively. Of samplings performed during surgical activity in turbulent airflow OTs (T-OTs) and in turbulent airflow OTs with the surgical team wearing Steri-Shield Turbo Helmets (TH-OTs), 8.6% and 60% had IMA values ≤ 2, respectively. Positive correlation was found between IMA values and the number of people in the OT and the number of door openings (P < 0.001). In addition, correlation was found between active and passive sampling (P < 0.001). These findings challenge the belief that unidirectional systems always provide acceptable airborne bacterial counts. Copyright © 2015 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

The effect of helium on ventilator performance: study of five ventilators and a bedside Pitot tube spirometer.

PubMed

Oppenheim-Eden, A; Cohen, Y; Weissman, C; Pizov, R

2001-08-01

To assess in vitro the performance of five mechanical ventilators-Siemens 300 and 900C (Siemens-Elma; Solna, Sweden), Puritan Bennett 7200 (Nellcor Puritan Bennett; Pleasanton, CA), Evita 4 (Dragerwerk; Lubeck, Germany), and Bear 1000 (Bear Medical Systems; Riverside CA)-and a bedside sidestream spirometer (Datex CS3 Respiratory Module; Datex-Ohmeda; Helsinki, Finland) during ventilation with helium-oxygen mixtures. In vitro study. ICUs of two university-affiliated hospitals. Each ventilator was connected to 100% helium through compressed air inlets and then tested at three to six different tidal volume (VT) settings using various helium-oxygen concentrations (fraction of inspired oxygen [FIO(2)] of 0.2 to 1.0). FIO(2) and VT were measured with the Datex CS3 spirometer, and VT was validated with a water-displacement spirometer. The Puritan Bennett 7200 ventilator did not function with helium. With the other four ventilators, delivered FIO(2) was lower than the set FIO(2). For the Siemens 300 and 900C ventilators, this difference could be explained by the lack of 21% oxygen when helium was connected to the air supply port, while for the other two ventilators, a nonlinear relation was found. The VT of the Siemens 300 ventilator was independent of helium concentration, while for the other three ventilators, delivered VT was greater than the set VT and was dependent on helium concentration. During ventilation with 80% helium and 20% oxygen, VT increased to 125% of set VT for the Siemens 900C ventilator, and more than doubled for the Evita 4 and Bear 1000 ventilators. Under the same conditions, the Datex CS3 spirometer underestimated the delivered VT by about 33%. At present, no mechanical ventilator is calibrated for use with helium. This investigation offers correction factors for four ventilators for ventilation with helium.

Multifamily Individual Heating and Ventilation Systems, Lawrence, Massachusetts (Fact Sheet)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

The conversion of an older Massachusetts building into condominiums illustrates a safe, durable, and cost-effective solution for heating and ventilation systems that can potentially benefit millions of multifamily buildings. Merrimack Valley Habitat for Humanity (MVHfH) partnered with U.S. Department of Energy Building America team Building Science Corporation (BSC) to provide high performance affordable housing for 10 families in the retrofit of an existing mass masonry building (a former convent). The original ventilation design for the project was provided by a local engineer and consisted of a single large heat recovery ventilator (HRV) located in a mechanical room in the basementmore » with a centralized duct system providing supply air to the main living space and exhausting stale air from the single bathroom in each apartment. This design was deemed to be far too costly to install and operate for several reasons: the large central HRV was oversized and the specified flows to each apartment were much higher than the ASHRAE 62.2 rate; an extensive system of ductwork, smoke and fire dampers, and duct chases were specified; ductwork required a significant area of dropped ceilings; and the system lacked individual ventilation control in the apartments« less

46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-1 Power ventilation systems except machinery space ventilation systems. Each power ventilation system must... 46 Shipping 4 2010-10-01 2010-10-01 false Power ventilation systems except machinery space...

46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-1 Power ventilation systems except machinery space ventilation systems. Each power ventilation system must... 46 Shipping 4 2011-10-01 2011-10-01 false Power ventilation systems except machinery space...

46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-1 Power ventilation systems except machinery space ventilation systems. Each power ventilation system must... 46 Shipping 4 2014-10-01 2014-10-01 false Power ventilation systems except machinery space...

46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-1 Power ventilation systems except machinery space ventilation systems. Each power ventilation system must... 46 Shipping 4 2012-10-01 2012-10-01 false Power ventilation systems except machinery space...

46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-1 Power ventilation systems except machinery space ventilation systems. Each power ventilation system must... 46 Shipping 4 2013-10-01 2013-10-01 false Power ventilation systems except machinery space...

A novel fiber-optic measurement system for the evaluation of performances of neonatal pulmonary ventilators

NASA Astrophysics Data System (ADS)

Battista, L.; Scorza, A.; Botta, F.; Sciuto, S. A.

2016-02-01

Published standards for the performance evaluation of pulmonary ventilators are mainly directed to manufacturers rather than to end-users and often considered inadequate or not comprehensive. In order to contribute to overcome the problems above, a novel measurement system was proposed and tested with waveforms of mechanical ventilation by means of experimental trials carried out with infant ventilators typically used in neonatal intensive care units: the main quantities of mechanical ventilation in newborns are monitored, i.e. air flow rate, differential pressure and volume from infant ventilator are measured by means of two novel fiber-optic sensors (OFSs) developed and characterized by the authors, while temperature and relative humidity of air mass are obtained by two commercial transducers. The proposed fiber-optic sensors (flow sensor Q-OFS, pressure sensor P-OFS) showed measurement ranges of air flow and pressure typically encountered in neonatal mechanical ventilation, i.e. the air flow rate Q ranged from 3 l min-1 to 18 l min-1 (inspiratory) and from  -3 l min-1 to  -18 l min-1 (expiratory), the differential pressure ΔP ranged from  -15 cmH2O to 15 cmH2O. In each experimental trial carried out with different settings of the ventilator, outputs of the OFSs are compared with data from two reference sensors (reference flow sensor RF, reference pressure sensor RP) and results are found consistent: flow rate Q showed a maximum error between Q-OFS and RF up to 13 percent, with an output ratio Q RF/Q OFS of not more than 1.06  ±  0.09 (least square estimation, 95 percent confidence level, R 2 between 0.9822 and 0.9931). On the other hand the maximum error between P-OFS and RP on differential pressure ΔP was lower than 10 percent, with an output ratio ΔP RP/ΔP OFS between 0.977  ±  0.022 and 1.0  ±  0.8 (least square estimation, 95 percent confidence level, R 2 between 0.9864 and 0.9876). Despite the possible improvements, results were encouraging and suggested the proposed measurement system can be considered suitable for performances evaluation of neonatal ventilators and useful for both end-users and manufacturers.

Effects of elevated carbon dioxide concentrations on broiler chicken performance from 28 to 49 days

USDA-ARS?s Scientific Manuscript database

Improvements in modern broiler housing have substantially reduced air leakage, making proper operation of ventilation systems critical to maintaining a suitable environment. Fuel prices have increased in recent years, leading to reduced minimum ventilation in order to conserve fuel which increases ...

Case Study for the ARRA-funded Ground Source Heat Pump (GSHP) Demonstration at Wilders Grove Solid Waste Service Center in Raleigh, NC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Xiaobing; Malhotra, Mini; Xiong, Zeyu

High initial costs and lack of public awareness of ground-source heat pump (GSHP) technology are the two major barriers preventing rapid deployment of this energy-saving technology in the United States. Under the American Recovery and Reinvestment Act (ARRA), 26 GSHP projects have been competitively selected and carried out to demonstrate the benefits of GSHP systems and innovative technologies for cost reduction and/or performance improvement. This paper highlights the findings of a case study of one of the ARRA-funded GSHP demonstration projects, a distributed GSHP system for providing all the space conditioning, outdoor air ventilation, and 100% domestic hot water tomore » the Wilders Grove Solid Waste Service Center of City of Raleigh, North Carolina. This case study is based on the analysis of measured performance data, construction costs, and simulations of the energy consumption of conventional central heating, ventilation, and air-conditioning (HVAC) systems providing the same level of space conditioning and outdoor air ventilation as the demonstrated GSHP system. The evaluated performance metrics include the energy efficiency of the heat pump equipment and the overall GSHP system, pumping performance, energy savings, carbon emission reductions, and cost-effectiveness of the GSHP system compared with conventional HVAC systems. This case study also identified opportunities for reducing uncertainties in the performance evaluation and improving the operational efficiency of the demonstrated GSHP system.« less

Building America Case Study: Design Guidance for Passive Vents in New Construction Multifamily Buildings, New York, New York

DOE Office of Scientific and Technical Information (OSTI.GOV)

2016-02-01

This document addresses the use of passive vents as a source of outdoor air in multifamily buildings. The challenges associated with implementing passive vents and the factors affecting performance are outlined. A comprehensive design methodology and quantified performance metrics are provided. Two hypothetical design examples are provided to illustrate the process. This document is intended to be useful to designers, decision-makers, and contractors implementing passive ventilation strategies. It is also intended to be a resource for those responsible for setting high-performance building program requirements, especially pertaining to ventilation and outdoor air. To ensure good indoor air quality, a dedicated sourcemore » of outdoor air is an integral part of high-performance buildings. Presently, there is a lack of guidance pertaining to the design and installation of passive vents, resulting in poor system performance. This report details the criteria necessary for designing, constructing, and testing passive vent systems to enable them to provide consistent and reliable levels of ventilation air from outdoors.« less

Use of computational fluid dynamics in optimization of natural smoke ventilation from a historical shopping mall - Case study

NASA Astrophysics Data System (ADS)

Krajewski, Grzegorz; Wegrzyński, Wojciech

2018-01-01

In this paper, the Authors present results of a complex case study, in which a natural smoke ventilation system was introduced into a historical mall Koszyki Market Hall located in the centre of Warsaw. As historical authorities protected the building, the only solution possible was to use a natural system - known for deficient performance in façade applications. To maximise the performance of the smoke control system, a Computational Wind Engineering exercise was performed. The goal was to find the most difficult wind attack angles, and optimise the performance at these conditions. Once the wind influence was known, a transient analysis was performed that included the growth of the fire within the building, as well as a numerical evacuation study. The resulting system was immune to the wind effects, and provided safe evacuation to users of the building, even in difficult wind conditions.

Pipe crawler development for duct elbow removal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zollinger, W.T.; Treanor, R.C.

1992-01-01

This paper describes the development of equipment for removing an elbow in a 36 inch diameter ventilation line by cutting from the inside. Radiation levels, high air flow and physical constraints preclude any manual rework of the ventilation system. A remotely operated pipe crawler was developed. Testing has been performed in a full-scale mockup which models the ventilation duct configuration with the exception of radiation levels. The results gathered from the testing are discussed, and illustrate the strengths and weaknesses of the crawler and plasma arc torch system. To date, the equipment has successfully completed the tasks of maneuvering throughmore » the duct geometry, performing the two required cuts, and backing out of the duct mockup. The elbow successfully fell away from the main duct, showing that the line would be clear of obstructions.« less

Pipe crawler development for duct elbow removal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zollinger, W.T.; Treanor, R.C.

1992-11-01

This paper describes the development of equipment for removing an elbow in a 36 inch diameter ventilation line by cutting from the inside. Radiation levels, high air flow and physical constraints preclude any manual rework of the ventilation system. A remotely operated pipe crawler was developed. Testing has been performed in a full-scale mockup which models the ventilation duct configuration with the exception of radiation levels. The results gathered from the testing are discussed, and illustrate the strengths and weaknesses of the crawler and plasma arc torch system. To date, the equipment has successfully completed the tasks of maneuvering throughmore » the duct geometry, performing the two required cuts, and backing out of the duct mockup. The elbow successfully fell away from the main duct, showing that the line would be clear of obstructions.« less

Microclimate measuring and fluid‑dynamic simulation in an industrial broiler house: testing of an experimental ventilation system.

PubMed

Bianchi, Biagio; Giametta, Ferruccio; La Fianza, Giovanna; Gentile, Andrea; Catalano, Pasquale

2015-01-01

The environment in the broiler house is a combination of physical and biological factors generating a complex dynamic system of interactions between birds, husbandry system, light, temperature, and the aerial environment. Ventilation plays a key role in this scenario. It is pivotal to remove carbon dioxide and water vapor from the air of the hen house. Adequate ventilation rates provide the most effective method of controlling temperature within the hen house. They allow for controlling the relative humidity and can play a key role in alleviating the negative effects of high stocking density and of wet litter. In the present study the results of experimental tests performed in a breeding broiler farm are shown. In particular the efficiency of a semi transversal ventilation system was studied against the use of a pure transversal one. In order to verify the efficiency of the systems, fluid dynamic simulations were carried out using the software Comsol multiphysics. The results of this study show that a correct architectural and structural design of the building must be supported by a design of the ventilation system able to maintain the environmental parameters within the limits of the thermo‑neutral and welfare conditions and to achieve the highest levels of productivity.

[Statement of the Association of Pneumological Clinics and the German Respiratory Society on the coding of invasive and non-invasive ventilation in intensity care].

PubMed

2013-07-01

Mechanical ventilation in patients with respiratory failure represents one of the most important aspects of intensity care. It can be performed invasively and non-invasively depending on the clinical situation and the underlying disease. The expenditure and consumption of resources is the basis of the compensation for each patient case in the German diagnosis related group system. For ventilated patients it is calculated based on the hours of ventilation, according to the standard coding guideline. In this statement, the German Respiratory Society and the Association of Pneumological Clinics aim to clarify some aspects of the coding of invasive and non-invasive ventilation. © Georg Thieme Verlag KG Stuttgart · New York.

International Space Station Crew Quarters Ventilation and Acoustic Design Implementation

NASA Technical Reports Server (NTRS)

Broyan, James L., Jr.; Cady, Scott M; Welsh, David A.

2010-01-01

The International Space Station (ISS) United States Operational Segment has four permanent rack sized ISS Crew Quarters (CQs) providing a private crew member space. The CQs use Node 2 cabin air for ventilation/thermal cooling, as opposed to conditioned ducted air-from the ISS Common Cabin Air Assembly (CCAA) or the ISS fluid cooling loop. Consequently, CQ can only increase the air flow rate to reduce the temperature delta between the cabin and the CQ interior. However, increasing airflow causes increased acoustic noise so efficient airflow distribution is an important design parameter. The CQ utilized a two fan push-pull configuration to ensure fresh air at the crew member's head position and reduce acoustic exposure. The CQ ventilation ducts are conduits to the louder Node 2 cabin aisle way which required significant acoustic mitigation controls. The CQ interior needs to be below noise criteria curve 40 (NC-40). The design implementation of the CQ ventilation system and acoustic mitigation are very inter-related and require consideration of crew comfort balanced with use of interior habitable volume, accommodation of fan failures, and possible crew uses that impact ventilation and acoustic performance. Each CQ required 13% of its total volume and approximately 6% of its total mass to reduce acoustic noise. This paper illustrates the types of model analysis, assumptions, vehicle interactions, and trade-offs required for CQ ventilation and acoustics. Additionally, on-orbit ventilation system performance and initial crew feedback is presented. This approach is applicable to any private enclosed space that the crew will occupy.

Bacterial dispersion in relation to operating room clothing.

PubMed Central

Whyte, W.; Vesley, D.; Hodgson, R.

1976-01-01

The effect of operating clothing on the dispersal of bacterial particles from the wearers was studied in a dispersal chamber. A comparison was made of six gowns as well as four types of trousers. The gowns were of three basic types, namely a conventional cotton type, disposable types made of non-woven fabric and those of the total-body exhaust system (Charnley type). The dispersal chamber could simulate conditions as expected both in down-flow unidirectional ultra-clean systems and in a conventional turbulent plenum-ventilated system. It was found that the disposable gowns would reduce the dispersal rate by about 30% in the simulated conventionally ventilated system and about 65% in the laminar flow system. The total-body exhaust system (Charnley) would reduce the count by 10-fold in the conventional ventilated system and by 66-fold in the laminar-flow system. The poor performance of the gowns in conventionally ventilated systems was caused by the dispersal of bacterial particles from underneath the gown (about 80%). This was not reduced by the disposable gown and only partially by the Charnley type. This small drop would be further decreased in a conventionally ventilated operating-room as only scrubbed staff would wear the gown. In order to overcome this poor performance in conventionally ventilated operating-rooms impervious trousers would be required. Four types were studied and it was demonstrated that those made either from Ventile or non-woven fabric would reduce the bacterial dispersion fourfold. As these tests had been carried out in an artificial environment checks were carried out in the unidirectional-flow operating-room during total-hip arthroplasty. This was done by comparing conventional cotton gowns with non-woven gowns and total-body exhaust gowns. The results showed good correlation between the operating room and the chamber with the non-woven fabric gown but the total-body exhaust system did not perform as well in the operating room (12-fold compared to 66-fold) the difference being possibly due to the contribution from the patient. However, as this comparison was that which would be most open to influence from other variables confidence could be placed on the chamber test results. Values were also obtained for the total number of bacterial particles dispersed by persons during a standard exercise wearing different clothing. This count was dependent on the clothing worn but a median count of between 1000 and 1500 bacterial particles/min. would be expected when conventional clothing was worn, with a range of between 300 and 19,000. This count could be reduced to about 100/min. if a total-body exhaust suit was worn (range 30-400). PMID:778258

Building America Case Study: Evaluation of Ventilation Strategies in New Construction Multifamily Buildings, New York, New York (Fact Sheet)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2014-09-01

In multifamily buildings, particularly in the Northeast, exhaust ventilation strategies are the norm as a means of meeting both local exhaust and whole-unit mechanical ventilation rates. The issue of where the 'fresh' air is coming from is gaining significance as air-tightness standards for enclosures become more stringent, and the 'normal leakage paths through the building envelope' disappear. CARB researchers have found that the majority of high performance, new construction, multifamily housing in the Northeast use one of four general strategies for ventilation: continuous exhaust only with no designated supply or make-up air source, continuous exhaust with ducted make-up air tomore » apartments, continuous exhaust with supply through a make-up air device integral to the unit HVAC, and continuous exhaust with supply through a passive inlet device, such as a trickle vent. Insufficient information is available to designers on how these various systems are best applied. Product performance data are based on laboratory tests, and the assumption is that products will perform similarly in the field. Proper application involves matching expected performance at expected building pressures, but there is no guarantee that those conditions will exist consistently in the finished building. This research effort, which included several weeks of building pressure monitoring, sought to provide field validation of system performance. The performance of four substantially different strategies for providing make-up air to apartments was evaluated.« less

Exploration Mission Particulate Matter Filtration Technology Performance Testing in a Simulated Spacecraft Cabin Ventilation System

NASA Technical Reports Server (NTRS)

Agui, Juan H.; Vijayakumar, R.; Perry, Jay L.; Frederick, Kenneth R.; Mccormick, Robert M.

2017-01-01

Human deep space exploration missions will require advances in long-life, low maintenance airborne particulate matter filtration technology. As one of the National Aeronautics and Space Administrations (NASA) developments in this area, a prototype of a new regenerable, multi-stage particulate matter filtration technology was tested in an International Space Station (ISS) module simulation facility. As previously reported, the key features of the filter system include inertial and media filtration with regeneration and in-place media replacement techniques. The testing facility can simulate aspects of the cabin environment aboard the ISS and contains flight-like cabin ventilation system components. The filtration technology test article was installed at the inlet of the central ventilation system duct and instrumented to provide performance data under nominal flow conditions. In-place regeneration operations were also evaluated. The real-time data included pressure drop across the filter stages, process air flow rate, ambient pressure, humidity and temperature. In addition, two video cameras positioned at the filtration technology test articles inlet and outlet were used to capture the mechanical performance of the filter media indexing operation under varying air flow rates. Recent test results are presented and future design recommendations are discussed.

Evaluation of Passive Vents in New Construction Multifamily Buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maxwell, Sean; Berger, David; Zuluaga, Marc

Exhaust ventilation and corresponding outdoor air strategies are being implemented in high-performance new construction multifamily buildings to meet program or code requirements for improved indoor air quality, but a lack of clear design guidance is resulting in poor performance of these systems despite the best intentions of the programs or standards. CARB's 2014 'Evaluation of Ventilation Strategies in New Construction Multifamily Buildings' consistently demonstrated that commonly used outdoor air strategies are not performing as expected. Of the four strategies evaluated in 2014, the exhaust ventilation system that relied on outdoor air from a pressurized corridor was ruled out as amore » potential best practice due to its conflict with meeting requirements within most fire codes. Outdoor air that is ducted directly to the apartments was a strategy determined to have the highest likelihood of success, but with higher first costs and operating costs. Outdoor air through space conditioning systems was also determined to have good performance potential, with proper design and execution. The fourth strategy, passive systems, was identified as the least expensive option for providing outdoor air directly to apartments, with respect to both first costs and operating costs. However, little is known about how they actually perform in real-world conditions or how to implement them effectively. Based on the lack of data available on the performance of these low-cost systems and their frequent use in the high-performance building programs that require a provision for outdoor air, this research project sought to further evaluate the performance of passive vents.« less

Building America Case Study: Evaluation of Passive Vents in New-Construction Multifamily Buildings, New York, New York

DOE Office of Scientific and Technical Information (OSTI.GOV)

Exhaust ventilation and corresponding outdoor air strategies are being implemented in high-performance new construction multifamily buildings to meet program or code requirements for improved indoor air quality, but a lack of clear design guidance is resulting in poor performance of these systems despite the best intentions of the programs or standards. CARB's 2014 'Evaluation of Ventilation Strategies in New Construction Multifamily Buildings' consistently demonstrated that commonly used outdoor air strategies are not performing as expected. Of the four strategies evaluated in 2014, the exhaust ventilation system that relied on outdoor air from a pressurized corridor was ruled out as amore » potential best practice due to its conflict with meeting requirements within most fire codes. Outdoor air that is ducted directly to the apartments was a strategy determined to have the highest likelihood of success, but with higher first costs and operating costs. Outdoor air through space conditioning systems was also determined to have good performance potential, with proper design and execution. The fourth strategy, passive systems, was identified as the least expensive option for providing outdoor air directly to apartments, with respect to both first costs and operating costs. However, little is known about how they actually perform in real-world conditions or how to implement them effectively. Based on the lack of data available on the performance of these low-cost systems and their frequent use in the high-performance building programs that require a provision for outdoor air, this research project sought to further evaluate the performance of passive vents.« less

A new system for understanding modes of mechanical ventilation.

PubMed

Chatburn, R L; Primiano, F P

2001-06-01

Numerous ventilation modes and ventilation options have become available as new mechanical ventilators have reached the market. Ventilator manufacturers have no standardized terminology for ventilator modes and ventilation options, and ventilator operator's manuals do not help the clinician compare the modes of ventilators from different manufacturers. This article proposes a standardized system for classifying ventilation modes, based on general engineering principles and a small set of explicit definitions. Though there may be resistance by ventilator manufacturers to a standardized system of ventilation terminology, clinicians and health care equipment purchasers should adopt such a system in the interest of clear communication--the lack of which prevents clinicians from fully understanding the therapies they administer and could compromise the quality of patient care.

Fire tests to evaluate the potential fire threat and its effects on HEPA filter integrity in cell ventilation at the Oak Ridge National Laboratory, Building 7920

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hasegawa, H.K.; Staggs, K.J.; Doughty, S.M.

1992-12-01

As a result of a DOE (Tiger Team) Technical Safety Appraisal (November 1990) of the Radiochemical Engineering Development Center (REDC), ORNL Building 7920, a number of fire protection concerns were identified. The primary concern was the perceived loss of ventilation system containment due to the thermal destruction and/or breaching of the prefilters and/or high-efficiency particulate air filters (HEPA `s) and the resultant radioactive release to the external environment. The following report describes the results of an extensive fire test program performed by the Fire Research Discipline (FRD) of the Special Projects Division of Lawrence Livermore National Lab (LLNL) and fundedmore » by ORNL to address these concerns. Full scale mock-ups of a REDC hot cell tank pit, adjacent cubicle pit, and associated ventilation system were constructed at LLNL and 13 fire experiments were conducted to specifically answer the questions raised by the Tiger Team. Our primary test plan was to characterize the burning of a catastrophic solvent spill (kerosene) of 40 liters and its effect on the containment ventilation system prefilters and HEPA filters. In conjunction with ORNL and Lockwood Greene we developed a test matrix that assessed the fire performance of the prefilters and HEPA filters; evaluated the fire response of the fiber reinforced plastic (FRP) epoxy ventilation duct work; the response and effectiveness of the fire protection system, the effect of fire in a cubicle on the vessel off-gas (VOG) elbow, and other fire safety questions.« less

Tracheostomy and mechanical ventilation weaning in children affected by respiratory virus according to a weaning protocol in a pediatric intensive care unit in Argentina: an observational restrospective trial

PubMed Central

2011-01-01

We describe difficult weaning after prolonged mechanical ventilation in three tracheostomized children affected by respiratory virus infection. Although the spontaneous breathing trials were successful, the patients failed all extubations. Therefore a tracheostomy was performed and the weaning plan was begun. The strategy for weaning was the decrease of ventilation support combining pressure control ventilation (PCV) with increasing periods of continuous positive airway pressure + pressure support ventilation (CPAP + PSV) and then CPAP + PSV with increasing intervals of T-piece. They presented acute respiratory distress syndrome on admission with high requirements of mechanical ventilation (MV). Intervening factors in the capabilities and loads of the respiratory system were considered and optimized. The average MV time was 69 days and weaning time 31 days. We report satisfactory results within the context of a directed weaning protocol. PMID:21244710

Indoor air quality in 24 California residences designed as high-performance homes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Less, Brennan; Mullen, Nasim; Singer, Brett

2015-01-01

Today’s high performance green homes are reaching previously unheard of levels of airtightness and are using new materials, technologies and strategies, whose impacts on Indoor Air Quality (IAQ) cannot be fully anticipated from prior studies. This research study used pollutant measurements, home inspections, diagnostic testing and occupant surveys to assess IAQ in 24 new or deeply retrofitted homes designed to be high performance green buildings in California. Although the mechanically vented homes were six times as airtight as non-mechanically ventilated homes (medians of 1.1 and 6.1 ACH 50, n=11 and n=8, respectively), their use of mechanical ventilation systems and possiblymore » window operation meant their median air exchange rates were almost the same (0.30 versus 0.32 hr -1, n=8 and n=8, respectively). Pollutant levels were also similar in vented and unvented homes. In addition, these similarities were achieved despite numerous observed faults in complex mechanical ventilation systems. More rigorous commissioning is still recommended. Cooking exhaust systems were used inconsistently and several suffered from design flaws. Failure to follow best practices led to IAQ problems in some cases. Ambient nitrogen dioxide standards were exceeded or nearly so in four homes that either used gas ranges with standing pilots, or in Passive House-style homes that used gas cooking burners without venting range hoods. Homes without active particle filtration had particle count concentrations approximately double those in homes with enhanced filtration. The majority of homes reported using low-emitting materials; consistent with this, formaldehyde levels were approximately half those in conventional, new CA homes built before 2008. Emissions of ultrafine particles (with diameters <100 nm) were dramatically lower on induction electric cooktops, compared with either gas or resistance electric models. These results indicate that high performance homes can achieve acceptable and even exceptional IAQ by providing adequate general mechanical ventilation, using low-emitting materials, providing mechanical particle filtration, incorporating well-designed exhaust ventilation for kitchens and bathrooms, and educating occupants to use the kitchen and bath ventilation.« less

46 CFR 154.1200 - Mechanical ventilation system: General.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Mechanical ventilation system: General. 154.1200 Section... Equipment Cargo Area: Mechanical Ventilation System § 154.1200 Mechanical ventilation system: General. (a... cargo handling equipment must have a fixed, exhaust-type mechanical ventilation system. (b) The...

Interactive simulation system for artificial ventilation on the internet: virtual ventilator.

PubMed

Takeuchi, Akihiro; Abe, Tadashi; Hirose, Minoru; Kamioka, Koichi; Hamada, Atsushi; Ikeda, Noriaki

2004-12-01

To develop an interactive simulation system "virtual ventilator" that demonstrates the dynamics of pressure and flow in the respiratory system under the combination of spontaneous breathing, ventilation modes, and ventilator options. The simulation system was designed to be used by unexperienced health care professionals as a self-training tool. The system consists of a simulation controller and three modules: respiratory, spontaneous breath, and ventilator. The respiratory module models the respiratory system by three resistances representing the main airway, the right and left lungs, and two compliances also representing the right and left lungs. The spontaneous breath module generates inspiratory negative pressure produced by a patient. The ventilator module generates driving force of pressure or flow according to the combination of the ventilation mode and options. These forces are given to the respiratory module through the simulation controller. The simulation system was developed using HTML, VBScript (3000 lines, 100 kB) and ActiveX control (120 kB), and runs on Internet Explorer (5.5 or higher). The spontaneous breath is defined by a frequency, amplitude and inspiratory patterns in the spontaneous breath module. The user can construct a ventilation mode by setting a control variable, phase variables (trigger, limit, and cycle), and options. Available ventilation modes are: controlled mechanical ventilation (CMV), continuous positive airway pressure, synchronized intermittent mandatory ventilation (SIMV), pressure support ventilation (PSV), SIMV + PSV, pressure-controlled ventilation (PCV), pressure-regulated volume control (PRVC), proportional assisted ventilation, mandatory minute ventilation (MMV), bilevel positive airway pressure (BiPAP). The simulation system demonstrates in a graph and animation the airway pressure, flow, and volume of the respiratory system during mechanical ventilation both with and without spontaneous breathing. We developed a web application that demonstrated the respiratory mechanics and the basic theory of ventilation mode.

Comparison of exogenous surfactant therapy, mechanical ventilation with high end-expiratory pressure and partial liquid ventilation in a model of acute lung injury.

PubMed

Hartog, A; Vazquez de Anda, G F; Gommers, D; Kaisers, U; Verbrugge, S J; Schnabel, R; Lachmann, B

1999-01-01

We have compared three treatment strategies, that aim to prevent repetitive alveolar collapse, for their effect on gas exchange, lung mechanics, lung injury, protein transfer into the alveoli and surfactant system, in a model of acute lung injury. In adult rats, the lungs were ventilated mechanically with 100% oxygen and a PEEP of 6 cm H2O, and acute lung injury was induced by repeated lung lavage to obtain a PaO2 value < 13 kPa. Animals were then allocated randomly (n = 12 in each group) to receive exogenous surfactant therapy, ventilation with high PEEP (18 cm H2O), partial liquid ventilation or ventilation with low PEEP (8 cm H2O) (ventilated controls). Blood-gas values were measured hourly. At the end of the 4-h study, in six animals per group, pressure-volume curves were constructed and bronchoalveolar lavage (BAL) was performed, whereas in the remaining animals lung injury was assessed. In the ventilated control group, arterial oxygenation did not improve and protein concentration of BAL and conversion of active to non-active surfactant components increased significantly. In the three treatment groups, PaO2 increased rapidly to > 50 kPa and remained stable over the next 4 h. The protein concentration of BAL fluid increased significantly only in the partial liquid ventilation group. Conversion of active to non-active surfactant components increased significantly in the partial liquid ventilation group and in the group ventilated with high PEEP. In the surfactant group and partial liquid ventilation groups, less lung injury was found compared with the ventilated control group and the group ventilated with high PEEP. We conclude that although all three strategies improved PaO2 to > 50 kPa, the impact on protein transfer into the alveoli, surfactant system and lung injury differed markedly.

46 CFR 154.1205 - Mechanical ventilation system: Standards.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Mechanical ventilation system: Standards. 154.1205... Equipment Cargo Area: Mechanical Ventilation System § 154.1205 Mechanical ventilation system: Standards. (a) Each exhaust type mechanical ventilation system required under § 154.1200 (a) must have ducts for...

Bench-test comparison of 26 emergency and transport ventilators.

PubMed

L'Her, Erwan; Roy, Annie; Marjanovic, Nicolas

2014-10-15

Numerous emergency and transport ventilators are commercialized and new generations arise constantly. The aim of this study was to evaluate a large panel of ventilators to allow clinicians to choose a device, taking into account their specificities of use. This experimental bench-test took into account general characteristics and technical performances. Performances were assessed under different levels of FIO2 (100%, 50% or Air-Mix), respiratory mechanics (compliance 30,70,120 mL/cmH2O; resistance 5,10,20 cmH2O/mL/s), and levels of leaks (3.5 to 12.5 L/min), using a test lung. In total 26 emergency and transport ventilators were analyzed and classified into four categories (ICU-like, n = 5; Sophisticated, n = 10; Simple, n = 9; Mass-casualty and military, n = 2). Oxygen consumption (7.1 to 15.8 L/min at FIO2 100%) and the Air-Mix mode (FIO2 45 to 86%) differed from one device to the other. Triggering performance was heterogeneous, but several sophisticated ventilators depicted triggering capabilities as efficient as ICU-like ventilators. Pressurization was not adequate for all devices. At baseline, all the ventilators were able to synchronize, but with variations among respiratory conditions. Leak compensation in most ICU-like and 4/10 sophisticated devices was able to correct at least partially for system leaks, but with variations among ventilators. Major differences were observed between devices and categories, either in terms of general characteristics or technical reliability, across the spectrum of operation. Huge variability of tidal volume delivery with some devices in response to modifications in respiratory mechanics and FIO2 should make clinicians question their use in the clinical setting.

The correlation of Acanthamoeba from the ventilation system with other environmental parameters in commercial buildings as possible indicator for indoor air quality.

PubMed

Ooi, Soo Shen; Mak, Joon Wah; Chen, Donald K F; Ambu, Stephen

2017-02-07

The free-living protozoan Acanthamoeba is an opportunistic pathogen that is ubiquitous in our environment. However, its role in affecting indoor air quality and ill-health of indoor occupants is relatively unknown. The present study investigated the presence of Acanthamoeba from the ventilation system and its correlation with other indoor air quality parameters, used in the industry code of practice and its potential as an indicator for indoor air quality. Indoor air quality assessments were carried out in nine commercial buildings with approval from the building management, and the parameters assessed were as recommended by the Department of Occupational Safety and Health. The presence of Acanthamoeba was determined through dust swabs from the ventilation system and indoor furniture. Logistic regression was performed to study the correlation between assessed parameters and occupants' complaints. A total of 107 sampling points were assessed and 40.2% of the supplying air diffuser and blowing fan and 15% of the furniture were positive for cysts. There was a significant correlation between Acanthamoeba detected from the ventilation system with ambient total fungus count (r=0.327; p=0.01) and respirable particulates (r=0.276; p=0.01). Occupants' sick building syndrome experience also correlated with the presence of Acanthamoeba in the ventilation system (r=0.361; p=0.01) and those detected on the furniture (r=0.290; p=0.01). Logistic regression showed that there was a five-fold probability of sick building syndrome among occupants when Acanthamoeba was detected in the ventilation system.

The correlation of Acanthamoeba from the ventilation system with other environmental parameters in commercial buildings as possible indicator for indoor air quality

PubMed Central

OOI, Soo Shen; MAK, Joon Wah; CHEN, Donald K.F.; AMBU, Stephen

2016-01-01

The free-living protozoan Acanthamoeba is an opportunistic pathogen that is ubiquitous in our environment. However, its role in affecting indoor air quality and ill-health of indoor occupants is relatively unknown. The present study investigated the presence of Acanthamoeba from the ventilation system and its correlation with other indoor air quality parameters, used in the industry code of practice and its potential as an indicator for indoor air quality. Indoor air quality assessments were carried out in nine commercial buildings with approval from the building management, and the parameters assessed were as recommended by the Department of Occupational Safety and Health. The presence of Acanthamoeba was determined through dust swabs from the ventilation system and indoor furniture. Logistic regression was performed to study the correlation between assessed parameters and occupants’ complaints. A total of 107 sampling points were assessed and 40.2% of the supplying air diffuser and blowing fan and 15% of the furniture were positive for cysts. There was a significant correlation between Acanthamoeba detected from the ventilation system with ambient total fungus count (r=0.327; p=0.01) and respirable particulates (r=0.276; p=0.01). Occupants’ sick building syndrome experience also correlated with the presence of Acanthamoeba in the ventilation system (r=0.361; p=0.01) and those detected on the furniture (r=0.290; p=0.01). Logistic regression showed that there was a five-fold probability of sick building syndrome among occupants when Acanthamoeba was detected in the ventilation system. PMID:27476379

NanoClusters Enhance Drug Delivery in Mechanical Ventilation

NASA Astrophysics Data System (ADS)

Pornputtapitak, Warangkana

The overall goal of this thesis was to develop a dry powder delivery system for patients on mechanical ventilation. The studies were divided into two parts: the formulation development and the device design. The pulmonary system is an attractive route for drug delivery since the lungs have a large accessible surface area for treatment or drug absorption. For ventilated patients, inhaled drugs have to successfully navigate ventilator tubing and an endotracheal tube. Agglomerates of drug nanoparticles (also known as 'NanoClusters') are fine dry powder aerosols that were hypothesized to enable drug delivery through ventilator circuits. This Thesis systematically investigated formulations of NanoClusters and their aerosol performance in a conventional inhaler and a device designed for use during mechanical ventilation. These engineered powders of budesonide (NC-Bud) were delivered via a MonodoseRTM inhaler or a novel device through commercial endotracheal tubes, and analyzed by cascade impaction. NC-Bud had a higher efficiency of aerosol delivery compared to micronized stock budesonide. The delivery efficiency was independent of ventilator parameters such as inspiration patterns, inspiration volumes, and inspiration flow rates. A novel device designed to fit directly to the ventilator and endotracheal tubing connections and the MonodoseRTM inhaler showed the same efficiency of drug delivery. The new device combined with NanoCluster formulation technology, therefore, allowed convenient and efficient drug delivery through endotracheal tubes. Furthermore, itraconazole (ITZ), a triazole antifungal agent, was formulated as a NanoCluster powder via milling (top-down process) or precipitation (bottom-up process) without using any excipients. ITZ NanoClusters prepared by wet milling showed better aerosol performance compared to micronized stock ITZ and ITZ NanoClusters prepared by precipitation. ITZ NanoClusters prepared by precipitation methods also showed an amorphous state while milled ITZ NanoClusters maintained the crystalline character. Overall, NanoClusters prepared by various processes represent a potential engineered drug particle approach for inhalation therapy since they provide effective aerosol properties and stability due to the crystalline state of the drug powders. Future work will continue to explore formulation and delivery performance in vitro and in vivo..

Low-Flow Liquid Desiccant Air Conditioning: General Guidance and Site Considerations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kozubal, E.; Herrmann, L.; Deru, M.

2014-09-01

Dehumidification or latent cooling in buildings is an area of growing interest that has been identified as needing more research and improved technologies for higher performance. Heating, ventilating, and air-conditioning (HVAC) systems typically expend excessive energy by using overcool-and-reheat strategies to dehumidify buildings. These systems first overcool ventilation air to remove moisture and then reheat the air to meet comfort requirements. Another common strategy incorporates solid desiccant rotors that remove moisture from the air more efficiently; however, these systems increase fan energy consumption because of the high airside pressure drop of solid desiccant rotors and can add heat of absorptionmore » to the ventilation air. Alternatively, liquid desiccant air-conditioning (LDAC) technology provides an innovative dehumidification solution that: (1) eliminates the need for overcooling and reheating from traditional cooling systems; and (2) avoids the increased fan energy and air heating from solid desiccant rotor systems.« less

33 CFR 183.620 - Natural ventilation system.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Natural ventilation system. 183... (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Ventilation § 183.620 Natural ventilation system. (a) Except for compartments open to the atmosphere, a natural ventilation system that meets the...

33 CFR 183.620 - Natural ventilation system.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Natural ventilation system. 183... (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Ventilation § 183.620 Natural ventilation system. (a) Except for compartments open to the atmosphere, a natural ventilation system that meets the...

Javanese House’s Roof (Joglo) with the Opening as a Cooling Energy Provider

NASA Astrophysics Data System (ADS)

Pranoto S, M.

2018-01-01

Natural ventilation and air movement could be considered under the heading structural controls as it does not rely on any form of energy supply or mechanical installation but due to its importance for human comfort, it deserves a separate section. Air infiltration can destroy the performance of ventilation systems. Good ventilation design combined with optimum air tightness is needed to ensure energy efficient ventilation. Ultimately, ventilation needs depend on occupancy pattern and building use. A full cost and energy analysis is therefore needed to select an optimum ventilation strategy.The contains of paper is about the element of Javanese house (the roof) as the element of natural ventilation and a cooling energy provider. In this research, The Computational Fluid Dynamics Program, is used to draw and analysis. That tool can be track the pattern and the direction of movement of air also the air velocity in the object of ventilation of the roof Javanese house based. Finally, the ventilation of the roof of this Javanese house can add the velocity of air at indoor, average 0.4 m/s and give the effect of cooling, average 0.7°C.

Night ventilation control strategies in office buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Zhaojun; Yi, Lingli; Gao, Fusheng

2009-10-15

In moderate climates night ventilation is an effective and energy-efficient approach to improve the indoor thermal environment for office buildings during the summer months, especially for heavyweight construction. However, is night ventilation a suitable strategy for office buildings with lightweight construction located in cold climates? In order to answer this question, the whole energy-consumption analysis software EnergyPlus was used to simulate the indoor thermal environment and energy consumption in typical office buildings with night mechanical ventilation in three cities in northern China. The summer outdoor climate data was analyzed, and three typical design days were chosen. The most important factorsmore » influencing night ventilation performance such as ventilation rates, ventilation duration, building mass and climatic conditions were evaluated. When night ventilation operation time is closer to active cooling time, the efficiency of night ventilation is higher. With night ventilation rate of 10 ach, the mean radiant temperature of the indoor surface decreased by up to 3.9 C. The longer the duration of operation, the more efficient the night ventilation strategy becomes. The control strategies for three locations are given in the paper. Based on the optimized strategies, the operation consumption and fees are calculated. The results show that more energy is saved in office buildings cooled by a night ventilation system in northern China than ones that do not employ this strategy. (author)« less

Ventilation.

PubMed

Turner, W A; Bearg, D W; Brennan, T

1995-01-01

This chapter begins with an overview of the history of ventilation guidelines, which has led to the guidelines that are in effect today. Of particular interest is the most recent return in the past 5 years to ventilation rates that more closely reflect a mean or average of the range of guidelines that have existed over the past century. OSHA's and the EPA's recognition of the need to operate ventilation systems in buildings in an accountable manner is also of note. Of even more interest is the resurgence of the concept of minimum mixing and once-through ventilation air that has been pursued in parts of Northern Europe for the past 10 years, and in a school that is being designed with this concept in New Hampshire. In addition, the design concept of equipping office buildings with low pressure drop high efficiency particle filtration to remove fine particles from all of the air that is supplied to the occupants is being used increasingly in the U.S. This chapter also presents an overview of the various types of ventilation systems found in homes and commercial office buildings and the common indoor air quality problems that may be associated with them. It also offers an overview of common HVAC evaluation techniques that can be used to determine if a ventilation system is performing in a manner that makes sense for the use of the space and the needs of the occupants. Are the occupants receiving a reasonable supply of outdoor air? Is the air that they receive of reasonable quality? Are obvious pollutants being exhausted? Ventilation systems have become extremely complex and more difficult to run and maintain over the past 40 years. This trend will continue to drive the need for professionally maintained HVAC equipment that is serviced and run by individuals who are accountable for the quality of the air that the system delivers.

A demonstration of NIOSH push-pull ventilation criteria.

PubMed

Klein, M K

1987-03-01

This paper summarizes the results of a study performed on an actual chrome plating tank in order to validate criteria for push-pull ventilation systems developed by Huebener and Hughes at NIOSH. Validation of the criteria was made by taking area industrial hygiene samples for hexavalent and total chrome at ten locations around the plating tank. The sampling was performed during actual production runs or while the tank was operating with a dummy load. The sampling data are summarized. The data show that the push-pull system, operating at Huebener's criteria, could control emissions to below the current standards and guidelines. Conclusions and recommendations are included.

The effect of electromagnetic interference from mobile communication on the performance of intensive care ventilators.

PubMed

Jones, R P; Conway, D H

2005-08-01

Electromagnetic interference produced by wireless communication can affect medical devices and hospital policies exist to address this risk. During the transfer of ventilated patients, these policies may be compromised by essential communication between base and receiving hospitals. Local wireless networks (e.g. Bluetooth) may reduce the 'spaghetti syndrome' of wires and cables seen on intensive care units, but also generate electromagnetic interference. The aim of this study was to investigate these effects on displayed and actual ventilator performance. Five ventilators were tested: Drager Oxylog 2000, BREAS LTV-1000, Respironics BiPAP VISION, Puritan Bennett 7200 and 840. Electromagnetic interference was generated by three devices: Simoco 8020 radio handset, Nokia 7210 and Nokia 6230 mobile phone, Nokia 6230 communicating via Bluetooth with a Palm Tungsten T Personal Digital Assistant. We followed the American National Standard Recommended Practice for On-Site, Ad Hoc Testing (ANSI C63) for electromagnetic interference. We used a ventilator tester, to simulate healthy adult lungs and measure ventilator performance. The communication device under test was moved in towards each ventilator from a distance of 1 m in six axes. Alarms or error codes on the ventilator were recorded, as was ventilator performance. All ventilators tested, except for the Respironics VISION, showed a display error when subjected to electromagnetic interference from the Nokia phones and Simoco radio. Ventilator performance was only affected by the radio which caused the Puritan Bennett 840 to stop functioning completely. The transfer ventilators' performance were not affected by radio or mobile phone, although the mobile phone did trigger a low-power alarm. Effects on intensive care ventilators included display reset, with the ventilator restoring normal display function within 2 s, and low-power/low-pressure alarms. Bluetooth transmission had no effect on the function of all the ventilators tested. In a clinical setting, high-power-output devices such as a two-way radio may cause significant interference in ventilator function. Medium-power-output devices such as mobile phones may cause minor alarm triggers. Low-power-output devices such as Bluetooth appear to cause no interference with ventilator function.

Modeled Effectiveness of Ventilation with Contaminant Control Devices on Indoor Air Quality in a Swine Farrowing Facility

PubMed Central

Anthony, T. Renée; Altmaier, Ralph; Park, Jae Hong; Peters, Thomas M.

2016-01-01

Because adverse health effects experienced by swine farm workers in concentrated animal feeding operations (CAFOs) have been associated with exposure to dust and gases, efforts to reduce exposures are warranted, particularly in winter seasons when exposures increase due to decreased ventilation. Simulation of air quality and operating costs for ventilating swine CAFO, including treating and recirculating air through a farrowing room, was performed using mass and energy balance equations over a 90-day winter season. System operation required controlling heater operation to achieve room temperatures optimal to ensure animal health (20 to 22.5°C). Five air pollution control devices, four room ventilation rates, and five recirculation patterns were examined. Inhalable dust concentrations were easily reduced using standard industrial air pollution control devices, including a cyclone, filtration, and electrostatic precipitator. Operating ventilation systems at 0.94 m3 s−1 (2000 cfm) with 75 to 100% recirculation of treated air from cyclone, electrostatic precipitator, and shaker dust filtration system achieves adequate particle control with operating costs under $1.00 per pig produced ($0.22 to 0.54), although carbon dioxide (CO2) concentrations approach 2000 ppm using in-room ventilated gas fired heaters. In no simulation were CO2 concentrations below industry recommended concentrations (1540 ppm), but alternative heating devices could reduce CO2 to acceptable concentrations. While this investigation does not represent all production swine farrowing barns, which differ in characteristics including room dimensions and swine occupancy, the simulation model and ventilation optimization methods can be applied to other production sites. This work shows that ventilation may be a cost-effective control option in the swine industry to reduce exposures. PMID:24433305

Modeled effectiveness of ventilation with contaminant control devices on indoor air quality in a swine farrowing facility.

PubMed

Anthony, T Renée; Altmaier, Ralph; Park, Jae Hong; Peters, Thomas M

2014-01-01

Because adverse health effects experienced by swine farm workers in concentrated animal feeding operations (CAFOs) have been associated with exposure to dust and gases, efforts to reduce exposures are warranted, particularly in winter seasons when exposures increase due to decreased ventilation. Simulation of air quality and operating costs for ventilating swine CAFO, including treating and recirculating air through a farrowing room, was performed using mass and energy balance equations over a 90-day winter season. System operation required controlling heater operation to achieve room temperatures optimal to ensure animal health (20 to 22.5 °C). Five air pollution control devices, four room ventilation rates, and five recirculation patterns were examined. Inhalable dust concentrations were easily reduced using standard industrial air pollution control devices, including a cyclone, filtration, and electrostatic precipitator. Operating ventilation systems at 0.94 m3 s(-1) (2000 cfm) with 75 to 100% recirculation of treated air from cyclone, electrostatic precipitator, and shaker dust filtration system achieves adequate particle control with operating costs under $1.00 per pig produced ($0.22 to 0.54), although carbon dioxide (CO2) concentrations approach 2000 ppm using in-room ventilated gas fired heaters. In no simulation were CO2 concentrations below industry recommended concentrations (1540 ppm), but alternative heating devices could reduce CO2 to acceptable concentrations. While this investigation does not represent all production swine farrowing barns, which differ in characteristics including room dimensions and swine occupancy, the simulation model and ventilation optimization methods can be applied to other production sites. This work shows that ventilation may be a cost-effective control option in the swine industry to reduce exposures.

The Influence of Internal Wall and Floor Covering Materials and Ventilation Type on Indoor Radon and Thoron Levels in Hospitals of Kermanshah, Iran.

PubMed

Pirsaheb, Meghdad; Najafi, Farid; Haghparast, Abbas; Hemati, Lida; Sharafi, Kiomars; Kurd, Nematullah

2016-10-01

Building materials and the ventilation rate of a building are two main factors influencing indoor radon and thoron levels (two radioactive gases which have the most important role in human natural radiation exposure within dwellings). This analytical descriptive study was intended to determine the relationship between indoor radon and thoron concentrations and the building materials used in interior surfaces, as well as between those concentrations and the type of ventilation system (natural or artificial). 102 measurements of radon and thoron levels were taken from different parts of three hospital buildings in the city of Kermanshah in the west of Iran, using an RTM-1688-2 radon meter. Information on the type of building material and ventilation system in the measurement location was collected and then analyzed using Stata 8 software and multivariate linear regression. In terms of radon and thoron emissions, travertine and plaster were found to be the most appropriate and inappropriate covering for walls, respectively. Furthermore, granite and travertine were discovered to be inappropriate materials for flooring, while plastic floor covering was found suitable. Natural ventilation performed better for radon, while artificial ventilation worked better for thoron. Internal building materials and ventilation type affect indoor radon and thoron concentrations. Therefore, the use of proper materials and adequate ventilation can reduce the potential human exposure to radon and thoron. This is of utmost importance, particularly in buildings with a high density of residents, including hospitals.

Numerical simulation of volume-controlled mechanical ventilated respiratory system with 2 different lungs.

PubMed

Shi, Yan; Zhang, Bolun; Cai, Maolin; Zhang, Xiaohua Douglas

2017-09-01

Mechanical ventilation is a key therapy for patients who cannot breathe adequately by themselves, and dynamics of mechanical ventilation system is of great significance for life support of patients. Recently, models of mechanical ventilated respiratory system with 1 lung are used to simulate the respiratory system of patients. However, humans have 2 lungs. When the respiratory characteristics of 2 lungs are different, a single-lung model cannot reflect real respiratory system. In this paper, to illustrate dynamic characteristics of mechanical ventilated respiratory system with 2 different lungs, we propose a mathematical model of mechanical ventilated respiratory system with 2 different lungs and conduct experiments to verify the model. Furthermore, we study the dynamics of mechanical ventilated respiratory system with 2 different lungs. This research study can be used for improving the efficiency and safety of volume-controlled mechanical ventilation system. Copyright © 2016 John Wiley & Sons, Ltd.

Differential lung ventilation via tracheostomy using two endotracheal tubes in an infant: a case report.

PubMed

Demirkol, Demet; Ataman, Yasemin; Gündoğdu, Gökhan

2017-09-08

This case report presents differential lung ventilation in an infant. The aim is to define an alternative technique for performing differential lung ventilation in children. To the best of our knowledge, this is the first report of this kind. A 4.2-kg, 2.5-month-old Asian boy was referred to our facility with refractory hypoxemia and hypercarbia due to asymmetric lung disease with atelectasis of the left lung and hyperinflation of the right lung. He was unresponsive to conventional ventilator strategies; different ventilator settings were required. To perform differential lung ventilation, two separate single-lumen endotracheal tubes were inserted into the main bronchus of each lung by tracheotomy; the tracheal tubes were attached to discrete ventilators. The left lung was ventilated with a lung salvage strategy using high-frequency oscillatory ventilation, and the right lung was ventilated with a lung-protective strategy using pressure-regulated volume control mode. Differential lung ventilation was performed successfully with this technique without complications. Differential lung ventilation may be a lifesaving procedure in select patients who have asymmetric lung disease. Inserting two single-lumen endotracheal tubes via tracheotomy for differential lung ventilation can be an effective and safe alternative method.

Effectiveness of a personalized ventilation system in reducing personal exposure against directly released simulated cough droplets.

PubMed

Pantelic, J; Tham, K W; Licina, D

2015-12-01

The inhalation intake fraction was used as an indicator to compare effects of desktop personalized ventilation and mixing ventilation on personal exposure to directly released simulated cough droplets. A cough machine was used to simulate cough release from the front, back, and side of a thermal manikin at distances between 1 and 4 m. Cough droplet concentration was measured with an aerosol spectrometer in the breathing zone of a thermal manikin. Particle image velocimetry was used to characterize the velocity field in the breathing zone. Desktop personalized ventilation substantially reduced the inhalation intake fraction compared to mixing ventilation for all investigated distances and orientations of the cough release. The results point out that the orientation between the cough source and the breathing zone of the exposed occupant is an important factor that substantially influences exposure. Exposure to cough droplets was reduced with increasing distance between cough source and exposed occupant. The results from this study show that an advanced air distribution system such as personalized ventilation reduces exposure to cough-released droplets better than commonly applied overhead mixing ventilation. This work can inform HVAC engineers about different aspects of air distribution systems’ performance and can serve as an aid in making critical design decisions. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Regional Lung Ventilation Analysis Using Temporally Resolved Magnetic Resonance Imaging.

PubMed

Kolb, Christoph; Wetscherek, Andreas; Buzan, Maria Teodora; Werner, René; Rank, Christopher M; Kachelrie, Marc; Kreuter, Michael; Dinkel, Julien; Heuel, Claus Peter; Maier-Hein, Klaus

We propose a computer-aided method for regional ventilation analysis and observation of lung diseases in temporally resolved magnetic resonance imaging (4D MRI). A shape model-based segmentation and registration workflow was used to create an atlas-derived reference system in which regional tissue motion can be quantified and multimodal image data can be compared regionally. Model-based temporal registration of the lung surfaces in 4D MRI data was compared with the registration of 4D computed tomography (CT) images. A ventilation analysis was performed on 4D MR images of patients with lung fibrosis; 4D MR ventilation maps were compared with corresponding diagnostic 3D CT images of the patients and 4D CT maps of subjects without impaired lung function (serving as reference). Comparison between the computed patient-specific 4D MR regional ventilation maps and diagnostic CT images shows good correlation in conspicuous regions. Comparison to 4D CT-derived ventilation maps supports the plausibility of the 4D MR maps. Dynamic MRI-based flow-volume loops and spirograms further visualize the free-breathing behavior. The proposed methods allow for 4D MR-based regional analysis of tissue dynamics and ventilation in spontaneous breathing and comparison of patient data. The proposed atlas-based reference coordinate system provides an automated manner of annotating and comparing multimodal lung image data.

Performance and Life Tests of a Regenerative Blower for EVA Suit Ventilation

NASA Technical Reports Server (NTRS)

Izenson, Mike; Chen, Weibo; Paul, Heather L.; Jennings, Mallory A.

2011-01-01

Ventilation fans for future space suits must meet demanding performance specifications, satisfy stringent safety requirements for operation in an oxygen atmosphere, and be able to increase output to operate in buddy mode. A regenerative blower is an attractive choice due to its ability to meet these requirements at low operating speed. This paper describes progress in the development and testing of a regenerative blower designed to meet requirements for ventilation subsystems in a future space suit Portable Life Support Systems (PLSS). The blower assembly includes a custom-designed motor that has significantly improved in efficiency during this development effort. The blower was tested at both nominal and buddy mode operating points and head/flow performance and power consumption were measured. The blower was operated for over 1000 hours to demonstrate safe operation in an oxygen test loop at prototypical pressures. In addition, the blower demonstrated operation with the introduction of simulated lunar dust.

SY Tank Farm ventilation isolation option risk assessment report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Powers, T.B.; Morales, S.D.

The safety of the 241-SY Tank Farm ventilation system has been under extensive scrutiny due to safety concerns associated with tank 101-SY. Hydrogen and other gases are generated and trapped in the waste below the liquid surface. Periodically, these gases are released into the dome space and vented through the exhaust system. This attention to the ventilation system has resulted in the development of several alternative ventilation system designs. The ventilation system provides the primary means of mitigation of accidents associated with flammable gases. This report provides an assessment of various alternatives ventilation system designs.

Numerical analysis of natural ventilation system in a studio apartment in Bangladesh

NASA Astrophysics Data System (ADS)

Kabir, K. M. Ariful; Hasan, Md. Rakibul; Khan, Md. Abdul Hakim

2017-07-01

The study of temperature and air flow for natural ventilation system has been investigated numerically. A finite element model for studio apartment was developed with the aim of achieving detail energy allocation in the real buildings during the transient process in the walls and internal air. A tool of computational fluid dynamics (CFD) is employed to assist the process. In the tropical regions most of the energy is consumed by the heating, cooling and ventilation appliances. Therefore, the optimize ventilation system will be a suitable and valid option for the saving of energy from the household sector to increase cooling performance and ensuring thermal comfort as well. A mathematical exploration is carried out on full scale dwelling and small scale model and indication is given on the relevance of such a comparison. Calculations are carried out with household heat sources for calm and windy period, but without any human. As expected, for windy periods, the wind is the main driving force behind the internal air flow. However, in calm periods for unsteady flow the internal airflow looks like more complexes through observation.

Multi-Objectives Optimization of Ventilation Controllers for Passive Cooling in Residential Buildings

PubMed Central

Grygierek, Krzysztof; Ferdyn-Grygierek, Joanna

2018-01-01

An inappropriate indoor climate, mostly indoor temperature, may cause occupants’ discomfort. There are a great number of air conditioning systems that make it possible to maintain the required thermal comfort. Their installation, however, involves high investment costs and high energy demand. The study analyses the possibilities of limiting too high a temperature in residential buildings using passive cooling by means of ventilation with ambient cool air. A fuzzy logic controller whose aim is to control mechanical ventilation has been proposed and optimized. In order to optimize the controller, the modified Multiobjective Evolutionary Algorithm, based on the Strength Pareto Evolutionary Algorithm, has been adopted. The optimization algorithm has been implemented in MATLAB®, which is coupled by MLE+ with EnergyPlus for performing dynamic co-simulation between the programs. The example of a single detached building shows that the occupants’ thermal comfort in a transitional climate may improve significantly owing to mechanical ventilation controlled by the suggested fuzzy logic controller. When the system is connected to the traditional cooling system, it may further bring about a decrease in cooling demand. PMID:29642525

Evaluation of manual and automatic manually triggered ventilation performance and ergonomics using a simulation model.

PubMed

Marjanovic, Nicolas; Le Floch, Soizig; Jaffrelot, Morgan; L'Her, Erwan

2014-05-01

In the absence of endotracheal intubation, the manual bag-valve-mask (BVM) is the most frequently used ventilation technique during resuscitation. The efficiency of other devices has been poorly studied. The bench-test study described here was designed to evaluate the effectiveness of an automatic, manually triggered system, and to compare it with manual BVM ventilation. A respiratory system bench model was assembled using a lung simulator connected to a manikin to simulate a patient with unprotected airways. Fifty health-care providers from different professional groups (emergency physicians, residents, advanced paramedics, nurses, and paramedics; n = 10 per group) evaluated manual BVM ventilation, and compared it with an automatic manually triggered device (EasyCPR). Three pathological situations were simulated (restrictive, obstructive, normal). Standard ventilation parameters were recorded; the ergonomics of the system were assessed by the health-care professionals using a standard numerical scale once the recordings were completed. The tidal volume fell within the standard range (400-600 mL) for 25.6% of breaths (0.6-45 breaths) using manual BVM ventilation, and for 28.6% of breaths (0.3-80 breaths) using the automatic manually triggered device (EasyCPR) (P < .0002). Peak inspiratory airway pressure was lower using the automatic manually triggered device (EasyCPR) (10.6 ± 5 vs 15.9 ± 10 cm H2O, P < .001). The ventilation rate fell consistently within the guidelines, in the case of the automatic manually triggered device (EasyCPR) only (10.3 ± 2 vs 17.6 ± 6, P < .001). Significant pulmonary overdistention was observed when using the manual BVM device during the normal and obstructive sequences. The nurses and paramedics considered the ergonomics of the automatic manually triggered device (EasyCPR) to be better than those of the manual device. The use of an automatic manually triggered device may improve ventilation efficiency and decrease the risk of pulmonary overdistention, while decreasing the ventilation rate.

Technology Solutions Case Study: Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

DOE Office of Scientific and Technical Information (OSTI.GOV)

A. Rudd and D. Bergey

Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, andmore » filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs.« less

A knowledge-based support system for mechanical ventilation of the lungs. The KUSIVAR concept and prototype.

PubMed

Rudowski, R; Frostell, C; Gill, H

1989-09-01

The KUSIVAR is an expert system for mechanical ventilation of adult patients suffering from respiratory insufficiency. Its main objective is to provide guidance in respirator management. The knowledge base includes both qualitative, rule-based knowledge and quantitative knowledge expressed in the form of mathematical models (expert control) which is used for prediction of arterial gas tensions and optimization purposes. The system is data driven and uses a forward chaining mechanism for rule invocation. The interaction with the user will be performed in advisory, critiquing, semi-automatic and automatic modes. The system is at present in an advanced prototype stage. Prototyping is performed using KEE (Knowledge Engineering Environment) on a Sperry Explorer workstation. For further development and clinical use the expert system will be downloaded to an advanced PC. The system is intended to support therapy with a Siemens-Elema Servoventilator 900 C.

Building America Case Study: Ventilation System Effectiveness and Tested Indoor Air Quality Impacts, Tyler, Texas

DOE Office of Scientific and Technical Information (OSTI.GOV)

?Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, andmore » filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy.« less

Mobile communication devices causing interference in invasive and noninvasive ventilators.

PubMed

Dang, Bao P; Nel, Pierre R; Gjevre, John A

2007-06-01

The aim of this study was to assess if common mobile communication systems would cause significant interference on mechanical ventilation devices and at what distances would such interference occur. We tested all the invasive and noninvasive ventilatory devices used within our region. This consisted of 2 adult mechanical ventilators, 1 portable ventilator, 2 pediatric ventilators, and 2 noninvasive positive pressure ventilatory devices. We operated the mobile devices from the 2 cellular communication systems (digital) and 1 2-way radio system used in our province at varying distances from the ventilators and looked at any interference they created. We tested the 2-way radio system, which had a fixed operation power output of 3.0 watts, the Global Systems for Mobile Communication cellular system, which had a maximum power output of 2.0 watts and the Time Division Multiple Access cellular system, which had a maximum power output of 0.2 watts on our ventilators. The ventilators were ventilating a plastic lung at fixed settings. The mobile communication devices were tested at varying distances starting at zero meter from the ventilator and in all operation modes. The 2-way radio caused the most interference on some of the ventilators, but the maximum distance of interference was 1.0 m. The Global Systems for Mobile Communication system caused significant interference only at 0 m and minor interference at 0.5 m on only 1 ventilator. The Time Division Multiple Access system caused no interference at all. Significant interference consisted of a dramatic rise and fluctuation of the respiratory rate, pressure, and positive end-expiratory pressure of the ventilators with no normalization when the mobile device was removed. From our experiment on our ventilators with the communication systems used in our province, we conclude that mobile communication devices such as cellular phones and 2-way radios are safe and cause no interference unless operated at very close distances of less than 1 meter.

Analysis of radon reduction and ventilation systems in uranium mines in China.

PubMed

Hu, Peng-hua; Li, Xian-jie

2012-09-01

Mine ventilation is the most important way of reducing radon in uranium mines. At present, the radon and radon progeny levels in Chinese uranium mines where the cut and fill stoping method is used are 3-5 times higher than those in foreign uranium mines, as there is not much difference in the investments for ventilation protection between Chinese uranium mines and international advanced uranium mines with compaction methodology. In this paper, through the analysis of radon reduction and ventilation systems in Chinese uranium mines and the comparison of advantages and disadvantages between a variety of ventilation systems in terms of radon control, the authors try to illustrate the reasons for the higher radon and radon progeny levels in Chinese uranium mines and put forward some problems in three areas, namely the theory of radon control and ventilation systems, radon reduction ventilation measures and ventilation management. For these problems, this paper puts forward some proposals regarding some aspects, such as strengthening scrutiny, verifying and monitoring the practical situation, making clear ventilation plans, strictly following the mining sequence, promoting training of ventilation staff, enhancing ventilation system management, developing radon reduction ventilation technology, purchasing ventilation equipment as soon as possible in the future, and so on.

Technical Note: A proposal of air ventilation system design criteria for a clinical room in a heavy-ion medical facility.

PubMed

Kum, Oyeon

2018-06-01

An optimized air ventilation system design for a treatment room in Heavy-ion Medical Facility is an important issue in the aspects of nuclear safety because the activated air produced in a treatment room can directly affect the medical staff and the general public in the radiation-free area. Optimized design criteria of air ventilation system for a clinical room in 430 MeV/u carbon ion beam medical accelerator facility was performed by using a combination of MCNPX2.7.0 and CINDER'90 codes. Effective dose rate and its accumulated effective dose by inhalation and residual gamma were calculated for a normal treatment scenario (2 min irradiation for one fraction) as a function of decay time. Natural doses around the site were measured before construction and used as reference data. With no air ventilation system, the maximum effective dose rate was about 3 μSv/h (total dose of 90 mSv/y) and minimum 0.2 μSv/h (total dose of 6 mSv/y), which are over the legal limits for medical staff and for the general public. Although inhalation dose contribution was relatively small, it was considered seriously because of its long-lasting effects in the body. The integrated dose per year was 1.8 mSv/y in the radiation-free area with the 20-min rate of air ventilation system. An optimal air ventilation rate of 20 min is proposed for a clinical room, which also agrees with the best mechanical design value. © 2018 American Association of Physicists in Medicine.

Pressure Dynamic Characteristics of Pressure Controlled Ventilation System of a Lung Simulator

PubMed Central

Shi, Yan; Ren, Shuai; Cai, Maolin; Xu, Weiqing; Deng, Qiyou

2014-01-01

Mechanical ventilation is an important life support treatment of critically ill patients, and air pressure dynamics of human lung affect ventilation treatment effects. In this paper, in order to obtain the influences of seven key parameters of mechanical ventilation system on the pressure dynamics of human lung, firstly, mechanical ventilation system was considered as a pure pneumatic system, and then its mathematical model was set up. Furthermore, to verify the mathematical model, a prototype mechanical ventilation system of a lung simulator was proposed for experimental study. Last, simulation and experimental studies on the air flow dynamic of the mechanical ventilation system were done, and then the pressure dynamic characteristics of the mechanical system were obtained. The study can be referred to in the pulmonary diagnostics, treatment, and design of various medical devices or diagnostic systems. PMID:25197318

Styrene vapor control systems in FRP yacht plants.

PubMed

Todd, W F

1985-01-01

The production of large (greater than 25-ft) fiber-reinforced plastic (FRP) yachts has presented problems of styrene exposure in excess of the Occupational Safety and Health Administration permissible exposure level (OSHA PEL) of 100 ppm. Also, the National Institute for Occupational Safety and Health (NIOSH) is currently recommending a 10-hour workshift, 40-hour workweek time weighted average (TWA) of 50 ppm for styrene. Meeting this challenge will require a system of engineering, work practice, personal protective equipment, and monitoring control measures. NIOSH has performed a study of the engineering controls in three FRP yacht plants. Work practices and the use of personal protective equipment (PPE) were also considered in the evaluation. The three systems evaluated included a dilution system, a local ventilation system, and a push-pull ventilation system. The cost of constructing and operating these systems was not evaluated in this study. Study results indicated that each type of ventilation system can meet the present PEL of 100 ppm styrene; however, it is not certain that these systems can meet a lower PEL of 50 ppm styrene.

Inventory of a Neurological Intensive Care Unit: Who Is Treated and How Long?

PubMed Central

Backhaus, Roland; Aigner, Franz; Steffling, Dagmar; Jakob, Wolfgang; Steinbrecher, Andreas; Kaiser, Bernhard; Hau, Peter; Boy, Sandra; Fuchs, Kornelius; Bogdahn, Ulrich; Ritzka, Markus

2015-01-01

Purpose. To characterize indications, treatment, and length of stay in a stand-alone neurological intensive care unit with focus on comparison between ventilated and nonventilated patient. Methods. We performed a single-center retrospective cohort study of all treated patients in our neurological intensive care unit between October 2006 and December 2008. Results. Overall, 512 patients were treated in the surveyed period, of which 493 could be included in the analysis. Of these, 40.8% had invasive mechanical ventilation and 59.2% had not. Indications in both groups were predominantly cerebrovascular diseases. Length of stay was 16.5 days in mean for ventilated and 3.6 days for nonventilated patient. Conclusion. Most patients, ventilated or not, suffer from vascular diseases with further impairment of other organ systems or systemic complications. Data reflects close relationship and overlap of treatment on nICU with a standardized stroke unit treatment and suggests, regarding increasing therapeutic options, the high impact of acute high-level treatment to reduce consequential complications. PMID:26199757

Impact of ventilation systems and energy savings in a building on the mechanisms governing the indoor radon activity concentration.

PubMed

Collignan, Bernard; Powaga, Emilie

2017-11-23

For a given radon potential in the ground and a given building, the parameters affecting the indoor radon activity concentration (IRnAC) are indoor depressurization of a building and its air change rate. These parameters depend mainly on the building characteristics, such as airtightness, and on the nature and performances of the ventilation system. This study involves a numerical sensitivity assessment of the indoor environmental conditions on the IRnAC in buildings. A numerical ventilation model has been adapted to take into account the effects of variations in the indoor environmental conditions (depressurization and air change rate) on the radon entry rate and on the IRnAC. In the context of the development of a policy to reduce energy consumption in a building, the results obtained showed that IRnAC could be strongly affected by variations in the air permeability of the building associated with the ventilation regime. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudd, Armin; Bergey, Daniel

In this project, Building America research team Building Science Corporation tested the effectiveness of ventilation systems at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. This was because the sourcemore » of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four system factor categories: balance, distribution, outside air source, and recirculation filtration. Recommended system factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.« less

Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudd, Armin; Bergey, Daniel

Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. It was inferior because the source of outside air was not direct from outside, themore » ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.« less

The Influence of Internal Wall and Floor Covering Materials and Ventilation Type on Indoor Radon and Thoron Levels in Hospitals of Kermanshah, Iran

PubMed Central

Pirsaheb, Meghdad; Najafi, Farid; Haghparast, Abbas; Hemati, Lida; Sharafi, Kiomars; Kurd, Nematullah

2016-01-01

Background Building materials and the ventilation rate of a building are two main factors influencing indoor radon and thoron levels (two radioactive gases which have the most important role in human natural radiation exposure within dwellings). Objectives This analytical descriptive study was intended to determine the relationship between indoor radon and thoron concentrations and the building materials used in interior surfaces, as well as between those concentrations and the type of ventilation system (natural or artificial). Materials and Methods 102 measurements of radon and thoron levels were taken from different parts of three hospital buildings in the city of Kermanshah in the west of Iran, using an RTM-1688-2 radon meter. Information on the type of building material and ventilation system in the measurement location was collected and then analyzed using Stata 8 software and multivariate linear regression. Results In terms of radon and thoron emissions, travertine and plaster were found to be the most appropriate and inappropriate covering for walls, respectively. Furthermore, granite and travertine were discovered to be inappropriate materials for flooring, while plastic floor covering was found suitable. Natural ventilation performed better for radon, while artificial ventilation worked better for thoron. Conclusions Internal building materials and ventilation type affect indoor radon and thoron concentrations. Therefore, the use of proper materials and adequate ventilation can reduce the potential human exposure to radon and thoron. This is of utmost importance, particularly in buildings with a high density of residents, including hospitals. PMID:28180013

Analysis of the systems of ventilation of residential houses of Ukraine and Estonia

NASA Astrophysics Data System (ADS)

Savchenko, Olena; Zhelykh, Vasyl; Voll, Hendrik

2017-12-01

The most common ventilation system in residential buildings in Ukraine is natural ventilation. In recent years, due to increased tightness of structures, an increase in the content of synthetic finishing materials in them, the quality of microclimate parameters deteriorated. One of the measures to improve the parameters of indoor air in residential buildings is the use of mechanical inflow and exhaust ventilation system. In this article the regulatory documents concerning the design of ventilation systems in Ukraine and Estonia and the requirements for air exchange in residential buildings are considered. It is established that the existing normative documents in Ukraine are analogous to European norms, which allow design the system of ventilation of residential buildings according to European standards. However, the basis for the design of ventilation systems in Ukraine is the national standards, in which mechanical ventilation, unfortunately, is provided only for the design of high-rise buildings. To maintain acceptable microclimate parameters in residential buildings, it is advisable for designers to apply the requirements for designing ventilation systems in accordance with European standards.

Impact of surface disinfection and sterile draping of furniture on room air quality in a cardiac procedure room with a ventilation and air-conditioning system (extrusion airflow, cleanroom class 1b (DIN 1946-4)).

PubMed

Below, Harald; Ryll, Sylvia; Empen, Klaus; Dornquast, Tina; Felix, Stefan; Rosenau, Heike; Kramer, Sebastian; Kramer, Axel

2010-09-21

In a cardiac procedure room, ventilated by a ventilation and air-conditioning system with turbulent mixed airflow, a protection zone in the operating area could be defined through visualization of airflows. Within this protection zone, no turbulence was detectable in the room air.Under the given conditions, disinfection of all surfaces including all furniture and equipment after the last operation and subsequent draping of furniture and all equipment that could not be removed from the room with sterile surgical drapes improved the indoor room air quality from cleanroom class C to cleanroom class B. This also allows procedures with elevated requirements to be performed in room class 1b.

Automated ventilator testing.

PubMed

Ghaly, J; Smith, A L

1994-06-01

A new era has arrived for the Biomedical Engineering Department at the Royal Women's Hospital in Melbourne. We have developed a system to qualitatively test for intermittent or unconfirmed faults, associated with Bear Cub ventilators. Where previous testing has been inadequate, computer logging is now used to interface the RT200 Timeter Calibration Analyser (TCA) to obtain a real time display of data, which can be stored and graphed. Using Quick Basic version 4.5, it was possible to establish communication between the TCA and an IBM compatible computer, such that meaningful displays of machine performance were produced. From the parameters measured it has been possible to obtain data on Peak Pressure, Inspiratory to Expiratory ratio (I:E ratio) Peak Flow and Rate. Monitoring is not limited to these parameters, though these were selected for our particular needs. These parameters are plotted in two ways: 1. Compressed average versus time, up to 24 hours on one screen 2. Raw data, 36 minutes displayed on each screen. The compressed data gives an overview which allows easy identification of intermittent faults. The uncompressed data confirms that the averaged signal is a realistic representation of the situation. One of the major benefits of this type of data analysis, is that ventilator performance may be monitored over a long period of time without requiring the presence of a service technician. It also allows individual ventilator performance to be graphically compared to other ventilators.

Occupational exposure to nitrous oxide - the role of scavenging and ventilation systems in reducing the exposure level in operating rooms.

PubMed

Krajewski, Wojciech; Kucharska, Malgorzata; Wesolowski, Wiktor; Stetkiewicz, Jan; Wronska-Nofer, Teresa

2007-03-01

The aim of this study was to assess the level of occupational exposure to nitrous oxide (N(2)O) in operating rooms (ORs), as related to different ventilation and scavenging systems used to remove waste anaesthetic gases from the work environment. The monitoring of N(2)O in the air covered 35 ORs in 10 hospitals equipped with different systems for ventilation and anaesthetic scavenging. The examined systems included: natural ventilation with supplementary fresh air provided by a pressure ventilation system (up to 6 air changes/h); pressure and exhaust ventilation systems equipped with ventilation units supplying fresh air to and discharging contaminated air outside the working area (more than 10 air changes/h); complete air-conditioning system with laminar air flow (more than 15 air changes/h). The measurements were carried out during surgical procedures (general anaesthesia induced intravenously and maintained with inhaled N(2)O and sevofluran delivered through cuffed endotracheal tubes) with connected or disconnected air scavenging. Air was collected from the breathing zone of operating personnel continuously through the whole time of anaesthesia to Tedlar((R)) bags, and N(2)O concentrations in air samples were analyzed by adsorption gas chromatography/mass spectrometry. N(2)O levels in excess of the occupational exposure limit (OEL) value of 180mg/m(3) were registered in all ORs equipped with ventilation systems alone. The OEL value was exceeded several times in rooms with natural ventilation plus supplementary pressure ventilations and twice or less in those with pressure/exhaust ventilation systems or air conditioning. N(2)O levels below or within the OEL value were observed in rooms where the system of air conditioning or pressure/exhaust ventilation was combined with scavenging systems. Systems combining natural/pressure ventilation with scavenging were inadequate to maintain N(2)O concentration below the OEL value. Air conditioning and an efficient pressure/exhaust ventilation (above 12 air exchanges/h) together with efficient active scavenging systems are sufficient to sustain N(2)O exposure in ORs at levels below or within the OEL value of 180mg/m(3).

Engine Performance (Section C: Emission Control Systems). Auto Mechanics Curriculum Guide. Module 3. Instructor's Guide.

ERIC Educational Resources Information Center

Rains, Larry

This engine performance (emission control systems) module is one of a series of competency-based modules in the Missouri Auto Mechanics Curriculum Guide. Topics of this module's five units are: positive crankcase ventilation (PCV) and evaporative emission control systems; exhaust gas recirculation (EGR); air injection and catalytic converters;…

46 CFR 153.312 - Ventilation system standards.

Code of Federal Regulations, 2013 CFR

2013-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.312 Ventilation system standards. A cargo handling space ventilation... (approx. 32.8 ft) from openings into or ventilation intakes for, accommodation or service spaces. (b) A...

46 CFR 153.312 - Ventilation system standards.

Code of Federal Regulations, 2012 CFR

2012-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.312 Ventilation system standards. A cargo handling space ventilation... (approx. 32.8 ft) from openings into or ventilation intakes for, accommodation or service spaces. (b) A...

46 CFR 153.312 - Ventilation system standards.

Code of Federal Regulations, 2011 CFR

2011-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.312 Ventilation system standards. A cargo handling space ventilation... (approx. 32.8 ft) from openings into or ventilation intakes for, accommodation or service spaces. (b) A...

46 CFR 153.312 - Ventilation system standards.

Code of Federal Regulations, 2014 CFR

2014-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.312 Ventilation system standards. A cargo handling space ventilation... (approx. 32.8 ft) from openings into or ventilation intakes for, accommodation or service spaces. (b) A...

46 CFR 153.312 - Ventilation system standards.

Code of Federal Regulations, 2010 CFR

2010-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.312 Ventilation system standards. A cargo handling space ventilation... (approx. 32.8 ft) from openings into or ventilation intakes for, accommodation or service spaces. (b) A...

Using a Ventilation Controller to Optimize Residential Passive Ventilation For Energy and Indoor Air Quality

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turner, William; Walker, Iain

One way to reduce the energy impact of providing residential ventilation is to use passive and hybrid systems. However, these passive and hybrid (sometimes called mixed-mode) systems must still meet chronic and acute health standards for ventilation. This study uses a computer simulation approach to examine the energy and indoor air quality (IAQ) implications of passive and hybrid ventilation systems, in 16 California climate zones. Both uncontrolled and flow controlled passive stacks are assessed. A new hybrid ventilation system is outlined that uses an intelligent ventilation controller to minimise energy use, while ensuring chronic and acute IAQ standards are met.more » ASHRAE Standard 62.2-2010 – the United States standard for residential ventilation - is used as the chronic standard, and exposure limits for PM 2.5, formaldehyde and NO 2 are used as the acute standards.The results show that controlled passive ventilation and hybrid ventilation can be used in homes to provide equivalent IAQ to continuous mechanical ventilation, for less use of energy.« less

Clinical Practice Guideline of Acute Respiratory Distress Syndrome

PubMed Central

Cho, Young-Jae; Moon, Jae Young; Shin, Ein-Soon; Kim, Je Hyeong; Jung, Hoon; Park, So Young; Kim, Ho Cheol; Sim, Yun Su; Rhee, Chin Kook; Lim, Jaemin; Lee, Seok Jeong; Lee, Won-Yeon; Lee, Hyun Jeong; Kwak, Sang Hyun; Kang, Eun Kyeong; Chung, Kyung Soo

2016-01-01

There is no well-stated practical guideline for mechanically ventilated patients with or without acute respiratory distress syndrome (ARDS). We generate strong (1) and weak (2) grade of recommendations based on high (A), moderate (B) and low (C) grade in the quality of evidence. In patients with ARDS, we recommend low tidal volume ventilation (1A) and prone position if it is not contraindicated (1B) to reduce their mortality. However, we did not support high-frequency oscillatory ventilation (1B) and inhaled nitric oxide (1A) as a standard treatment. We also suggest high positive end-expiratory pressure (2B), extracorporeal membrane oxygenation as a rescue therapy (2C), and neuromuscular blockage for 48 hours after starting mechanical ventilation (2B). The application of recruitment maneuver may reduce mortality (2B), however, the use of systemic steroids cannot reduce mortality (2B). In mechanically ventilated patients, we recommend light sedation (1B) and low tidal volume even without ARDS (1B) and suggest lung protective ventilation strategy during the operation to lower the incidence of lung complications including ARDS (2B). Early tracheostomy in mechanically ventilated patients can be performed only in limited patients (2A). In conclusion, of 12 recommendations, nine were in the management of ARDS, and three for mechanically ventilated patients. PMID:27790273

Optimization of Ventilation Energy Demands and Indoor Air Quality in High-Performance Homes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hun, Diana E; Jackson, Mark C; Shrestha, Som S

2014-01-01

High-performance homes require that ventilation energy demands and indoor air quality (IAQ) be simultaneously optimized. We attempted to bridge these two areas by conducting tests in a research house located in Oak Ridge, TN, that was 20 months old, energy-efficient (i.e., expected to consume 50% less energy than a house built per the 2006 IRC), tightly-built (i.e., natural ventilation rate ~0.02 h-1), unoccupied, and unfurnished. We identified air pollutants of concern in the test home that could generally serve as indicators of IAQ, and conduced field experiments and computer simulations to determine the effectiveness and energy required by various techniquesmore » that lessened the concentration of these contaminants. Formaldehyde was selected as the main pollutant of concern among the contaminants that were sampled in the initial survey because it was the only compound that showed concentrations that were greater than the recommended exposure levels. Field data indicate that concentrations were higher during the summer primarily because emissions from sources rise with increases in temperature. Furthermore, supply ventilation and gas-phase filtration were effective means to reduce formaldehyde concentrations; however, exhaust ventilation had minimal influence on this pollutant. Results from simulations suggest that formaldehyde concentrations obtained while ventilating per ASHRAE 62.2-2010 could be decreased by about 20% from May through September through three strategies: 1) increasing ASHRAE supply ventilation by a factor of two, 2) reducing the thermostat setpoint from 76 to 74 F, or 3) running a gas-phase filtration system while decreasing supply ventilation per ASHRAE by half. In the mixed-humid climate of Oak Ridge, these strategies caused increases in electricity cost of ~$5 to ~$15/month depending on outdoor conditions.« less

Aerobiology in the operating room and its implications for working standards.

PubMed

Friberg, B; Friberg, S

2005-01-01

Two novel operating room (OR) ventilation concepts, i.e. the upward displacement or thermal convection system and the exponential ultra-clean laminar air flow (LAF) designed to function without extra walls, were evaluated from a bacteriological point of view. The thermal convection system (17 air changes/h) was compared with conventional ventilation (16 air changes/h) with an air inlet at the ceiling and evacuation at floor level. The exponential LAF was compared with the vertical ultra-clean LAF and the horizontal ultra-clean LAF, both with extra side walls. The comparison was made using strictly standardized simulated operations and, except for the horizontal LAF, it was performed in the same OR where the type of ventilation was changed. In the different areas important for surgical asepsis, the thermal system resulted in a twofold to threefold increase in bacterial air and surface counts compared to the conventional system (statistical significance = p < 0.05-0.0001). The bacteriological efficiency of the exponential LAF was equal to the horizontal and vertical LAF units with extra walls in the OR, and all three systems easily fulfilled the criteria for ultra-clean air, i.e. bacteria-carrying particles < 10/m3. In the areas important for surgical asepsis the turbulent ventilation systems yielded highly significant correlation between air and surface contamination (p < 0.02-0.0006). No such correlation existed in the LAF systems.

Spacesuit Portable Life Support System Breadboard (PLSS 1.0) Development and Test Results

NASA Technical Reports Server (NTRS)

Vogel, Matt R.; Watts, Carly

2011-01-01

A multi-year effort has been carried out at NASA-JSC to develop an advanced Extravehicular Activity (EVA) PLSS design intended to further the current state of the art by increasing operational flexibility, reducing consumables, and increasing robustness. Previous efforts have focused on modeling and analyzing the advanced PLSS architecture, as well as developing key enabling technologies. Like the current International Space Station (ISS) Extravehicular Mobility Unit (EMU) PLSS, the advanced PLSS comprises of three subsystems required to sustain the crew during EVA including the Thermal, Ventilation, and Oxygen Subsystems. This multi-year effort has culminated in the construction and operation of PLSS 1.0, a test rig that simulates full functionality of the advanced PLSS design. PLSS 1.0 integrates commercial off the shelf hardware with prototype technology development components, including the primary and secondary oxygen regulators, ventilation loop fan, Rapid Cycle Amine (RCA) swingbed, and Spacesuit Water Membrane Evaporator (SWME). Testing accumulated 239 hours over 45 days, while executing 172 test points. Specific PLSS 1.0 test objectives assessed during this testing include: confirming key individual components perform in a system level test as they have performed during component level testing; identifying unexpected system-level interactions; operating PLSS 1.0 in nominal steady-state EVA modes to baseline subsystem performance with respect to metabolic rate, ventilation loop pressure and flow rate, and environmental conditions; simulating nominal transient EVA operational scenarios; simulating contingency EVA operational scenarios; and further evaluating individual technology development components. Successful testing of the PLSS 1.0 provided a large database of test results that characterize system level and component performance. With the exception of several minor anomalies, the PLSS 1.0 test rig performed as expected; furthermore, many system responses trended in accordance with pre-test predictions.

[Ventilation during cardiopulmonary resuscitation in the infant. Mouth to mouth and nose, or bag-valve-mask? A quasi-experimental study].

PubMed

Santos-Folgar, Myriam; Otero-Agra, Martín; Fernández-Méndez, Felipe; Hermo-Gonzalo, María Teresa; Barcala-Furelos, Roberto; Rodríguez-Núñez, Antonio

2018-02-08

It has been observed that health professionals have difficulty performing quality cardiopulmonary resuscitation (CPR). The aim of this study was to compare the quality of ventilations performed by Nursing students on an infant model using different methods (mouth-to-mouth-and-nose or bag-valve-mask). A quasi-experimental cross-sectional study was performed that included 46 second-year Nursing students. Two quantitative 4-minute tests of paediatric CPR were performed: a) mouth-to-mouth-and-nose ventilations, and b) ventilations with bag-valve-mask. A Resusci Baby QCPR Wireless SkillReporter® mannequin from Laerdal was used. The proportion of ventilations with adequate, excessive, and insufficient volume was recorded and analysed, as well as the overall quality of the CPR (ventilations and chest compressions). The students were able to give a higher number of ventilations with adequate volume using the mouth-to-mouth-and-nose method (55±22%) than with the bag-valve-mask (28±16%, P<.001). The overall quality of the CPR was also significantly higher when using the mouth-to-mouth-and-nose method (60±19 vs. 48±16%, P<.001). Mouth-to-mouth-and-nose ventilation method is more efficient than bag-valve-mask ventilations in CPR performed by nursing students with a simulated infant model. Copyright © 2018. Publicado por Elsevier España, S.L.U.

Crew Survivability After a Rapid Cabin Depressurization Event

NASA Technical Reports Server (NTRS)

Sargusingh, Miriam J.

2012-01-01

Anecdotal evidence acquired through historic failure investigations involving rapid cabin decompression (e.g. Challenger, Columbia and Soyuz 11) show that full evacuation of the cabin atmosphere may occur within seconds. During such an event, the delta-pressure between the sealed suit ventilation system and the cabin will rise at the rate of the cabin depressurization; potentially at a rate exceeding the capability of the suit relief valve. It is possible that permanent damage to the suit pressure enclosure and ventilation loop components may occur as the integrated system may be subjected to delta pressures in excess of the design-to pressures. Additionally, as the total pressure of the suit ventilation system decreases, so does the oxygen available to the crew. The crew may be subjected to a temporarily incapacitating, but non-lethal, hypoxic environment. It is expected that the suit will maintain a survivable atmosphere on the crew until the vehicle pressure control system recovers or the cabin has otherwise attained a habitable environment. A common finding from the aforementioned reports indicates that the crew would have had a better chance at surviving the event had they been in a protective configuration, that is, in a survival suit. Making use of these lessons learned, the Constellation Program implemented a suit loop in the spacecraft design and required that the crew be in a protective configuration, that is suited with gloves on and visors down, during dynamic phases of flight that pose the greatest risk for a rapid and uncontrolled cabin depressurization event: ascent, entry, and docking. This paper details the evaluation performed to derive suit pressure garment and ventilation system performance parameters that would lead to the highest probability of crew survivability after an uncontrolled crew cabin depressurization event while remaining in the realm of practicality for suit design. This evaluation involved: (1) assessment of stakeholder expectations to validate the functionality being imposed; (2) review/refinement of concept of operations to establish the potential triggers for such an event and define the response of the spacecraft and suit ventilation loop pressure control systems; and (3) assessment of system capabilities with respect to structural capability and pressure control.

Columbia County Habitat for Humanity Passive Townhomes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dentz, Jordan; Alaigh, Kunal; Dadia, Devanshi

2016-03-18

Columbia County (New York) Habitat for Humanity built a pair of townhomes to Passive House criteria with the purpose of exploring approaches for achieving Passive House performance and to eventually develop a prototype design for future projects. The project utilized a 2x6 frame wall with a structural insulated panel curtain wall and a ventilated attic over a sealed OSB ceiling air barrier. Mechanical systems include a single head, wall mounted ductless mini-split heat pump in each unit and a heat recovery ventilator. Costs were $26,000 per unit higher for Passive House construction compared with the same home built to ENERGYmore » STAR version 3 specifications, representing about 18% of total construction cost. This report discusses the cost components, energy modeling results and lessons from construction. Two alternative ventilation systems are analyzed: a central system; and, a point-source system with small through-wall units distributed throughout the house. The report includes a design and cost analysis of these two approaches.« less

Building America Case Study: Columbia County Habitat for Humanity Passive Townhomes, Hudson, New York

DOE Office of Scientific and Technical Information (OSTI.GOV)

2016-04-01

Columbia County (New York) Habitat for Humanity built a pair of townhomes to Passive House criteria with the purpose of exploring approaches for achieving Passive House performance and to eventually develop a prototype design for future projects. The project utilized a 2x6 frame wall with a structural insulated panel curtain wall and a ventilated attic over a sealed OSB ceiling air barrier. Mechanical systems include a single head, wall mounted ductless mini-split heat pump in each unit and a heat recovery ventilator. Costs were $26,000 per unit higher for Passive House construction compared with the same home built to ENERGYmore » STAR version 3 specifications, representing about 18 percent of total construction cost. This report discusses the cost components, energy modeling results and lessons from construction. Two alternative ventilation systems are analyzed: a central system; and, a point-source system with small through-wall units distributed throughout the house. The report includes a design and cost analysis of these two approaches.« less

Transport characteristics of expiratory droplets and droplet nuclei in indoor environments with different ventilation airflow patterns.

PubMed

Wan, M P; Chao, C Y H

2007-06-01

Expiratory droplets and droplet nuclei can be pathogen carriers for airborne diseases. Their transport characteristics were studied in detail in two idealized floor-supply-type ventilation flow patterns: Unidirectional-upward and single-side-floor, using a multiphase numerical model. The model was validated by running interferometric Mie imaging experiments using test droplets with nonvolatile content, which formed droplet nuclei, ultimately, in a class-100 clean-room chamber. By comparing the droplet dispersion and removal characteristics with data of two other ceiling-supply ventilation systems collected from a previous work, deviations from the perfectly mixed ventilation condition were found to exist in various cases to different extent. The unidirectional-upward system was found to be more efficient in removing the smallest droplet nuclei (formed from 1.5 mum droplets) by air extraction, but it became less effective for larger droplets and droplet nuclei. Instead, the single-side-floor system was shown to be more favorable in removing these large droplets and droplet nuclei. In the single-side-floor system, the lateral overall dispersion coefficients for the small droplets and nuclei (initial size

Influence of face mask design on bag-valve-mask ventilation performance: a randomized simulation study.

PubMed

Na, J U; Han, S K; Choi, P C; Cho, J H; Shin, D H

2013-10-01

Different face mask designs can influence bag-valve-mask (BVM) ventilation performance during resuscitation. We compared a single-use, air-cushioned face mask (AM) with a reusable silicone face mask (SM) for quality of BVM ventilation on a manikin simulating cardiac arrest. Thirty-two physicians were recruited, and a prospective, randomized, crossover observational study was conducted after an American Heart Association-accredited basic life support provider course and standardized practice time were completed. Participants performed 12 cycles of BVM ventilation with both the AM and SM on a SmartMan lung simulator. Mean tidal volume was significantly higher in ventilations performed using the AM vs. the SM (548 ± 159 ml vs. 439 ± 163 ml, P < 0.01). In addition, the proportion of low-volume ventilation was significantly lower with the AM than the SM [6/12 (2-11) vs. 9/12 (5-12), P = 0.03]. Bag-valve-AM ventilation volume was not affected by the physical characteristics of the rescuers, except for sex. In contrast, bag-valve-SM ventilation volume was affected by most of the characteristics tested, including sex, height, weight, hand width, hand length, and grip power. The AM seems to be a more efficient face mask than the SM at delivering sufficient ventilation volumes. The performance of the AM did not seem to be associated with the physical characteristics of the rescuers, whereas that of the SM was affected by these factors. The SM may not be an appropriate face mask for performing one-person BVM ventilation during resuscitation for rescuers who are smaller in stature, have a smaller hand size, or have weaker grip power. © 2013 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Enhanced Photoacoustic Gas Analyser Response Time and Impact on Accuracy at Fast Ventilation Rates during Multiple Breath Washout

PubMed Central

Horsley, Alex; Macleod, Kenneth; Gupta, Ruchi; Goddard, Nick; Bell, Nicholas

2014-01-01

Background The Innocor device contains a highly sensitive photoacoustic gas analyser that has been used to perform multiple breath washout (MBW) measurements using very low concentrations of the tracer gas SF6. Use in smaller subjects has been restricted by the requirement for a gas analyser response time of <100 ms, in order to ensure accurate estimation of lung volumes at rapid ventilation rates. Methods A series of previously reported and novel enhancements were made to the gas analyser to produce a clinically practical system with a reduced response time. An enhanced lung model system, capable of delivering highly accurate ventilation rates and volumes, was used to assess in vitro accuracy of functional residual capacity (FRC) volume calculation and the effects of flow and gas signal alignment on this. Results 10–90% rise time was reduced from 154 to 88 ms. In an adult/child lung model, accuracy of volume calculation was −0.9 to 2.9% for all measurements, including those with ventilation rate of 30/min and FRC of 0.5 L; for the un-enhanced system, accuracy deteriorated at higher ventilation rates and smaller FRC. In a separate smaller lung model (ventilation rate 60/min, FRC 250 ml, tidal volume 100 ml), mean accuracy of FRC measurement for the enhanced system was minus 0.95% (range −3.8 to 2.0%). Error sensitivity to flow and gas signal alignment was increased by ventilation rate, smaller FRC and slower analyser response time. Conclusion The Innocor analyser can be enhanced to reliably generate highly accurate FRC measurements down at volumes as low as those simulating infant lung settings. Signal alignment is a critical factor. With these enhancements, the Innocor analyser exceeds key technical component recommendations for MBW apparatus. PMID:24892522

Testing, Modeling and System Impact of Metabolic Heat Regenerated Temperature Swing Adsorption

NASA Technical Reports Server (NTRS)

Lacomini, Christine S.; Powers, Aaron; Lewis, Matthew; Linrud, Christopher; Waguespack, Glenn; Conger, Bruce; Paul, Heather L.

2008-01-01

Metabolic heat regenerated temperature swing adsorption (MTSA) technology is being developed for removal and rejection of carbon dioxide (CO2) and heat from a portable life support system (PLSS) to the Martian environment. Previously, hardware was built and tested to demonstrate using heat from simulated, dry ventilation loop gas to affect the temperature swing required to regenerate an adsorbent used for CO2 removal. New testing has been performed using a moist, simulated ventilation loop gas to demonstrate the effects of water condensing and freezing in the heat exchanger during adsorbent regeneration. In addition, thermal models of the adsorbent during regeneration were modified and calibrated with test data to capture the effect of the CO2 heat of desorption. Finally, MTSA impact on PLSS design was evaluated by performing thermal balances assuming a specific PLSS architecture. Results using NASA s Extravehicular Activity System Sizing Analysis Tool (EVAS_SAT), a PLSS system evaluation tool, are presented.

Technology Solutions Case Study: Evaluation of Ventilation Strategies in New Construction Multifamily Buildings, New York, New York

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2014-09-01

In multifamily buildings, particularly in the Northeast, exhaust ventilation strategies are the norm as a means of meeting both local exhaust and whole-unit mechanical ventilation rates. The issue of where the "fresh" air is coming from is gaining significance as air-tightness standards for enclosures become more stringent, and the "normal leakage paths through the building envelope" disappear. Consortium for Advanced Residential Buildings researchers have found that the majority of high performance, new construction, multifamily housing in the Northeast use one of four general strategies for ventilation: continuous exhaust only with no designated supply or make-up air source, continuous exhaust withmore » ducted make-up air to apartments, continuous exhaust with supply through a make-up air device integral to the unit HVAC, and continuous exhaust with supply through a passive inlet device, such as a trickle vent. This research effort included several weeks of building pressure monitoring to validate system performance of the different strategies for providing make-up air to apartments.« less

Impact of surface disinfection and sterile draping of furniture on room air quality in a cardiac procedure room with a ventilation and air-conditioning system (extrusion airflow, cleanroom class 1b (DIN 1946-4))

PubMed Central

Below, Harald; Ryll, Sylvia; Empen, Klaus; Dornquast, Tina; Felix, Stefan; Rosenau, Heike; Kramer, Sebastian; Kramer, Axel

2010-01-01

In a cardiac procedure room, ventilated by a ventilation and air-conditioning system with turbulent mixed airflow, a protection zone in the operating area could be defined through visualization of airflows. Within this protection zone, no turbulence was detectable in the room air. Under the given conditions, disinfection of all surfaces including all furniture and equipment after the last operation and subsequent draping of furniture and all equipment that could not be removed from the room with sterile surgical drapes improved the indoor room air quality from cleanroom class C to cleanroom class B. This also allows procedures with elevated requirements to be performed in room class 1b. PMID:20941336

46 CFR 111.103-3 - Machinery space ventilation.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the supply...

46 CFR 111.103-3 - Machinery space ventilation.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the supply...

46 CFR 111.103-3 - Machinery space ventilation.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the supply...

46 CFR 111.103-3 - Machinery space ventilation.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the supply...

46 CFR 111.103-3 - Machinery space ventilation.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the supply...

Evaluation of ventilators for mouthpiece ventilation in neuromuscular disease.

PubMed

Khirani, Sonia; Ramirez, Adriana; Delord, Vincent; Leroux, Karl; Lofaso, Frédéric; Hautot, Solène; Toussaint, Michel; Orlikowski, David; Louis, Bruno; Fauroux, Brigitte

2014-09-01

Daytime mouthpiece ventilation is a useful adjunct to nocturnal noninvasive ventilation (NIV) in patients with neuromuscular disease. The aims of the study were to analyze the practice of mouthpiece ventilation and to evaluate the performance of ventilators for mouthpiece ventilation. Practice of mouthpiece ventilation was assessed by a questionnaire, and the performance of 6 home ventilators with mouthpiece ventilation was assessed in a bench test using 24 different conditions per ventilator: 3 mouthpieces, a child and an adult patient profile, and 4 ventilatory modes. Questionnaires were obtained from 30 subjects (mean age 33 ± 11 y) using NIV for 12 ± 7 y. Fifteen subjects used NIV for > 20 h/day, and 11 were totally ventilator-dependent. The subject-reported benefits of mouthpiece ventilation were a reduction in dyspnea (73%) and fatigue (93%) and an improvement in speech (43%) and eating (27%). The bench study showed that none of the ventilators, even those with mouthpiece ventilation software, were able to deliver mouthpiece ventilation without alarms and/or autotriggering in each condition. Alarms and/or ineffective triggering or autotriggering were observed in 135 of the 198 conditions. The occurrence of alarms was more common with a large mouthpiece without a filter compared to a small mouthpiece with a filter (P < .001), but it was not related to the patient profile, the ventilatory mode, or the type of ventilator. Subjects are satisfied with mouthpiece ventilation. Alarms are common with home ventilators, although less common in those with mouthpiece ventilation software. Improvements in home ventilators are needed to facilitate the expansion of mouthpiece ventilation. Copyright © 2014 by Daedalus Enterprises.

Cooperation of Horizontal Ground Heat Exchanger with the Ventilation Unit During Summer - Case Study

NASA Astrophysics Data System (ADS)

Romańska-Zapała, Anna; Furtak, Marcin; Dechnik, Mirosław

2017-10-01

Renewable energy sources are used in the modern energy-efficient buildings to improve their energy balance. One of them is used in the mechanical ventilation system ground air heat exchanger (earth-air heat exchanger - EAHX). This solution, right after heat recovery from exhaust air (recuperation), allows the reduction in the energy needed to obtain the desired temperature of supply air. The article presents the results of "in situ" measurements of pipe ground air heat exchanger cooperating with the air handling unit, supporting cooling the building in the summer season, in Polish climatic conditions. The laboratory consists of a ventilation unit intake - exhaust with rotor for which the source of fresh air is the air intake wall and two air intakes field cooperating with the tube with ground air heat exchangers. Selection of the source of fresh air is performed using sprocket with actuators. This system is part of the ventilation system of the Malopolska Laboratory of Energy-Efficient Building (MLBE) building of Cracow University of Technology. The measuring system are, among others, the sensors of parameters of air inlets and outlets of the heat exchanger channels EAHX and weather station that senses the local weather conditions. The measurement data are recorded and archived by the integrated process control system in the building of MLBE. During the study measurements of operating parameters of the ventilation unit cooperating with the selected source of fresh air were performed. Two cases of operation of the system: using EAHX heat exchanger and without it, were analyzed. Potentially the use of ground air heat exchanger in the mechanical ventilation system can reduce the energy demand for heating or cooling rooms by the pre-adjustment of the supply air temperature. Considering the results can be concluded that the continuous use of these exchangers is not optimal. This relationship is appropriate not only on an annual basis for the transitional periods (spring and autumn), but also in individual days in the potentially most favorable periods of work exchanger (summer and winter). Inappropriate operation of the heat exchanger, will lead to a temporary increase in energy consumption for the preparation of the desired air temperature, relative to the fresh air unit which is non-pretreated. For optimal energy system operation: exchanger EAHX - air handling unit, to preserve the most favourable parameters of inlet air to handling unit, there is a need to dynamically adjust the source of fresh air, depending on changing external conditions and the required outlet temperature of central unit (temperature of air forced to the rooms).

New Whole-House Solutions Case Study: Testing Ductless Heat Pumps in High-Performance Affordable Housing, the Woods at Golden Given - Tacoma, Washington

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2015-06-01

The Woods is a 30-home, high- performance, energy efficient sustainable community built by Habitat for Humanity (HFH). With Support from Tacoma Public Utilities, Washington State University (part of the Building America Partnership for Improved Residential Construction) is researching the energy performance of these homes and the ductless heat pumps (DHP) they employ. This project provides Building America with an opportunity to: field test HVAC equipment, ventilation system air flows, building envelope tightness, lighting, appliance, and other input data that are required for preliminary Building Energy Optimization (BEopt™) modeling and ENERGY STAR® field verification; analyze cost data from HFH and othermore » sources related to building-efficiency measures that focus on the DHP/hybrid heating system and heat recovery ventilation system; evaluate the thermal performance and cost benefit of DHP/hybrid heating systems in these homes from the perspective of homeowners; compare the space heating energy consumption of a DHP/electric resistance (ER) hybrid heating system to that of a traditional zonal ER heating system; conduct weekly "flip-flop tests" to compare space heating, temperature, and relative humidity in ER zonal heating mode to DHP/ER mode.« less

Multifaceted bench comparative evaluation of latest intensive care unit ventilators.

PubMed

Garnier, M; Quesnel, C; Fulgencio, J-P; Degrain, M; Carteaux, G; Bonnet, F; Similowski, T; Demoule, A

2015-07-01

Independent bench studies using specific ventilation scenarios allow testing of the performance of ventilators in conditions similar to clinical settings. The aims of this study were to determine the accuracy of the latest generation ventilators to deliver chosen parameters in various typical conditions and to provide clinicians with a comprehensive report on their performance. Thirteen modern intensive care unit ventilators were evaluated on the ASL5000 test lung with and without leakage for: (i) accuracy to deliver exact tidal volume (VT) and PEEP in assist-control ventilation (ACV); (ii) performance of trigger and pressurization in pressure support ventilation (PSV); and (iii) quality of non-invasive ventilation algorithms. In ACV, only six ventilators delivered an accurate VT and nine an accurate PEEP. Eleven devices failed to compensate VT and four the PEEP in leakage conditions. Inspiratory delays differed significantly among ventilators in invasive PSV (range 75-149 ms, P=0.03) and non-invasive PSV (range 78-165 ms, P<0.001). The percentage of the ideal curve (concomitantly evaluating the pressurization speed and the levels of pressure reached) also differed significantly (range 57-86% for invasive PSV, P=0.04; and 60-90% for non-invasive PSV, P<0.001). Non-invasive ventilation algorithms efficiently prevented the decrease in pressurization capacities and PEEP levels induced by leaks in, respectively, 10 and 12 out of the 13 ventilators. We observed real heterogeneity of performance amongst the latest generation of intensive care unit ventilators. Although non-invasive ventilation algorithms appear to maintain adequate pressurization efficiently in the case of leakage, basic functions, such as delivered VT in ACV and pressurization in PSV, are often less reliable than the values displayed by the device suggest. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A bench study of intensive-care-unit ventilators: new versus old and turbine-based versus compressed gas-based ventilators

PubMed Central

Thille, Arnaud W.; Lyazidi, Aissam; Richard, Jean-Christophe M.; Galia, Fabrice; Brochard, Laurent

2009-01-01

Objective To compare 13 commercially available, new-generation, intensive-care-unit (ICU) ventilators regarding trigger function, pressurization capacity during pressure-support ventilation (PSV), accuracy of pressure measurements and expiratory resistance. Design and Setting Bench study at a research laboratory in a university hospital. Material Four turbine-based ventilators and nine conventional servo-valve compressed-gas ventilators were tested using a two-compartment lung model. Results Three levels of effort were simulated. Each ventilator was evaluated at four PSV levels (5, 10, 15, and 20 cm H2O), with and without positive end-expiratory pressure (5 cm H2O, Trigger function was assessed as the time from effort onset to detectable pressurization. Pressurization capacity was evaluated using the airway pressure-time product computed as the net area under the pressure-time curve over the first 0.3 s after inspiratory effort onset. Expiratory resistance was evaluated by measuring trapped volume in controlled ventilation. Significant differences were found across the ventilators, with a range of triggering-delay from 42 ms to 88 ms for all conditions averaged (P<.001). Under difficult conditions, the triggering delay was longer than 100 ms and the pressurization was poor with five ventilators at PSV5 and three at PSV10, suggesting an inability to unload patient’s effort. On average, turbine-based ventilators performed better than conventional ventilators, which showed no improvement compared to a 2000 bench comparison. Conclusion Technical performances of trigger function, pressurization capacity and expiratory resistance vary considerably across new-generation ICU ventilators. ICU ventilators seem to have reached a technical ceiling in recent years, and some ventilators still perform inadequately. PMID:19352622

A bench study of intensive-care-unit ventilators: new versus old and turbine-based versus compressed gas-based ventilators.

PubMed

Thille, Arnaud W; Lyazidi, Aissam; Richard, Jean-Christophe M; Galia, Fabrice; Brochard, Laurent

2009-08-01

To compare 13 commercially available, new-generation, intensive-care-unit (ICU) ventilators in terms of trigger function, pressurization capacity during pressure-support ventilation (PSV), accuracy of pressure measurements, and expiratory resistance. Bench study at a research laboratory in a university hospital. Four turbine-based ventilators and nine conventional servo-valve compressed-gas ventilators were tested using a two-compartment lung model. Three levels of effort were simulated. Each ventilator was evaluated at four PSV levels (5, 10, 15, and 20 cm H2O), with and without positive end-expiratory pressure (5 cm H2O). Trigger function was assessed as the time from effort onset to detectable pressurization. Pressurization capacity was evaluated using the airway pressure-time product computed as the net area under the pressure-time curve over the first 0.3 s after inspiratory effort onset. Expiratory resistance was evaluated by measuring trapped volume in controlled ventilation. Significant differences were found across the ventilators, with a range of triggering delays from 42 to 88 ms for all conditions averaged (P < 0.001). Under difficult conditions, the triggering delay was longer than 100 ms and the pressurization was poor for five ventilators at PSV5 and three at PSV10, suggesting an inability to unload patient's effort. On average, turbine-based ventilators performed better than conventional ventilators, which showed no improvement compared to a bench comparison in 2000. Technical performance of trigger function, pressurization capacity, and expiratory resistance differs considerably across new-generation ICU ventilators. ICU ventilators seem to have reached a technical ceiling in recent years, and some ventilators still perform inadequately.

[Basic life support in pediatrics].

PubMed

Calvo Macías, A; Manrique Martínez, I; Rodríguez Núñez, A; López-Herce Cid, J

2006-09-01

Basic life support (BLS) is the combination of maneuvers that identifies the child in cardiopulmonary arrest and initiates the substitution of respiratory and circulatory function, without the use of technical adjuncts, until the child can receive more advanced treatment. BLS includes a sequence of steps or maneuvers that should be performed sequentially: ensuring the safety of rescuer and child, assessing unconsciousness, calling for help, positioning the victim, opening the airway, assessing breathing, ventilating, assessing signs of circulation and/or central arterial pulse, performing chest compressions, activating the emergency medical service system, and checking the results of resuscitation. The most important changes in the new guidelines are the compression: ventilation ratio and the algorithm for relieving foreign body airway obstruction. A compression/ ventilation ratio of 30:2 will be recommended for lay rescuers of infants, children and adults. Health professionals will use a compression: ventilation ratio of 15:2 for infants and children. If the health professional is alone, he/she may also use a ratio of 30:2 to avoid fatigue. In the algorithm for relieving foreign body airway obstruction, when the child becomes unconscious, the maneuvers will be similar to the BLS sequence with chest compressions (functioning as a deobstruction procedure) and ventilation, with reassessment of the mouth every 2 min to check for a foreign body, and evaluation of breathing and the presence of vital signs. BLS maneuvers are easy to learn and can be performed by anyone with adequate training. Therefore, BLS should be taught to all citizens.

Requirements and Sizing Investigation for Constellation Space Suit Portable Life Support System Trace Contaminant Control

NASA Technical Reports Server (NTRS)

Paul, Heather L.; Jennings, Mallory A.; Waguespack, Glenn

2010-01-01

The Trace Contaminant Control System (TCCS), located within the ventilation loop of the Constellation Space Suit Portable Life Support System (PLSS), is responsible for removing hazardous trace contaminants from the space suit ventilation flow. This paper summarizes the results of a trade study that evaluated if trace contaminant control could be accomplished without a TCCS, relying on suit leakage, ullage loss from the carbon dioxide and humidity control system, and other factors. Trace contaminant generation rates were revisited to verify that values reflect the latest designs for Constellation Space Suit System (CSSS) pressure garment materials and PLSS hardware. Additionally, TCCS sizing calculations were performed and a literature survey was conducted to review the latest developments in trace contaminant technologies.

Steady-state balance model to calculate the indoor climate of livestock buildings, demonstrated for finishing pigs

NASA Astrophysics Data System (ADS)

Schauberger, G.; Piringer, M.; Petz, E.

The indoor climate of livestock buildings is of importance for the well-being and health of animals and their production performance (daily weight gain, milk yield etc). By using a steady-state model for the sensible and latent heat fluxes and the CO2 and odour mass flows, the indoor climate of mechanically ventilated livestock buildings can be calculated. These equations depend on the livestock (number of animals and how they are kept), the insulation of the building and the characteristics of the ventilation system (ventilation rate). Since the model can only be applied to animal houses where the ventilation systems are mechanically controlled (this is the case for a majority of finishing pig units), the calculations were done for an example of a finishing pig unit with 1000 animal places. The model presented used 30 min values of the outdoor parameters temperature and humidity, collected over a 2-year period, as input. The projected environment inside the livestock building was compared with recommended values. The duration of condensation on the inside surfaces was also calculated.

Flow analysis of airborne particles in a hospital operating room

NASA Astrophysics Data System (ADS)

Faeghi, Shiva; Lennerts, Kunibert

2016-06-01

Preventing airborne infections during a surgery has been always an important issue to deliver effective and high quality medical care to the patient. One of the important sources of infection is particles that are distributed through airborne routes. Factors influencing infection rates caused by airborne particles, among others, are efficient ventilation and the arrangement of surgical facilities inside the operating room. The paper studies the ventilation airflow pattern in an operating room in a hospital located in Tehran, Iran, and seeks to find the efficient configurations with respect to the ventilation system and layout of facilities. This study uses computational fluid dynamics (CFD) and investigates the effects of different inflow velocities for inlets, two pressurization scenarios (equal and excess pressure) and two arrangements of surgical facilities in room while the door is completely open. The results show that system does not perform adequately when the door is open in the operating room under the current conditions, and excess pressure adjustments should be employed to achieve efficient results. The findings of this research can be discussed in the context of design and controlling of the ventilation facilities of operating rooms.

Performance of Portable Ventilators at Altitude

DTIC Science & Technology

2015-03-30

collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT...Deploying ventilators that can maintain a consistent tidal volume (VT) delivery at various altitudes is imperative for lung protection when...performance of mechanical ventilators calibrated for operation at sea level. Deploying ventilators that can maintain a consistent tidal volume (VT) delivery

VENTILATION TECHNOLOGY SYSTEMS ANALYSIS

EPA Science Inventory

The report gives results of a project to develop a systems analysis of ventilation technology and provide a state-of-the-art assessment of ventilation and indoor air quality (IAQ) research needs. (NOTE: Ventilation technology is defined as the hardware necessary to bring outdoor ...

Change Is In the Air: What You Need to Know About Pharmacy Ventilation Under United States Pharmacopeia <800>.

PubMed

Laniewicz, Cheryl

2017-01-01

On July 1, 2018, United States Pharmacopeia <800> takes effect in those states that adopt it, and the discussion within this article may be applicable to those states that develop their own standards. United States Pharmacopeia <800> changes requirements for storage and compounding of hazardous drugs. The new requirements have important implications for air management and ventilation in some pharmacies. This article discusses how United States Pharmacopeia <800> compares to United States Pharmacopeia <797>, how the changes impact room ventilation and pressurization requirements, and how high-performance airflow control systems that ensure compliance and safety are impacted. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

A regulator for pressure-controlled total-liquid ventilation.

PubMed

Robert, Raymond; Micheau, Philippe; Avoine, Olivier; Beaudry, Benoit; Beaulieu, Alexandre; Walti, Hervé

2010-09-01

Total-liquid ventilation (TLV) is an innovative experimental method of mechanical-assisted ventilation in which lungs are totally filled and then ventilated with a tidal volume of perfluorochemical liquid by using a dedicated liquid ventilator. Such a novel medical device must resemble other conventional ventilators: it must be able to conduct controlled-pressure ventilation. The objective was to design a robust controller to perform pressure-regulated expiratory flow and to implement it on our latest liquid-ventilator prototype (Inolivent-4). Numerical simulations, in vitro experiments, and in vivo experiments in five healthy term newborn lambs have demonstrated that it was efficient to generate expiratory flows while avoiding collapses. Moreover, the in vivo results have demonstrated that our liquid ventilator can maintain adequate gas exchange, normal acid-base equilibrium, and achieve greater minute ventilation, better oxygenation and CO2 extraction, while nearing flow limits. Hence, it is our suggestion to perform pressure-controlled ventilation during expiration with minute ventilation equal or superior to 140 mL x min(-1) x kg(-1) in order to ensure PaCO2 below 55 mmHg. From a clinician's point of view, pressure-controlled ventilation greatly simplifies the use of the liquid ventilator, which will certainly facilitate its introduction in intensive care units for clinical applications.

Classroom ventilation and indoor air quality-results from the FRESH intervention study.

PubMed

Rosbach, J; Krop, E; Vonk, M; van Ginkel, J; Meliefste, C; de Wind, S; Gehring, U; Brunekreef, B

2016-08-01

Inadequate ventilation of classrooms may lead to increased concentrations of pollutants generated indoors in schools. The FRESH study, on the effects of increased classroom ventilation on indoor air quality, was performed in 18 naturally ventilated classrooms of 17 primary schools in the Netherlands during the heating seasons of 2010-2012. In 12 classrooms, ventilation was increased to targeted CO2 concentrations of 800 or 1200 ppm, using a temporary CO2 controlled mechanical ventilation system. Six classrooms were included as controls. In each classroom, data on endotoxin, β(1,3)-glucans, and particles with diameters of <10 μm (PM10 ) and <2.5 μm (PM2.5 ) and nitrogen dioxide (NO2 ) were collected during three consecutive weeks. Associations between the intervention and these measured indoor air pollution levels were assessed using mixed models, with random classroom effects. The intervention lowered endotoxin and β(1,3)-glucan levels and PM10 concentrations significantly. PM10 for instance was reduced by 25 μg/m³ (95% confidence interval 13-38 μg/m³) from 54 μg/m³ at maximum ventilation rate. No significant differences were found between the two ventilation settings. Concentrations of PM2.5 and NO2 were not affected by the intervention. Our results provide evidence that increasing classroom ventilation is effective in decreasing the concentrations of some indoor-generated pollutants. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Building America Case Study: Sealed Crawl Spaces with Integrated Whole-House Ventilation in a Cold Climate, Ithaca, New York

DOE Office of Scientific and Technical Information (OSTI.GOV)

"9One method of code-compliance for crawlspaces is to seal and insulate the crawlspace, rather than venting to the outdoors. However, codes require mechanical ventilation; either via conditioned supply air from the HVAC system, or a continuous exhaust ventilation strategy. As the CARB's building partner, Ithaca Neighborhood Housing Services, intended to use the unvented crawlspace in a recent development, CARB was interested in investigating a hybrid ventilation method that includes the exhaust air from the crawlspace as a portion of an ASHRAE 62.2 compliant whole-house ventilation strategy. This hybrid ventilation method was evaluated through a series of long-term monitoring tests thatmore » observed temperature, humidity, and pressure conditions through the home and crawlspace. Additionally, CARB worked with NREL to perform multi-point tracer gas testing on six separate ventilation strategies - varying portions of 62.2 required flow supplied by the crawlspace fan and an upstairs bathroom fan. The intent of the tracer gas testing was to identify effective Reciprocal Age of Air (RAoA), which is equivalent to the air change rate in well-mixed zones, for each strategy while characterizing localized infiltration rates in several areas of the home.« less

Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house.

PubMed

Singer, B C; Delp, W W; Black, D R; Walker, I S

2017-07-01

This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250 m downwind of the I-80 freeway in Sacramento, California. Systems were evaluated for reducing indoor concentrations of outdoor particles in summer and fall/winter, ozone in summer, and particles from stir-fry cooking. Air exchange rate was measured continuously. Energy use was estimated for year-round operation in California. Exhaust ventilation without enhanced filtration provided indoor PM 2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection, whereas supply MERV16 filtration reduced PM 2.5 by 97-98% relative to outdoors. Supply filtration systems used little energy but provided no benefits for indoor-generated particles. Systems with MERV13-16 filter in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM 2.5 by 93-98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM 2.5 . Indoor ozone was 3-4% of outdoors for all systems except an electronic air cleaner that produced ozone. Filtration via the FAU or portable filtration units lowered PM 2.5 by 25-75% when operated over the hour following cooking. The energy for year-round operation of FAU filtration with an efficient blower motor was estimated at 600 kWh/year. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singer, Brett C.; Delp, William W.; Black, Douglas R.

This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250m downwind of the I-80 freeway in Sacramento, California. Systems were evaluated for reducing indoor concentrations of outdoor particles in summer and fall/winter, ozone in summer, and particles from stir-fry cooking. Air exchange rate was measured continuously. Energy use was estimated for year-round operation in California. Exhaust ventilation without enhanced filtration produced indoor PM 2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection whereas supply MERV16 filtration reduced PM 2.55 by 97-98% relative to outdoors. Supply filtration systems usedmore » little energy but provided no benefits for indoor-generated particles. Systems with MERV13-16 filters in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM 2.5 by 93-98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM 2.5. Indoor ozone was 3-4% of outdoors for all systems except an electronic air cleaner that produced ozone. Filtration via the FAU or portable filtration units lowered PM 2.5 by 25-75% when operated over the hour following cooking. The energy for year-round operation of FAU filtration with an efficient blower motor was estimated at 600 kWh/year.« less

Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singer, B. C.; Delp, W. W.; Black, D. R.

This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250 m downwind of the I-80 freeway in Sacramento, California. Systems were evaluated for reducing indoor concentrations of outdoor particles in summer and fall/winter, ozone in summer, and particles from stir-fry cooking. Air exchange rate was measured continuously. Energy use was estimated for year-round operation in California. Exhaust ventilation without enhanced filtration provided indoor PM 2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection, whereas supply MERV16 filtration reduced PM 2.5 by 97-98% relative to outdoors. Supply filtration systems usedmore » little energy but provided no benefits for indoor-generated particles. Systems with MERV13-16 fil ter in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM 2.5 by 93-98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM 2.5 . Indoor ozone was 3-4% of outdoors for all systems except an electronic air cleaner that produced ozone. Filtration via the FAU or portable filtration units lowered PM 2.5 by 25-75% when operated over the hour following cooking. The energy for year-round operation of FAU filtration with an efficient blower motor was estimated at 600 kWh/year.« less

Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house

DOE PAGES

Singer, B. C.; Delp, W. W.; Black, D. R.; ...

2016-12-05

This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250 m downwind of the I-80 freeway in Sacramento, California. Systems were evaluated for reducing indoor concentrations of outdoor particles in summer and fall/winter, ozone in summer, and particles from stir-fry cooking. Air exchange rate was measured continuously. Energy use was estimated for year-round operation in California. Exhaust ventilation without enhanced filtration provided indoor PM 2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection, whereas supply MERV16 filtration reduced PM 2.5 by 97-98% relative to outdoors. Supply filtration systems usedmore » little energy but provided no benefits for indoor-generated particles. Systems with MERV13-16 fil ter in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM 2.5 by 93-98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM 2.5 . Indoor ozone was 3-4% of outdoors for all systems except an electronic air cleaner that produced ozone. Filtration via the FAU or portable filtration units lowered PM 2.5 by 25-75% when operated over the hour following cooking. The energy for year-round operation of FAU filtration with an efficient blower motor was estimated at 600 kWh/year.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fisk, William J.; Destaillats, H.; Apte, M.G.

Heating, ventilating, and cooling classrooms in California consume substantial electrical energy. Indoor air quality (IAQ) in classrooms affects studenthealth and performance. In addition to airborne pollutants that are emitted directly by indoor sources and those generated outdoors, secondary pollutants can be formed indoors by chemical reaction of ozone with other chemicals and materials. Filters are used in nearly all classroom heating, ventilation and air?conditioning (HVAC) systems to maintain energy-efficient HVAC performance and improve indoor air quality; however, recent evidence indicates that ozone reactions with filters may, in fact, be a source of secondary pollutants. This project quantitatively evaluated ozone depositionmore » in HVAC filters and byproduct formation, and provided a preliminary assessment of the extent towhich filter systems are degrading indoor air quality. The preliminary information obtained will contribute to the design of subsequent research efforts and the identification of energy efficient solutions that improve indoor air quality in classrooms and the health and performance of students.« less

Kuipers uses vacuum cleaner while performing maintenance in the Columbus Module

NASA Image and Video Library

2012-02-22

ISS030-E-093398 (22 Feb. 2012) --- European Space Agency astronaut Andre Kuipers, Expedition 30 flight engineer, uses a vacuum cleaner while performing the scheduled extensive cleanup of ventilation systems in the Columbus laboratory of the International Space Station.

Effects of types of ventilation system on indoor particle concentrations in residential buildings.

PubMed

Park, J S; Jee, N-Y; Jeong, J-W

2014-12-01

The objective of this study was to quantify the influence of ventilation systems on indoor particle concentrations in residential buildings. Fifteen occupied, single-family apartments were selected from three sites. The three sites have three different ventilation systems: unbalanced mechanical ventilation, balanced mechanical ventilation, and natural ventilation. Field measurements were conducted between April and June 2012, when outdoor air temperatures were comfortable. Number concentrations of particles, PM2.5 and CO2 , were continuously measured both outdoors and indoors. In the apartments with natural ventilation, I/O ratios of particle number concentrations ranged from 0.56 to 0.72 for submicron particles, and from 0.25 to 0.60 for particles larger than 1.0 μm. The daily average indoor particle concentration decreased to 50% below the outdoor level for submicron particles and 25% below the outdoor level for fine particles, when the apartments were mechanically ventilated. The two mechanical ventilation systems reduced the I/O ratios by 26% for submicron particles and 65% for fine particles compared with the natural ventilation. These results showed that mechanical ventilation can reduce exposure to outdoor particles in residential buildings. Results of this study confirm that mechanical ventilation with filtration can significantly reduce indoor particle levels compared with natural ventilation. The I/O ratios of particles substantially varied at the naturally ventilated apartments because of the influence of variable window opening conditions and unsteadiness of wind flow on the penetration of outdoor air particles. For better prediction of the exposure to outdoor particles in naturally ventilated residential buildings, it is important to understand the penetration of outdoor particles with variable window opening conditions. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Development Specification for the FN-323/324, Oxygen Ventilation Loop Fan Assembly

NASA Technical Reports Server (NTRS)

Ralston, Russell; Campbell, Colin

2017-01-01

This specification establishes the requirements for design, performance, safety, and manufacture of the FN-323/324, Oxygen Ventilation Loop Fan Assembly as part of the Advanced EMU (AEMU) Portable Life Support System (PLSS). Fan development for the advanced Portable Life Support System (PLSS) began in 2009 with the development of Fan 1.0. This fan was used in PLSS 2.0 for circulation of the ventilation loop gas. Fan 2.0 was delivered in 2015 and will be used in the PLSS 2.5 Live Loads test series. This fan used the same motor as Fan 1.0, but had a larger volute and impeller in hopes of achieving lower speeds. The next iteration of the advanced PLSS fan is the subject of the requirements contained within this document, and will be used with the PLSS 2.5 -302 configuration.

Energy-Efficient Management of Mechanical Ventilation and Relative Humidity in Hot-Humid Climates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Withers, Jr., Charles R.

2016-12-01

In hot and humid climates, it is challenging to energy-efficiently maintain indoor RH at acceptable levels while simultaneously providing required ventilation, particularly in high performance low cooling load homes. The fundamental problem with solely relying on fixed capacity central cooling systems to manage moisture during low sensible load periods is that they are oversized for cooler periods of the year despite being 'properly sized' for a very hot design cooling day. The primary goals of this project were to determine the impact of supplementing a central space conditioning system with 1) a supplemental dehumidifier and 2) a ductless mini-split onmore » seasonal energy use and summer peak power use as well as the impact on thermal distribution and humidity control inside a completely furnished lab home that was continuously ventilated in accordance with ASHRAE 62.2-2013.« less

Building America Case Study: Energy Efficient Management of Mechanical Ventilation and Relative Humidity in Hot-Humid Climates, Cocoa, Florida

DOE Office of Scientific and Technical Information (OSTI.GOV)

2017-01-01

In hot and humid climates, it is challenging to energy-efficiently maintain indoor RH at acceptable levels while simultaneously providing required ventilation, particularly in high performance low cooling load homes. The fundamental problem with solely relying on fixed capacity central cooling systems to manage moisture during low sensible load periods is that they are oversized for cooler periods of the year despite being 'properly sized' for a very hot design cooling day. The primary goals of this project were to determine the impact of supplementing a central space conditioning system with 1) a supplemental dehumidifier and 2) a ductless mini-split onmore » seasonal energy use and summer peak power use as well as the impact on thermal distribution and humidity control inside a completely furnished lab home that was continuously ventilated in accordance with ASHRAE 62.2-2013.« less

Development of a Fan for Future Space Suit Applications

NASA Technical Reports Server (NTRS)

Paul. Heather L.; Converse, David; Dionne, Steven; Moser, Jeff

2010-01-01

NASA's next generation space suit system will place new demands on the fan used to circulate breathing gas through the ventilation loop of the portable life support system. Long duration missions with frequent extravehicular activities (EVAs), the requirement for significant increases in reliability and durability, and a mission profile that imposes strict limits on weight, volume and power create the basis for a set of requirements that demand more performance than is available from existing fan designs. This paper describes the development of a new fan to meet these needs. A centrifugal fan was designed with a normal operating speed of approximately 39,400 rpm to meet the ventilation flow requirements while also meeting the aggressive minimal packaging, weight and power requirements. The prototype fan also operates at 56,000 rpm to satisfy a second operating condition associated with a single fan providing ventilation flow to two spacesuits connected in series. This fan incorporates a novel nonmetallic "can" to keep the oxygen flow separate from the motor electronics, thus eliminating ignition potential. The nonmetallic can enables a small package size and low power consumption. To keep cost and schedule within project bounds a commercial motor controller was used. The fan design has been detailed and implemented using materials and approaches selected to address anticipated mission needs. Test data is presented to show how this fan performs relative to anticipated ventilation requirements for the EVA portable life support system. Additionally, data is presented to show tolerance to anticipated environmental factors such as acoustics, shock, and vibration. Recommendations for forward work to progress the technology readiness level and prepare the fan for the next EVA space suit system are also discussed.

The effects of exogenous surfactant administration on ventilation-induced inflammation in mouse models of lung injury.

PubMed

Puntorieri, Valeria; Hiansen, Josh Qua; McCaig, Lynda A; Yao, Li-Juan; Veldhuizen, Ruud A W; Lewis, James F

2013-11-20

Mechanical ventilation (MV) is an essential supportive therapy for acute lung injury (ALI); however it can also contribute to systemic inflammation. Since pulmonary surfactant has anti-inflammatory properties, the aim of the study was to investigate the effect of exogenous surfactant administration on ventilation-induced systemic inflammation. Mice were randomized to receive an intra-tracheal instillation of a natural exogenous surfactant preparation (bLES, 50 mg/kg) or no treatment as a control. MV was then performed using the isolated and perfused mouse lung (IPML) set up. This model allowed for lung perfusion during MV. In experiment 1, mice were exposed to mechanical ventilation only (tidal volume =20 mL/kg, 2 hours). In experiment 2, hydrochloric acid or air was instilled intra-tracheally four hours before applying exogenous surfactant and ventilation (tidal volume =5 mL/kg, 2 hours). For both experiments, exogenous surfactant administration led to increased total and functional surfactant in the treated groups compared to the controls. Exogenous surfactant administration in mice exposed to MV only did not affect peak inspiratory pressure (PIP), lung IL-6 levels and the development of perfusate inflammation compared to non-treated controls. Acid injured mice exposed to conventional MV showed elevated PIP, lung IL-6 and protein levels and greater perfusate inflammation compared to air instilled controls. Instillation of exogenous surfactant did not influence the development of lung injury. Moreover, exogenous surfactant was not effective in reducing the concentration of inflammatory cytokines in the perfusate. The data indicates that exogenous surfactant did not mitigate ventilation-induced systemic inflammation in our models. Future studies will focus on altering surfactant composition to improve its immuno-modulating activity.

Software Configuration Management Plan for the B-Plant Canyon Ventilation Control System

DOE Office of Scientific and Technical Information (OSTI.GOV)

MCDANIEL, K.S.

1999-08-31

Project W-059 installed a new B Plant Canyon Ventilation System. Monitoring and control of the system is implemented by the Canyon Ventilation Control System (CVCS). This Software Configuration Management Plan provides instructions for change control of the CVCS.

Anaesthesia ventilators.

PubMed

Jain, Rajnish K; Swaminathan, Srinivasan

2013-09-01

Anaesthesia ventilators are an integral part of all modern anaesthesia workstations. Automatic ventilators in the operating rooms, which were very simple with few modes of ventilation when introduced, have become very sophisticated with many advanced ventilation modes. Several systems of classification of anaesthesia ventilators exist based upon various parameters. Modern anaesthesia ventilators have either a double circuit, bellow design or a single circuit piston configuration. In the bellows ventilators, ascending bellows design is safer than descending bellows. Piston ventilators have the advantage of delivering accurate tidal volume. They work with electricity as their driving force and do not require a driving gas. To enable improved patient safety, several modifications were done in circle system with the different types of anaesthesia ventilators. Fresh gas decoupling is a modification done in piston ventilators and in descending bellows ventilator to reduce th incidence of ventilator induced volutrauma. In addition to the conventional volume control mode, modern anaesthesia ventilators also provide newer modes of ventilation such as synchronised intermittent mandatory ventilation, pressure-control ventilation and pressure-support ventilation (PSV). PSV mode is particularly useful for patients maintained on spontaneous respiration with laryngeal mask airway. Along with the innumerable benefits provided by these machines, there are various inherent hazards associated with the use of the ventilators in the operating room. To use these workstations safely, it is important for every Anaesthesiologist to have a basic understanding of the mechanics of these ventilators and breathing circuits.

The performances of standard and ResMed masks during bag-valve-mask ventilation.

PubMed

Lee, Hyoung Youn; Jeung, Kyung Woon; Lee, Byung Kook; Lee, Seung Joon; Jung, Yong Hun; Lee, Geo Sung; Min, Yong Il; Heo, Tag

2013-01-01

A tight mask seal is frequently difficult to obtain and maintain during single-rescuer bag-valve-mask (BVM) ventilation. The ResMed mask (Bella Vista, NSW, Australia) is a continuous-positive-airway-pressure mask (CM) designed for noninvasive ventilation. In this study, we compared the ventilation performances of a standard mask (SM) and a ResMed CM using a simulation manikin in an out-of-hospital single-rescuer BVM ventilation scenario. Thirty emergency medical technicians (EMTs) performed two 2-minute attempts to ventilate a simulation manikin using BVM ventilation, alternatively, with the SM or the ResMed CM in a randomized order. Ventilation parameters including tidal volume and peak airway pressure were measured using computer analysis software connected to the simulation manikin. Successful volume delivery was defined as delivery of 440-540 mL of tidal volume in accord with present cardiopulmonary resuscitation guidelines. BVM ventilation using the ResMed CM produced higher mean (± standard deviation) tidal volumes (452 ± 50 mL vs. 394 ± 113 mL, p = 0.014) and had a higher proportion of successful volume deliveries (65.3% vs. 26.7%, p < 0.001) than that using the SM. Peak airway pressure was higher in BVM ventilation using the ResMed CM (p = 0.035). Stomach insufflation did not occur during either method. Twenty-nine of the participants (96.7%) preferred BVM ventilation using the ResMed CM. BVM ventilations using ResMed CM resulted in a significantly higher proportion of successful volume deliveries meeting the currently recommended range of tidal volume. Clinical studies are needed to determine the value of the ResMed CM for BVM ventilation.

3D printing technology speeds development.

PubMed

McGowan, James

2013-10-01

James McGowan, R&D product designer for Monodraught, a specialist in 'natural ventilation, natural daylight, and natural cooling systems', discusses the development of Cool-phase, the company's latest innovative application of phase change material (PCM) as a thermal energy store used to actively ventilate and cool buildings. As he explains, when the company decided to re-design an already successful product to further enhance its performance, the use of 3D modelling greatly speeded up prototyping, and helped the design process progress considerably more quickly.

46 CFR 111.106-15 - Ventilation of hazardous locations.

Code of Federal Regulations, 2014 CFR

2014-10-01

... its operational controls outside the ventilated space, if the system is mechanical; and (3) Have a... opening. (c) The mechanical ventilation of enclosed flammable or combustible liquid cargo handling or.... The power ventilation system must be designed to remove vapors from the bottom of the space at points...

Head elevation and lateral head rotation effect on facemask ventilation efficiency: Randomized crossover trials.

PubMed

Matsunami, Sayuri; Komasawa, Nobuyasu; Konishi, Yuki; Minami, Toshiaki

2017-11-01

We performed two prospective randomized crossover trials to evaluate the effect of head elevation or lateral head rotation to facemask ventilation volume. In the first trial, facemask ventilation was performed with a 12-cm high pillow (HP) and 4-cm low pillow (LP) in 20 female patients who were scheduled to undergo general anesthesia. In the second trial, facemask ventilation was performed with and without lateral head rotation in another 20 female patients. Ventilation volume was measured in a pressure-controlled ventilation (PCV) manner at 10, 15, and 20 cmH 2 O inspiratory pressures. In the first trial evaluating head elevation effect, facemask ventilation volume was significantly higher with a HP than with a LP at 15 and 20 cmH 2 O inspiratory pressure (15 cmH 2 O: HP median 540 [ IQR 480-605] mL, LP 460 [400-520] mL, P=0.006, 20 cmH 2 O: HP 705 [650-800] mL, LP 560 [520-677] mL, P<0.001). In the second trial, lateral head rotation did not significantly increase facemask ventilation volume at all inspiratory pressure. Head elevation increased facemask ventilation volume in normal airway patients, while lateral head rotation did not. Copyright © 2017 Elsevier Inc. All rights reserved.

Computer-Aided Classification of Visual Ventilation Patterns in Patients with Chronic Obstructive Pulmonary Disease at Two-Phase Xenon-Enhanced CT

PubMed Central

Yoon, Soon Ho; Jung, Julip; Hong, Helen; Park, Eun Ah; Lee, Chang Hyun; Lee, Youkyung; Jin, Kwang Nam; Choo, Ji Yung; Lee, Nyoung Keun

2014-01-01

Objective To evaluate the technical feasibility, performance, and interobserver agreement of a computer-aided classification (CAC) system for regional ventilation at two-phase xenon-enhanced CT in patients with chronic obstructive pulmonary disease (COPD). Materials and Methods Thirty-eight patients with COPD underwent two-phase xenon ventilation CT with resulting wash-in (WI) and wash-out (WO) xenon images. The regional ventilation in structural abnormalities was visually categorized into four patterns by consensus of two experienced radiologists who compared the xenon attenuation of structural abnormalities with that of adjacent normal parenchyma in the WI and WO images, and it served as the reference. Two series of image datasets of structural abnormalities were randomly extracted for optimization and validation. The proportion of agreement on a per-lesion basis and receiver operating characteristics on a per-pixel basis between CAC and reference were analyzed for optimization. Thereafter, six readers independently categorized the regional ventilation in structural abnormalities in the validation set without and with a CAC map. Interobserver agreement was also compared between assessments without and with CAC maps using multirater κ statistics. Results Computer-aided classification maps were successfully generated in 31 patients (81.5%). The proportion of agreement and the average area under the curve of optimized CAC maps were 94% (75/80) and 0.994, respectively. Multirater κ value was improved from moderate (κ = 0.59; 95% confidence interval [CI], 0.56-0.62) at the initial assessment to excellent (κ = 0.82; 95% CI, 0.79-0.85) with the CAC map. Conclusion Our proposed CAC system demonstrated the potential for regional ventilation pattern analysis and enhanced interobserver agreement on visual classification of regional ventilation. PMID:24843245

Computer-aided classification of visual ventilation patterns in patients with chronic obstructive pulmonary disease at two-phase xenon-enhanced CT.

PubMed

Yoon, Soon Ho; Goo, Jin Mo; Jung, Julip; Hong, Helen; Park, Eun Ah; Lee, Chang Hyun; Lee, Youkyung; Jin, Kwang Nam; Choo, Ji Yung; Lee, Nyoung Keun

2014-01-01

To evaluate the technical feasibility, performance, and interobserver agreement of a computer-aided classification (CAC) system for regional ventilation at two-phase xenon-enhanced CT in patients with chronic obstructive pulmonary disease (COPD). Thirty-eight patients with COPD underwent two-phase xenon ventilation CT with resulting wash-in (WI) and wash-out (WO) xenon images. The regional ventilation in structural abnormalities was visually categorized into four patterns by consensus of two experienced radiologists who compared the xenon attenuation of structural abnormalities with that of adjacent normal parenchyma in the WI and WO images, and it served as the reference. Two series of image datasets of structural abnormalities were randomly extracted for optimization and validation. The proportion of agreement on a per-lesion basis and receiver operating characteristics on a per-pixel basis between CAC and reference were analyzed for optimization. Thereafter, six readers independently categorized the regional ventilation in structural abnormalities in the validation set without and with a CAC map. Interobserver agreement was also compared between assessments without and with CAC maps using multirater κ statistics. Computer-aided classification maps were successfully generated in 31 patients (81.5%). The proportion of agreement and the average area under the curve of optimized CAC maps were 94% (75/80) and 0.994, respectively. Multirater κ value was improved from moderate (κ = 0.59; 95% confidence interval [CI], 0.56-0.62) at the initial assessment to excellent (κ = 0.82; 95% CI, 0.79-0.85) with the CAC map. Our proposed CAC system demonstrated the potential for regional ventilation pattern analysis and enhanced interobserver agreement on visual classification of regional ventilation.

Comparison of different coil positions for ventilation monitoring with contact-less magnetic impedance measurements

NASA Astrophysics Data System (ADS)

Cordes, A.; Pollig, D.; Leonhardt, S.

2010-04-01

For monitoring the health status of individuals, proper monitoring of ventilation is desirable. Therefore, a continuous measurement technique is an advantage for many patients since it allows personal home care scenarios. As an example, monitoring of elderly people at home could enable them to live in their familiar environment on their own with the safety of a continuous monitoring. Therefore, a measurement technique without the restriction of mobility is required. Since it is possible to monitor ventilation with magnetic impedance measurements without conductive contact, this technique is well suited for the mentioned scenario. Integrated in a chair, a person's health state could be monitored in many situations, e.g. during meals, while watching TV or reading a book. In this paper, we compare different positions of coil arrays for a magnetic impedance measurement system integrated in a chair in order to monitor ventilation continuously. For limiting the costs and technical complexity of the magnetic impedance measurement system, we have a focus on coil configurations with one RF channel. To limit the needed space and thickness of the array in the backrest, planar gradiometer coil setups are investigated. All measurements will be performed with a new developed portable magnetic impedance measurement system and a standard office chair.

Design and Control of a Mechatronic Tracheostomy Tube for Automated Tracheal Suctioning.

PubMed

Do, Thanh Nho; Seah, Tian En Timothy; Phee, Soo Jay

2016-06-01

Mechanical ventilation is required to aid patients with breathing difficulty to breathe more comfortably. A tracheostomy tube inserted through an opening in the patient neck into the trachea is connected to a ventilator for suctioning. Currently, nurses spend millions of person-hours yearly to perform this task. To save significant person-hours, an automated mechatronic tracheostomy system is needed. This system allows for relieving nurses and other carers from the millions of person-hours spent yearly on tracheal suctioning. In addition, it will result in huge healthcare cost savings. We introduce a novel mechatronic tracheostomy system including the development of a long suction catheter, automatic suctioning mechanisms, and relevant control approaches to perform tracheal suctioning automatically. To stop the catheter at a desired position, two approaches are introduced: 1) Based on the known travel length of the catheter tip; 2) Based on a new sensing device integrated at the catheter tip. It is known that backlash nonlinearity between the suction catheter and its conduit as well as in the gear system of the actuator are unavoidable. They cause difficulties to control the exact position of the catheter tip. For the former case, we develop an approximate model of backlash and a direct inverse scheme to enhance the system performances. The scheme does not require any complex inversions of the backlash model and allows easy implementations. For the latter case, a new sensing device integrated into the suction catheter tip is developed and backlash compensation controls are avoided. Automated suctioning validations are successfully carried out on the proposed experimental system. Comparisons and discussions are also introduced. The results demonstrate a significant contribution and potential benefits to the mechanical ventilation areas.

Technology for noninvasive mechanical ventilation: looking into the black box

PubMed Central

Navajas, Daniel; Montserrat, Josep M.

2016-01-01

Current devices for providing noninvasive respiratory support contain sensors and built-in intelligence for automatically modifying ventilation according to the patient's needs. These devices, including automatic continuous positive airway pressure devices and noninvasive ventilators, are technologically complex and offer a considerable number of different modes of ventilation and setting options, the details of which are sometimes difficult to capture by the user. Therefore, better predicting and interpreting the actual performance of these ventilation devices in clinical application requires understanding their functioning principles and assessing their performance under well controlled bench test conditions with simulated patients. This concise review presents an updated perspective of the theoretical basis of intelligent continuous positive airway pressure and noninvasive ventilation devices, and of the tools available for assessing how these devices respond under specific ventilation phenotypes in patients requiring breathing support. PMID:27730162

10 CFR 433.5 - Performance level determination.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) Each Federal agency shall consider laboratory fume hoods and kitchen ventilation systems as part of the ASHRAE-covered HVAC loads subject to the 30 percent savings requirements, rather than as process loads. ...

10 CFR 433.5 - Performance level determination.

Code of Federal Regulations, 2014 CFR

2014-01-01

... loads). (b) Each Federal agency shall consider laboratory fume hoods and kitchen ventilation systems as part of the ASHRAE-covered HVAC loads subject to the 30 percent savings requirements, rather than as...

10 CFR 433.5 - Performance level determination.

Code of Federal Regulations, 2011 CFR

2011-01-01

...) Each Federal agency shall consider laboratory fume hoods and kitchen ventilation systems as part of the ASHRAE-covered HVAC loads subject to the 30 percent savings requirements, rather than as process loads. ...

Cardiopulmonary resuscitation by chest compression alone or with mouth-to-mouth ventilation.

PubMed

Hallstrom, A; Cobb, L; Johnson, E; Copass, M

2000-05-25

Despite extensive training of citizens of Seattle in cardiopulmonary resuscitation (CPR), bystanders do not perform CPR in almost half of witnessed cardiac arrests. Instructions in chest compression plus mouth-to-mouth ventilation given by dispatchers over the telephone can require 2.4 minutes. In experimental studies, chest compression alone is associated with survival rates similar to those with chest compression plus mouth-to-mouth ventilation. We conducted a randomized study to compare CPR by chest compression alone with CPR by chest compression plus mouth-to-mouth ventilation. The setting of the trial was an urban, fire-department-based, emergency-medical-care system with central dispatching. In a randomized manner, telephone dispatchers gave bystanders at the scene of apparent cardiac arrest instructions in either chest compression alone or chest compression plus mouth-to-mouth ventilation. The primary end point was survival to hospital discharge. Data were analyzed for 241 patients randomly assigned to receive chest compression alone and 279 assigned to chest compression plus mouth-to-mouth ventilation. Complete instructions were delivered in 62 percent of episodes for the group receiving chest compression plus mouth-to-mouth ventilation and 81 percent of episodes for the group receiving chest compression alone (P=0.005). Instructions for compression required 1.4 minutes less to complete than instructions for compression plus mouth-to-mouth ventilation. Survival to hospital discharge was better among patients assigned to chest compression alone than among those assigned to chest compression plus mouth-to-mouth ventilation (14.6 percent vs. 10.4 percent), but the difference was not statistically significant (P=0.18). The outcome after CPR with chest compression alone is similar to that after chest compression with mouth-to-mouth ventilation, and chest compression alone may be the preferred approach for bystanders inexperienced in CPR.

46 CFR 153.310 - Ventilation system type.

Code of Federal Regulations, 2014 CFR

2014-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a permanent...

46 CFR 153.310 - Ventilation system type.

Code of Federal Regulations, 2010 CFR

2010-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a permanent...

46 CFR 153.310 - Ventilation system type.

Code of Federal Regulations, 2012 CFR

2012-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a permanent...

46 CFR 153.310 - Ventilation system type.

Code of Federal Regulations, 2011 CFR

2011-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a permanent...

46 CFR 153.310 - Ventilation system type.

Code of Federal Regulations, 2013 CFR

2013-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a permanent...

Influence of chest compression artefact on capnogram-based ventilation detection during out-of-hospital cardiopulmonary resuscitation.

PubMed

Leturiondo, Mikel; Ruiz de Gauna, Sofía; Ruiz, Jesus M; Julio Gutiérrez, J; Leturiondo, Luis A; González-Otero, Digna M; Russell, James K; Zive, Dana; Daya, Mohamud

2018-03-01

Capnography has been proposed as a method for monitoring the ventilation rate during cardiopulmonary resuscitation (CPR). A high incidence (above 70%) of capnograms distorted by chest compression induced oscillations has been previously reported in out-of-hospital (OOH) CPR. The aim of the study was to better characterize the chest compression artefact and to evaluate its influence on the performance of a capnogram-based ventilation detector during OOH CPR. Data from the MRx monitor-defibrillator were extracted from OOH cardiac arrest episodes. For each episode, presence of chest compression artefact was annotated in the capnogram. Concurrent compression depth and transthoracic impedance signals were used to identify chest compressions and to annotate ventilations, respectively. We designed a capnogram-based ventilation detection algorithm and tested its performance with clean and distorted episodes. Data were collected from 232 episodes comprising 52 654 ventilations, with a mean (±SD) of 227 (±118) per episode. Overall, 42% of the capnograms were distorted. Presence of chest compression artefact degraded algorithm performance in terms of ventilation detection, estimation of ventilation rate, and the ability to detect hyperventilation. Capnogram-based ventilation detection during CPR using our algorithm was compromised by the presence of chest compression artefact. In particular, artefact spanning from the plateau to the baseline strongly degraded ventilation detection, and caused a high number of false hyperventilation alarms. Further research is needed to reduce the impact of chest compression artefact on capnographic ventilation monitoring. Copyright © 2017 Elsevier B.V. All rights reserved.

A Comprehensive Approach for the Ergonomic Evaluation of 13 Emergency and Transport Ventilators.

PubMed

Marjanovic, Nicolas; L'Her, Erwan

2016-05-01

Mechanical ventilation is an important part of emergency medicine and is frequently used for transportation. Human errors during ventilator settings are frequent and may be associated with high morbidity/mortality. The aim of the study was to provide a complete ergonomic evaluation of emergency and transport ventilators, taking into account objective and subjective human-machine interface assessments and individual mental work load. We performed a prospective bench ergonomic evaluation of 13 emergency and transport ventilators, using standardized conditions and a global methodological approach. The study was performed in an evaluation laboratory dedicated to respiratory care, and 12 emergency physicians unfamiliar with the tested devices were included in the evaluation. The ventilators were classified into 3 categories (simple, sophisticated, and ICU-like). Objective chronometric evaluations were conducted considering 9 tasks, and subjective evaluations were performed (ease of use, willingness to use, and user-friendliness of monitoring) using Likert scales. Mental work load evaluation was performed using the NASA Task Load Index scale. Overall task failure rate represented 4% of all attempts. Setting modifications, ventilation mode changes, and powering down durations were different between simple and other emergency and transport ventilator categories (P < .005). There was no difference between ventilator categories for the ease of use and user-friendliness of the monitoring. In contrast, the willingness to use was lower for simple devices, compared with sophisticated and ICU-like emergency and transport ventilators (2.9 ± 1.4 vs 3.9 ± 1.2, P = .002 and 4.3 ± 1, P < .001). No differences were observed between devices regarding the mental work load, except for several specific devices in the sophisticated category. A comprehensive ergonomic evaluation provides valuable information while investigating operational friendliness in emergency and transport ventilators. The choice of a device not only depends on its technical characteristics but should take into account its clinical operational setting and ergonomics in order to decrease mental work load. Sophisticated emergency and transport ventilators should only be used by clinicians who demonstrate expertise in mechanical ventilation. Copyright © 2016 by Daedalus Enterprises.

Bench performance of ventilators during simulated paediatric ventilation.

PubMed

Park, M A J; Freebairn, R C; Gomersall, C D

2013-05-01

This study compares the accuracy and capabilities of various ventilators using a paediatric acute respiratory distress syndrome lung model. Various compliance settings and respiratory rate settings were used. The study was done in three parts: tidal volume and FiO2 accuracy; pressure control accuracy and positive end-expiratory pressure (PEEP) accuracy. The parameters set on the ventilator were compared with either or both of the measured parameters by the test lung and the ventilator. The results revealed that none of the ventilators could consistently deliver tidal volumes within 1 ml/kg of the set tidal volume, and the discrepancy between the delivered volume and the volume measured by the ventilator varied greatly. The target tidal volume was 8 ml/kg, but delivered tidal volumes ranged from 3.6-11.4 ml/kg and the volumes measured by the ventilator ranged from 4.1-20.6 ml/kg. All the ventilators maintained pressure within 20% of the set pressure, except one ventilator which delivered pressures of up to 27% higher than the set pressure. Two ventilators maintained PEEP within 10% of the prescribed PEEP. The majority of the readings were also within 10%. However, three ventilators delivered, at times, PEEPs over 20% higher. In conclusion, as lung compliance decreases, especially in paediatric patients, some ventilators perform better than others. This study highlights situations where ventilators may not be able to deliver, nor adequately measure, set tidal volumes, pressure, PEEP or FiO2.

Prediction of the diffuse-field transmission loss of interior natural-ventilation openings and silencers.

PubMed

Bibby, Chris; Hodgson, Murray

2017-01-01

The work reported here, part of a study on the performance and optimal design of interior natural-ventilation openings and silencers ("ventilators"), discusses the prediction of the acoustical performance of such ventilators, and the factors that affect it. A wave-based numerical approach-the finite-element method (FEM)-is applied. The development of a FEM technique for the prediction of ventilator diffuse-field transmission loss is presented. Model convergence is studied with respect to mesh, frequency-sampling and diffuse-field convergence. The modeling technique is validated by way of predictions and the comparison of them to analytical and experimental results. The transmission-loss performance of crosstalk silencers of four shapes, and the factors that affect it, are predicted and discussed. Performance increases with flow-path length for all silencer types. Adding elbows significantly increases high-frequency transmission loss, but does not increase overall silencer performance which is controlled by low-to-mid-frequency transmission loss.

Heating, Ventilation and Air-Conditioning Systems, Part of Indoor Air Quality Design Tools for Schools

EPA Pesticide Factsheets

The main purposes of a Heating, Ventilation, and Air-Conditioning system are to help maintain good indoor air quality through adequate ventilation with filtration and provide thermal comfort. HVAC systems are among the largest energy consumers in schools.

14 CFR 252.9 - Ventilation systems.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking whenever...

14 CFR 252.9 - Ventilation systems.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking whenever...

14 CFR 252.9 - Ventilation systems.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking whenever...

14 CFR 252.9 - Ventilation systems.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking whenever...

14 CFR 252.9 - Ventilation systems.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking whenever...

Multicenter comparative study of conventional mechanical gas ventilation to tidal liquid ventilation in oleic acid injured sheep.

PubMed

Wolfson, Marla R; Hirschl, Ronald B; Jackson, J Craig; Gauvin, France; Foley, David S; Lamm, Wayne J E; Gaughan, John; Shaffer, Thomas H

2008-01-01

We performed a multicenter study to test the hypothesis that tidal liquid ventilation (TLV) would improve cardiopulmonary, lung histomorphological, and inflammatory profiles compared with conventional mechanical gas ventilation (CMV). Sheep were studied using the same volume-controlled, pressure-limited ventilator systems, protocols, and treatment strategies in three independent laboratories. Following baseline measurements, oleic acid lung injury was induced and animals were randomized to 4 hours of CMV or TLV targeted to "best PaO2" and PaCO2 35 to 60 mm Hg. The following were significantly higher (p < 0.01) during TLV than CMV: PaO2, venous oxygen saturation, respiratory compliance, cardiac output, stroke volume, oxygen delivery, ventilatory efficiency index; alveolar area, lung % gas exchange space, and expansion index. The following were lower (p < 0.01) during TLV compared with CMV: inspiratory and expiratory pause pressures, mean airway pressure, minute ventilation, physiologic shunt, plasma lactate, lung interleukin-6, interleukin-8, myeloperoxidase, and composite total injury score. No significant laboratories by treatment group interactions were found. In summary, TLV resulted in improved cardiopulmonary physiology at lower ventilatory requirements with more favorable histological and inflammatory profiles than CMV. As such, TLV offers a feasible ventilatory alternative as a lung protective strategy in this model of acute lung injury.

Ventilation rates in recently constructed U.S. school classrooms.

PubMed

Batterman, S; Su, F-C; Wald, A; Watkins, F; Godwin, C; Thun, G

2017-09-01

Low ventilation rates (VRs) in schools have been associated with absenteeism, poorer academic performance, and teacher dissatisfaction. We measured VRs in 37 recently constructed or renovated and mechanically ventilated U.S. schools, including LEED and EnergyStar-certified buildings, using CO 2 and the steady-state, build-up, decay, and transient mass balance methods. The transient mass balance method better matched conditions (specifically, changes in occupancy) and minimized biases seen in the other methods. During the school day, air change rates (ACRs) averaged 2.0±1.3 hour -1 , and only 22% of classrooms met recommended minimum ventilation rates. HVAC systems were shut off at the school day close, and ACRs dropped to 0.21±0.19 hour -1 . VRs did not differ by building type, although cost-cutting and comfort measures resulted in low VRs and potentially impaired IAQ. VRs were lower in schools that used unit ventilators or radiant heating, in smaller schools and in larger classrooms. The steady-state, build-up, and decay methods had significant limitations and biases, showing the need to confirm that these methods are appropriate. Findings highlight the need to increase VRs and to ensure that energy saving and comfort measures do not compromise ventilation and IAQ. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Influence of Courtyard Ventilation on Thermal Performance of Office Building in Hot-Humid Climate: A Case Study

NASA Astrophysics Data System (ADS)

Abbaas, Esra'a. Sh.; Saif, Ala'eddin A.; Munaaim, MAC; Azree Othuman Mydin, Md.

2018-03-01

The influence of courtyard on the thermal performance of Development Department office building in University Malaysia Perlis (UniMAP, Pauh Putra campus) is investigated through simulation study for the effect of ventilation on indoor air temperature and relative humidity of the building. The study is carried out using EnergyPlus simulator interface within OpenStudio and SketchUp plug in software to measure both of air temperature and relative humidity hourly on 21 April 2017 as a design day. The results show that the ventilation through the windows facing the courtyard has sufficient effect on reducing the air temperature compared to the ventilation through external windows since natural ventilation is highly effective on driving the indoor warm air out to courtyard. In addition, the relative humidity is reduced due to ventilation since the courtyard has high ability to remove or dilute indoor airborne pollutants coming from indoor sources. This indicates that the presence of courtyard is highly influential on thermal performance of the building.

Inspiratory capacity at inflation hold in ventilated newborns: a surrogate measure for static compliance of the respiratory system.

PubMed

Hentschel, Roland; Semar, Nicole; Guttmann, Josef

2012-09-01

To study appropriateness of respiratory system compliance calculation using an inflation hold and compare it with ventilator readouts of pressure and tidal volume as well as with measurement of compliance of the respiratory system with the single-breath-single-occlusion technique gained with a standard lung function measurement. Prospective clinical trial. Level III neonatal unit of a university hospital. Sixty-seven newborns, born prematurely or at term, ventilated for a variety of pathologic conditions. A standardized sigh maneuver with a predefined peak inspiratory pressure of 30 cm H2O, termed inspiratory capacity at inflation hold, was applied. Using tidal volume, exhaled from inspiratory pause down to ambient pressure, as displayed by the ventilator, and predefined peak inspiratory pressure, compliance at inspiratory capacity at inflation hold conditions could be calculated as well as ratio of tidal volume and ventilator pressure using tidal volume and differential pressure at baseline ventilator settings: peak inspiratory pressure minus positive end-expiratory pressure. For the whole cohort, the equation for the regression between tidal volume at inspiratory capacity at inflation hold and compliance of the respiratory system was: compliance of the respiratory system = 0.052 * tidal volume at inspiratory capacity at inflation hold - 0.113, and compliance at inspiratory capacity at inflation hold conditions was closely related to the standard lung function measurement method of compliance of the respiratory system (R = 0.958). In contrast, ratio of tidal volume and ventilator pressure per kilogram calculated from the ventilator readouts and displayed against compliance of the respiratory system per kilogram yielded a broad scatter throughout the whole range of compliance; both were only weakly correlated (R = 0.309) and also the regression line was significantly different from the line of identity (p < .05). Peak inspiratory pressure at study entry did not affect the correlation between compliance at inspiratory capacity at inflation hold conditions and compliance of the respiratory system. After a standard sigh maneuver, inspiratory capacity at inflation hold and the derived quantity compliance at inspiratory capacity at inflation hold conditions can be regarded as a valid, accurate, and reliable surrogate measure for standard compliance of the respiratory system in contrast to ratio of tidal volume and ventilator pressure calculated from the ventilator readouts during ongoing mechanical ventilation at respective ventilator settings.

High-Performance Computing Data Center Power Usage Effectiveness |

Science.gov Websites

Power Usage Effectiveness When the Energy Systems Integration Facility (ESIF) was conceived, NREL set an , ventilation, and air conditioning (HVAC), which captures fan walls, fan coils that support the data center

Plutonium Finishing Plant (PFP) HVAC System Component Index

DOE Office of Scientific and Technical Information (OSTI.GOV)

DICK, J.D.

2000-02-28

The Plutonium Finishing Plant (PFP) WAC System includes sub-systems 25A through 25K. Specific system boundaries and justifications are contained in HNF-SD-CP-SDD-005, ''Definition and Means of Maintaining the Ventilation System Confinement Portion of the PFP Safety Envelope.'' The procurement requirements associated with the system necessitates procurement of some system equipment as Commercial Grade Items in accordance with HNF-PRO-268, ''Control of Purchased Items and Services.'' This document lists safety class and safety significant components for the Heating Ventilation Air Conditioning and specifies the critical characteristics for Commercial Grade Items, as required by HNF-PRO-268 and HNF-PRO-1819. These are the minimum specifications that themore » equipment must meet in order to properly perform its safety function. There may be several manufacturers or models that meet the critical characteristics for any one item.« less

Ventilation planning at Energy West's Deer Creek mine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tonc, L.; Prosser, B.; Gamble, G.

2009-08-15

In 2004 ventilation planning was initiated to exploit a remote area of Deer Creek mine's reserve (near Huntington, Utah), the Mill Fork Area, located under a mountain. A push-pull ventilation system was selected. This article details the design process of the ventilation system upgrade, the procurement process for the new fans, and the new fan startup testing. 5 figs., 1 photo.

77 FR 58421 - Model Safety Evaluation for Plant-Specific Adoption of Technical Specifications Task Force...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-20

... Ventilation System Surveillance Requirements To Operate for 10 Hours per Month,'' Using the Consolidated Line... currently require operating the ventilation system for at least 10 continuous hours with the heaters... Technical Specifications (TSs) Task Force (TSTF) Traveler TSTF-522, Revision 0, ``Revise Ventilation System...

46 CFR 108.437 - Pipe sizes and discharge rates for enclosed ventilation systems for rotating electrical equipment.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Pipe sizes and discharge rates for enclosed ventilation... Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.437 Pipe sizes and discharge rates for enclosed ventilation systems for rotating electrical equipment. (a) The minimum pipe size for the initial...

The use of tracheostomy speaking valves in mechanically ventilated patients results in improved communication and does not prolong ventilation time in cardiothoracic intensive care unit patients.

PubMed

Sutt, Anna-Liisa; Cornwell, Petrea; Mullany, Daniel; Kinneally, Toni; Fraser, John F

2015-06-01

The aim of this study was to assess the effect of the introduction of in-line tracheostomy speaking valves (SVs) on duration of mechanical ventilation and time to verbal communication in patients requiring tracheostomy for prolonged mechanical ventilation in a predominantly cardiothoracic intensive care unit (ICU). We performed a retrospective preobservational-postobservational study using data from the ICU clinical information system and medical record. Extracted data included demographics, diagnoses and disease severity, mechanical ventilation requirements, and details on verbal communication and oral intake. Data were collected on 129 patients. Mean age was 59 ± 16 years, with 75% male. Demographics, case mix, and median time from intubation to tracheostomy (6 days preimplementation-postimplementation) were unchanged between timepoints. A significant decrease in time from tracheostomy to establishing verbal communication was observed (18 days preimplementation and 9 days postimplementation, P <.05). There was no difference in length of mechanical ventilation (20 days preimplementation-post) or time to decannulation (14 days preimplementation-postimplementation). No adverse events were documented in relation to the introduction of in-line SVs. In-line SVs were successfully implemented in mechanically ventilated tracheostomized patient population. This resulted in earlier verbal communication, no detrimental effect on ventilator weaning times, and no change in decannulation times. The purpose of the study was to compare tracheostomy outcomes in mechanically ventilated patients in a cardiothoracic ICU preintroduction and postintroduction of in-line SVs. It was hypothesized that in-line SVs would improve communication and swallowing specific outcomes with no increase in average time to decannulation or the number of adverse events. Copyright © 2015 Elsevier Inc. All rights reserved.

Numerical simulation and comparison of two ventilation methods for a restaurant - displacement vs mixed flow ventilation

NASA Astrophysics Data System (ADS)

Chitaru, George; Berville, Charles; Dogeanu, Angel

2018-02-01

This paper presents a comparison between a displacement ventilation method and a mixed flow ventilation method using computational fluid dynamics (CFD) approach. The paper analyses different aspects of the two systems, like the draft effect in certain areas, the air temperatureand velocity distribution in the occupied zone. The results highlighted that the displacement ventilation system presents an advantage for the current scenario, due to the increased buoyancy driven flows caused by the interior heat sources. For the displacement ventilation case the draft effect was less prone to appear in the occupied zone but the high heat emissions from the interior sources have increased the temperature gradient in the occupied zone. Both systems have been studied in similar conditions, concentrating only on the flow patterns for each case.

Simulation of erosion by a particulate airflow through a ventilator

NASA Astrophysics Data System (ADS)

Ghenaiet, A.

2015-08-01

Particulate flows are a serious problem in air ventilation systems, leading to erosion of rotor blades and aerodynamic performance degradation. This paper presents the numerical results of sand particle trajectories and erosion patterns in an axial ventilator and the subsequent blade deterioration. The flow field was solved separately by using the code CFX- TASCflow. The Lagrangian approach for the solid particles tracking implemented in our inhouse code considers particle and eddy interaction, particle size distribution, particle rebounds and near walls effects. The assessment of erosion wear is based on the impact frequency and local values of erosion rate. Particle trajectories and erosion simulation revealed distinctive zones of impacts with high rates of erosion mainly on the blade pressure side, whereas the suction side is eroded around the leading edge.

Infection prevention during anaesthesia ventilation by the use of breathing system filters (BSF): Joint recommendation by German Society of Hospital Hygiene (DGKH) and German Society for Anaesthesiology and Intensive Care (DGAI)

PubMed Central

Kramer, Axel; Kranabetter, Rainer; Rathgeber, Jörg; Züchner, Klaus; Assadian, Ojan; Daeschlein, Georg; Hübner, Nils-Olaf; Dietlein, Edeltrut; Exner, Martin; Gründling, Matthias; Lehmann, Christian; Wendt, Michael; Graf, Bernhard Martin; Holst, Dietmar; Jatzwauk, Lutz; Puhlmann, Birgit; Welte, Thomas; Wilkes, Antony R.

2010-01-01

An interdisciplinary working group from the German Society of Hospital Hygiene (DGKH) and the German Society for Anaesthesiology and Intensive Care (DGAI) worked out the following recommendations for infection prevention during anaesthesia by using breathing system filters (BSF). The BSF shall be changed after each patient. The filter retention efficiency for airborne particles is recommended to be >99% (II). The retention performance of BSF for liquids is recommended to be at pressures of at least 60 hPa (=60 mbar) or 20 hPa above the selected maximum ventilation pressure in the anaesthetic system. The anaesthesia breathing system may be used for a period of up to 7 days provided that the functional requirements of the system remain unchanged and the manufacturer states this in the instructions for use. The breathing system and the manual ventilation bag are changed immediately after the respective anaesthesia if the following situation has occurred or it is suspected to have occurred: Notifiable infectious disease involving the risk of transmission via the breathing system and the manual bag, e.g. tuberculosis, acute viral hepatitis, measles, influenza virus, infection and/or colonisation with a multi-resistant pathogen or upper or lower respiratory tract infections. In case of visible contamination e.g. by blood or in case of defect, it is required that the BSF and also the anaesthesia breathing system is changed and the breathing gas conducting parts of the anaesthesia ventilator are hygienically reprocessed. Observing of the appropriate hand disinfection is very important. All surfaces of the anaesthesia equipment exposed to hand contact must be disinfected after each case. PMID:20941333

Infection prevention during anaesthesia ventilation by the use of breathing system filters (BSF): Joint recommendation by German Society of Hospital Hygiene (DGKH) and German Society for Anaesthesiology and Intensive Care (DGAI).

PubMed

Kramer, Axel; Kranabetter, Rainer; Rathgeber, Jörg; Züchner, Klaus; Assadian, Ojan; Daeschlein, Georg; Hübner, Nils-Olaf; Dietlein, Edeltrut; Exner, Martin; Gründling, Matthias; Lehmann, Christian; Wendt, Michael; Graf, Bernhard Martin; Holst, Dietmar; Jatzwauk, Lutz; Puhlmann, Birgit; Welte, Thomas; Wilkes, Antony R

2010-09-21

An interdisciplinary working group from the German Society of Hospital Hygiene (DGKH) and the German Society for Anaesthesiology and Intensive Care (DGAI) worked out the following recommendations for infection prevention during anaesthesia by using breathing system filters (BSF). The BSF shall be changed after each patient. The filter retention efficiency for airborne particles is recommended to be >99% (II). The retention performance of BSF for liquids is recommended to be at pressures of at least 60 hPa (=60 mbar) or 20 hPa above the selected maximum ventilation pressure in the anaesthetic system. The anaesthesia breathing system may be used for a period of up to 7 days provided that the functional requirements of the system remain unchanged and the manufacturer states this in the instructions for use.THE BREATHING SYSTEM AND THE MANUAL VENTILATION BAG ARE CHANGED IMMEDIATELY AFTER THE RESPECTIVE ANAESTHESIA IF THE FOLLOWING SITUATION HAS OCCURRED OR IT IS SUSPECTED TO HAVE OCCURRED: Notifiable infectious disease involving the risk of transmission via the breathing system and the manual bag, e.g. tuberculosis, acute viral hepatitis, measles, influenza virus, infection and/or colonisation with a multi-resistant pathogen or upper or lower respiratory tract infections. In case of visible contamination e.g. by blood or in case of defect, it is required that the BSF and also the anaesthesia breathing system is changed and the breathing gas conducting parts of the anaesthesia ventilator are hygienically reprocessed.Observing of the appropriate hand disinfection is very important. All surfaces of the anaesthesia equipment exposed to hand contact must be disinfected after each case.

HPAC Info-dex 5: Locating engineering societies, associations

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-06-01

This is the 1995/1996 listing of heating, ventilation, air conditioning and refrigeration systems engineering societies, trade associations, and government organizations that have established performance standards for mechanical systems and components. The societies and associations are listed alphabetically along with their complete addresses and telephone and FAX numbers.

VLT enclosures: design and construction

NASA Astrophysics Data System (ADS)

Schneermann, Michael W.; Marchiori, Gianpietro; Dimichino, Francesco

1997-03-01

The VLT enclosures main functions are to protect the telescopes during operational as well as non-operational phases from any adverse weather conditions and to provide optimal conditions for observation. An adequate design of a ventilation and wind protection system is important for the performance of the enclosures with respect to the minimization of the corresponding seeing effects. The VLT enclosures are equipped with ventilation doors on the azimuth platform level, with louvers on the rotating part and with a windscreen at the observing slit. Extensive qualification tests of the louvers and windscreen mechanical assemblies have been performed during the enclosures development phase. This paper gives an overview over the general layout of the enclosures and the major subsystems, summarizes the main functional specifications and gives the main results and conclusions of the functional performance tests. Presently the first enclosure erection is nearing its completion and pre- commissioning of all systems will commence. The status of the site erection of the enclosures is presented and the planning for the next phases of the erection is presented.

A preliminary study on the association between ventilation rates in classrooms and student performance.

PubMed

Shaughnessy, R J; Haverinen-Shaughnessy, U; Nevalainen, A; Moschandreas, D

2006-12-01

Poor conditions leading to substandard indoor air quality (IAQ) in classrooms have been frequently cited in the literature over the past two decades. However, there is limited data linking poor IAQ in the classrooms to student performance. Whereas, it is assumed that poor IAQ results in reduced attendance and learning potential, and subsequent poor student performance, validating this hypothesis presents a challenge in today's school environment. This study explores the association between student performance on standardized aptitude tests that are administered to students on a yearly basis, to classroom carbon dioxide (CO2) concentrations, which provide a surrogate of ventilation being provided to each room. Data on classroom CO2 concentrations (over a 4-5 h time span within a typical school day) were recorded in fifth grade classrooms in 54 elementary schools within a school district in the USA. Results from this preliminary study yield a significant (P < 0.10) association between classroom-level ventilation rate and test results in math. They also indicate that non-linear effects may need to be considered for better representation of the association. A larger sample size is required in order to draw more definitive conclusions. Practical Implications Future studies could focus on (1) gathering more evidence on the possible association between classroom ventilation rates and students' academic performance; (2) the linear/non-linear nature of the association; and (3) whether it is possible to detect 'no observed adverse effect level' for adequate ventilation with respect to academic performance in schools. All of this information could be used to improve guidance and take regulatory actions to ensure adequate ventilation in schools. The high prevalence of low ventilation rates, combined with the growing evidence of the positive impact that sufficient ventilation has on human performance, suggests an opportunity for improving design and management of school facilities.

Academic Emergency Medicine Physicians' Knowledge of Mechanical Ventilation.

PubMed

Wilcox, Susan R; Strout, Tania D; Schneider, Jeffrey I; Mitchell, Patricia M; Smith, Jessica; Lutfy-Clayton, Lucienne; Marcolini, Evie G; Aydin, Ani; Seigel, Todd A; Richards, Jeremy B

2016-05-01

Although emergency physicians frequently intubate patients, management of mechanical ventilation has not been emphasized in emergency medicine (EM) education or clinical practice. The objective of this study was to quantify EM attendings' education, experience, and knowledge regarding mechanical ventilation in the emergency department. We developed a survey of academic EM attendings' educational experiences with ventilators and a knowledge assessment tool with nine clinical questions. EM attendings at key teaching hospitals for seven EM residency training programs in the northeastern United States were invited to participate in this survey study. We performed correlation and regression analyses to evaluate the relationship between attendings' scores on the assessment instrument and their training, education, and comfort with ventilation. Of 394 EM attendings surveyed, 211 responded (53.6%). Of respondents, 74.5% reported receiving three or fewer hours of ventilation-related education from EM sources over the past year and 98 (46%) reported receiving between 0-1 hour of education. The overall correct response rate for the assessment tool was 73.4%, with a standard deviation of 19.9. The factors associated with a higher score were completion of an EM residency, prior emphasis on mechanical ventilation during one's own residency, working in a setting where an emergency physician bears primary responsibility for ventilator management, and level of comfort with managing ventilated patients. Physicians' comfort was associated with the frequency of ventilator changes and EM management of ventilation, as well as hours of education. EM attendings report caring for mechanically ventilated patients frequently, but most receive fewer than three educational hours a year on mechanical ventilation, and nearly half receive 0-1 hour. Physicians' performance on an assessment tool for mechanical ventilation is most strongly correlated with their self-reported comfort with mechanical ventilation.

Quantification and visualization of relative local ventilation on dynamic chest radiographs

NASA Astrophysics Data System (ADS)

Tanaka, Rie; Sanada, Shigeru; Okazaki, Nobuo; Kobayashi, Takeshi; Nakayama, Kazuya; Matsui, Takeshi; Hayashi, Norio; Matsui, Osamu

2006-03-01

Recently-developed dynamic flat-panel detector (FPD) with a large field of view is possible to obtain breathing chest radiographs, which provide respiratory kinetics information. This study was performed to investigate the ability of dynamic chest radiography using FPD to quantify relative ventilation according to respiratory physiology. We also reported the results of primary clinical study and described the possibility of clinical use of our method. Dynamic chest radiographs of 12 subjects involving abnormal subjects during respiration were obtained using a modified FPD system (30 frames in 10 seconds). Imaging was performed in three different positions (standing, and right and left decubitus positions) to change the distribution of local ventilation by changing the lung's own gravity in each area. The distance from the lung apex to the diaphragm (abbr. DLD) was measured by the edge detection technique for use as an index of respiratory phase. We measured pixel values in each lung area and calculated correlation coefficients with DLD. Differences in the pixel values between the maximum inspiratory and expiratory frame were calculated, and the trend of distribution was evaluated by two-way analysis of variance. Pixel value in each lung area was strongly associated with respiratory phase and its time variation and distribution were consistent with known properties in respiratory physiology. Dynamic chest radiography using FPD combined with our computerized methods was capable of quantifying relative amount of ventilation during respiration, and of detecting regional differences in ventilation. In the subjects with emphysema, areas with decreased respiratory changes in pixel value are consisted with the areas with air trapping. This method is expected to be a useful novel diagnostic imaging method for supporting diagnosis and follow-up of pulmonary disease, which presents with abnormalities in local ventilation.

Coupling of three-dimensional field and human thermoregulatory models in a crowded enclosure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xue, H.; Kang, Z.J.; Bong, T.Y.

1999-11-12

Health, comfort, and energy conservation are important factors to consider in the design of a building and its HVAC systems. Advanced tools are required to evaluate parameters regarding airflow, temperature, and humidity ratio in buildings, with the end results being better indoor air quality and thermal environment as well as increased confidence in the performance of buildings. A numerical model coupling the three-dimensional field and human thermoregulatory models is proposed and developed. A high-Re {kappa}-{epsilon} turbulence model is used for the field simulation. A modified 25-mode model of human thermoregulation is adopted to predict human thermal response in physiological parameters,more » such as body temperature and body heat loss. Distributions of air velocity, temperature, and moisture content are demonstrated in a crowded enclosure with mechanical ventilation under two ventilation rates. The results are analyzed and discussed. The coupling model is useful in assisting and verifying ventilation and air-conditioning system designs.« less

Inhibition of forkhead boxO-specific transcription prevents mechanical ventilation-induced diaphragm dysfunction.

PubMed

Smuder, Ashley J; Sollanek, Kurt J; Min, Kisuk; Nelson, W Bradley; Powers, Scott K

2015-05-01

Mechanical ventilation is a lifesaving measure for patients with respiratory failure. However, prolonged mechanical ventilation results in diaphragm weakness, which contributes to problems in weaning from the ventilator. Therefore, identifying the signaling pathways responsible for mechanical ventilation-induced diaphragm weakness is essential to developing effective countermeasures to combat this important problem. In this regard, the forkhead boxO family of transcription factors is activated in the diaphragm during mechanical ventilation, and forkhead boxO-specific transcription can lead to enhanced proteolysis and muscle protein breakdown. Currently, the role that forkhead boxO activation plays in the development of mechanical ventilation-induced diaphragm weakness remains unknown. This study tested the hypothesis that mechanical ventilation-induced increases in forkhead boxO signaling contribute to ventilator-induced diaphragm weakness. University research laboratory. Young adult female Sprague-Dawley rats. Cause and effect was determined by inhibiting the activation of forkhead boxO in the rat diaphragm through the use of a dominant-negative forkhead boxO adeno-associated virus vector delivered directly to the diaphragm. Our results demonstrate that prolonged (12 hr) mechanical ventilation results in a significant decrease in both diaphragm muscle fiber size and diaphragm-specific force production. However, mechanically ventilated animals treated with dominant-negative forkhead boxO showed a significant attenuation of both diaphragm atrophy and contractile dysfunction. In addition, inhibiting forkhead boxO transcription attenuated the mechanical ventilation-induced activation of the ubiquitin-proteasome system, the autophagy/lysosomal system, and caspase-3. Forkhead boxO is necessary for the activation of key proteolytic systems essential for mechanical ventilation-induced diaphragm atrophy and contractile dysfunction. Collectively, these results suggest that targeting forkhead boxO transcription could be a key therapeutic target to combat ventilator-induced diaphragm dysfunction.

The effect of helium-oxygen-assisted mechanical ventilation on chronic obstructive pulmonary disease exacerbation: A systemic review and meta-analysis.

PubMed

Wu, Xu; Shao, Chuan; Zhang, Liang; Tu, Jinjing; Xu, Hui; Lin, Zhihui; Xu, Shuguang; Yu, Biyun; Tang, Yaodong; Li, Shanqun

2018-03-01

Chronic obstructive pulmonary disease (COPD) is often accompanied by acute exacerbations. Patients of COPD exacerbation suffering from respiratory failure often need the support of mechanical ventilation. Helium-oxygen can be used to reduce airway resistance during mechanical ventilation. The aim of this study is to evaluate the effect of helium-oxygen-assisted mechanical ventilation on COPD exacerbation through a meta-analysis. A comprehensive literature search through databases of Pub Med (1966∼2016), Ovid MEDLINE (1965∼2016), Cochrane EBM (1991∼2016), EMBASE (1974∼2016) and Ovid MEDLINE was performed to identify associated studies. Randomized clinical trials met our inclusion criteria that focus on helium-oxygen-assisted mechanical ventilation on COPD exacerbation were included. The quality of the papers was evaluated after inclusion and information was extracted for meta-analysis. Six articles and 392 patients were included in total. Meta-analysis revealed that helium-oxygen-assisted mechanical ventilation reduced Borg dyspnea scale and increased arterial PH compared with air-oxygen. No statistically significant difference was observed between helium-oxygen and air-oxygen as regards to WOB, PaCO 2 , OI, tracheal intubation rates and mortality within hospital. Our study suggests helium-oxygen-assisted mechanical ventilation can help to reduce Borg dyspnea scale. In terms of the tiny change of PH, its clinical benefit is negligible. There is no conclusive evidence indicating the beneficial effect of helium-oxygen-assisted mechanical ventilation on clinical outcomes or prognosis of COPD exacerbation. © 2017 John Wiley & Sons Ltd.

Outcomes management of mechanically ventilated patients: utilizing informatics technology.

PubMed

Smith, K R

1998-11-01

This article examines an informatics system developed for outcomes management of the mechanically ventilated adult population, focusing on weaning the patient from mechanical ventilation. The link between medical informatics and outcomes management is discussed, along with the development of methods, tools, and data sets for outcomes management of the mechanically ventilated adult population at an acute care academic institution. Pros and cons of this system are identified, and specific areas for improvement of future health care outcomes medical informatics systems are discussed.

B-Plant Canyon Ventilation Control System Description

DOE Office of Scientific and Technical Information (OSTI.GOV)

MCDANIEL, K.S.

1999-08-31

Project W-059 installed a new B Plant Canyon Ventilation System. Monitoring and control of the system is implemented by the Canyon Ventilation Control System (CVCS). This document describes the CVCS system components which include a Programmable Logic Controller (PLC) coupled with an Operator Interface Unit (OIU) and application software. This document also includes an Alarm Index specifying the setpoints and technical basis for system analog and digital alarms.

Evaluating humidity recovery efficiency of currently available heat and moisture exchangers: a respiratory system model study.

PubMed

Lucato, Jeanette Janaina Jaber; Adams, Alexander Bernard; Souza, Rogério; Torquato, Jamili Anbar; Carvalho, Carlos Roberto Ribeiro; Marini, John J

2009-01-01

To evaluate and compare the efficiency of humidification in available heat and moisture exchanger models under conditions of varying tidal volume, respiratory rate, and flow rate. Inspired gases are routinely preconditioned by heat and moisture exchangers to provide a heat and water content similar to that provided normally by the nose and upper airways. The absolute humidity of air retrieved from and returned to the ventilated patient is an important measurable outcome of the heat and moisture exchangers' humidifying performance. Eight different heat and moisture exchangers were studied using a respiratory system analog. The system included a heated chamber (acrylic glass, maintained at 37 degrees C), a preserved swine lung, a hygrometer, circuitry and a ventilator. Humidity and temperature levels were measured using eight distinct interposed heat and moisture exchangers given different tidal volumes, respiratory frequencies and flow-rate conditions. Recovery of absolute humidity (%RAH) was calculated for each setting. Increasing tidal volumes led to a reduction in %RAH for all heat and moisture exchangers while no significant effect was demonstrated in the context of varying respiratory rate or inspiratory flow. Our data indicate that heat and moisture exchangers are more efficient when used with low tidal volume ventilation. The roles of flow and respiratory rate were of lesser importance, suggesting that their adjustment has a less significant effect on the performance of heat and moisture exchangers.

Active noise attenuation in ventilation windows.

PubMed

Huang, Huahua; Qiu, Xiaojun; Kang, Jian

2011-07-01

The feasibility of applying active noise control techniques to attenuate low frequency noise transmission through a natural ventilation window into a room is investigated analytically and experimentally. The window system is constructed by staggering the opening sashes of a spaced double glazing window to allow ventilation and natural light. An analytical model based on the modal expansion method is developed to calculate the low frequency sound field inside the window and the room and to be used in the active noise control simulations. The effectiveness of the proposed analytical model is validated by using the finite element method. The performance of the active control system for a window with different source and receiver configurations are compared, and it is found that the numerical and experimental results are in good agreement and the best result is achieved when the secondary sources are placed in the center at the bottom of the staggered window. The extra attenuation at the observation points in the optimized window system is almost equivalent to the noise reduction at the error sensor and the frequency range of effective control is up to 390 Hz in the case of a single channel active noise control system. © 2011 Acoustical Society of America

Reducing patients' exposures to asthma and allergy triggers in their homes: an evaluation of effectiveness of grades of forced air ventilation filters.

PubMed

Brown, Kathleen Ward; Minegishi, Taeko; Allen, Joseph G; McCarthy, John F; Spengler, John D; MacIntosh, David L

2014-08-01

Many interventions to reduce allergen levels in the home are recommended to asthma and allergy patients. One that is readily available and can be highly effective is the use of high performing filters in forced air ventilation systems. We conducted a modeling analysis of the effectiveness of filter-based interventions in the home to reduce airborne asthma and allergy triggers. This work used "each pass removal efficiency" applied to health-relevant size fractions of particles to assess filter performance. We assessed effectiveness for key allergy and asthma triggers based on applicable particle sizes for cat allergen, indoor and outdoor sources of particles <2.5 µm in diameter (PM2.5), and airborne influenza and rhinovirus. Our analysis finds that higher performing filters can have significant impacts on indoor particle pollutant levels. Filters with removal efficiencies of >70% for cat dander particles, fine particulate matter (PM2.5) and respiratory virus can lower concentrations of those asthma triggers and allergens in indoor air of the home by >50%. Very high removal efficiency filters, such as those rated a 16 on the nationally recognized Minimum Efficiency Removal Value (MERV) rating system, tend to be only marginally more effective than MERV12 or 13 rated filters. The results of this analysis indicate that use of a MERV12 or higher performing air filter in home ventilation systems can effectively reduce indoor levels of these common asthma and allergy triggers. These reductions in airborne allergens in turn may help reduce allergy and asthma symptoms, especially if employed in conjunction with other environmental management measures recommended for allergy and asthma patients.

Reducing patients’ exposures to asthma and allergy triggers in their homes: an evaluation of effectiveness of grades of forced air ventilation filters

PubMed Central

Minegishi, Taeko; Allen, Joseph G.; McCarthy, John F.; Spengler, John D.; MacIntosh, David L.

2014-01-01

Objective Many interventions to reduce allergen levels in the home are recommended to asthma and allergy patients. One that is readily available and can be highly effective is the use of high performing filters in forced air ventilation systems. Methods We conducted a modeling analysis of the effectiveness of filter-based interventions in the home to reduce airborne asthma and allergy triggers. This work used “each pass removal efficiency” applied to health-relevant size fractions of particles to assess filter performance. We assessed effectiveness for key allergy and asthma triggers based on applicable particle sizes for cat allergen, indoor and outdoor sources of particles <2.5 µm in diameter (PM2.5), and airborne influenza and rhinovirus. Results Our analysis finds that higher performing filters can have significant impacts on indoor particle pollutant levels. Filters with removal efficiencies of >70% for cat dander particles, fine particulate matter (PM2.5) and respiratory virus can lower concentrations of those asthma triggers and allergens in indoor air of the home by >50%. Very high removal efficiency filters, such as those rated a 16 on the nationally recognized Minimum Efficiency Removal Value (MERV) rating system, tend to be only marginally more effective than MERV12 or 13 rated filters. Conclusions The results of this analysis indicate that use of a MERV12 or higher performing air filter in home ventilation systems can effectively reduce indoor levels of these common asthma and allergy triggers. These reductions in airborne allergens in turn may help reduce allergy and asthma symptoms, especially if employed in conjunction with other environmental management measures recommended for allergy and asthma patients. PMID:24555523

Summarized Data of Test Space Heating, Ventilation and Air Conditioning Inspections from the Building Assessment Survey and Evaluation Study

EPA Pesticide Factsheets

Information on the characteristics of the heating, ventilation, and air conditioning (HVAC) system(s) in the entire BASE building including types of ventilation, equipment configurations, and operation and maintenance issues

Selecting HVAC Systems for Schools To Balance the Needs for Indoor Air Quality, Energy Conservation and Maintenance. Technical Bulletin.

ERIC Educational Resources Information Center

Wheeler, Arthur E.; Kunz, Walter S., Jr.

Although poor air quality in a school can have multiple causes, the heating, ventilating, and air-conditioning (HVAC) system plays a major role. Suggestions that architects, facilities managers, school board members, and administrators can use in selecting HVAC systems are discussed. Focus is on the performance criteria for classroom systems, and…

Evaluation of Passive Vents in New Construction Multifamily Buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sean Maxwell; Berger, David; Zuluaga, Marc

Exhaust ventilation and corresponding outdoor air strategies are being implemented in high performance, new construction, multifamily buildings to meet program or code requirements for improved indoor air quality, but a lack of clear design guidance is resulting in poor performance of these systems despite the best intentions of the programs or standards.

Animal biocalorimeter and waste management system

NASA Technical Reports Server (NTRS)

Poppendiek, Heinz F. (Inventor); Trimailo, William R. (Inventor)

1995-01-01

A biocalorimeter and waste management system is provided for making metabolic heat release measurements of animals or humans in a calorimeter (enclosure) using ambient air as a low velocity source of ventilating air through the enclosure. A shroud forces ventilating air to pass over the enclosure from an end open to ambient air at the end of the enclosure opposite its ventilating air inlet end and closed around the inlet end of the enclosure in order to obviate the need for regulating ambient air temperature. Psychrometers for measuring dry- and wet-bulb temperature of ventilating air make it possible to account for the sensible and latent heat additions to the ventilating air. A waste removal system momentarily recirculates high velocity air in a closed circuit through the calorimeter wherein a sudden rise in moisture is detected in the ventilating air from the outlet.

Contaminants in ventilated filling boxes

NASA Astrophysics Data System (ADS)

Bolster, D. T.; Linden, P. F.

While energy efficiency is important, the adoption of energy-efficient ventilation systems still requires the provision of acceptable indoor air quality. Many low-energy systems, such as displacement or natural ventilation, rely on temperature stratification within the interior environment, always extracting the warmest air from the top of the room. Understanding buoyancy-driven convection in a confined ventilated space is key to understanding the flow that develops with many of these modern low-energy ventilation schemes. In this work we study the transport of an initially uniformly distributed passive contaminant in a displacement-ventilated space. Representing a heat source as an ideal sourced of buoyancy, analytical and numerical models are developed that allow us to compare the average efficiency of contaminant removal between traditional mixing and modern low-energy systems. A set of small-scale analogue laboratory experiments was also conducted to further validate our analytical and numerical solutions.We find that on average traditional and low-energy ventilation methods are similar with regard to pollutant flushing efficiency. This is because the concentration being extracted from the system at any given time is approximately the same for both systems. However, very different vertical concentration gradients exist. For the low-energy system, a peak in contaminant concentration occurs at the temperature interface that is established within the space. This interface is typically designed to sit at some intermediate height in the space. Since this peak does not coincide with the extraction point, displacement ventilation does not offer the same benefits for pollutant flushing as it does for buoyancy removal.

Results of the Trace Contaminant Control Needs Evaluation and Sizing Study for Space Suit Life Support Development

NASA Technical Reports Server (NTRS)

Paul, Heather L.; Jennings, Mallory A.

2009-01-01

The Trace Contaminant Control System (TCCS), located within the ventilation loop of the Portable Life Support System (PLSS) of the Constellation Space Suit Element (CSSE), is responsible for removing hazardous trace contaminants from the space suit ventilation flow. This paper summarizes the results of a trade study that evaluated if trace contaminant control could be accomplished without a TCCS, relying on suit leakage, ullage loss from the carbon dioxide and humidity control system, and other factors. Trace contaminant generation rates were revisited to verify that values reflect the latest designs for CSSE pressure garment materials and PLSS hardware. Additionally, TCCS sizing calculations were performed and a literature survey was conducted to review the latest developments in trace contaminant technologies.

Applied patent RFID systems for building reacting HEPA air ventilation system in hospital operation rooms.

PubMed

Lin, Jesun; Pai, Jar-Yuan; Chen, Chih-Cheng

2012-12-01

RFID technology, an automatic identification and data capture technology to provide identification, tracing, security and so on, was widely applied to healthcare industry in these years. Employing HEPA ventilation system in hospital is a way to ensure healthful indoor air quality to protect patients and healthcare workers against hospital-acquired infections. However, the system consumes lots of electricity which cost a lot. This study aims to apply the RFID technology to offer a unique medical staff and patient identification, and reacting HEPA air ventilation system in order to reduce the cost, save energy and prevent the prevalence of hospital-acquired infection. The system, reacting HEPA air ventilation system, contains RFID tags (for medical staffs and patients), sensor, and reacting system which receives the information regarding the number of medical staff and the status of the surgery, and controls the air volume of the HEPA air ventilation system accordingly. A pilot program was carried out in a unit of operation rooms of a medical center with 1,500 beds located in central Taiwan from Jan to Aug 2010. The results found the air ventilation system was able to function much more efficiently with less energy consumed. Furthermore, the indoor air quality could still keep qualified and hospital-acquired infection or other occupational diseases could be prevented.

Space station ventilation study

NASA Technical Reports Server (NTRS)

Colombo, G. V.; Allen, G. E.

1972-01-01

A ventilation system design and selection method which is applicable to any manned vehicle were developed. The method was used to generate design options for the NASA 33-foot diameter space station, all of which meet the ventilation system design requirements. System characteristics such as weight, volume, and power were normalized to dollar costs for each option. Total system costs for the various options ranged from a worst case $8 million to a group of four which were all approximately $2 million. A system design was then chosen from the $2 million group and is presented in detail. A ventilation system layout was designed for the MSFC space station mockup which provided comfortable, efficient ventilation of the mockup. A conditioned air distribution system design for the 14-foot diameter modular space station, using the same techniques, is also presented. The tradeoff study resulted in the selection of a system which costs $1.9 million, as compared to the alternate configuration which would have cost $2.6 million.

Evaluation of a local exhaust system used in the manufacture of small parts made of reinforced plastic.

PubMed

Lazure, L P

2000-09-01

Fiber-reinforced plastics are used to manufacture a large variety of products, particularly for the transportation sector. Hand lay-up molding and projection molding are the main methods of manufacture. The users of these processes are exposed to appreciable emissions of styrene; in Quebec, more than 3000 workers work in this industry. A statistical analysis of styrene concentrations measured over a five-year period by the Institut de recherche en santé et en sécurité du travail (IRSST, Occupational Health and Safety Research Institute) reveals that for all of the main manufacturing sectors involved, between 40 percent and 78 percent of the results exceed the exposure standard of 50 ppm. This study evaluated the effectiveness of a ventilated table in controlling worker exposure to styrene and acetone in a shop that manufactures fiber-reinforced plastics parts. The evaluated local extraction system consists of a ventilated table with a surface area of 1.2 m x 1.2 m. During molding, the styrene emissions are exhausted through the ventilated table as well as through the slots in a lateral hood. Replacement air, introduced vertically through a supply air shower located above the worker, limits the diffusion of contaminants toward the worker's breathing zone. The reduction in worker exposure to styrene and acetone during hand lay-up molding was measured in the breathing zone for two sizes of molds. The results show that exhaust ventilation reduced the styrene concentrations by 91 percent and that the introduction of replacement air increased the efficiency of the ventilated table to 96 percent. The evaluation performed indicates that the ventilated table adequately controls worker exposure to styrene and acetone during the molding of small components.

Modelling Potential Consequences of Different Geo-Engineering Treatments for the Baltic Sea Ecosystem

NASA Astrophysics Data System (ADS)

Schrum, C.; Daewel, U.

2017-12-01

From 1950 onwards, the Baltic Sea ecosystem suffered increasingly from eutrophication. The most obvious reason for the eutrophication is the huge amount of nutrients (nitrogen and phosphorus) reaching the Baltic Sea from human activities. However, although nutrient loads have been decreasing since 1980, the hypoxic areas have not decreased accordingly. Thus, geo-engineering projects were discussed and evaluated to artificially ventilate the Baltic Sea deep water and suppress nutrient release from the sediments. Here, we aim at understanding the consequences of proposed geo-engineering projects in the Baltic Sea using long-term scenario modelling. For that purpose, we utilize a 3d coupled ecosystem model ECOSMO E2E, a novel NPZD-Fish model approach that resolves hydrodynamics, biogeochemical cycling and lower and higher trophic level dynamics. We performed scenario modelling that consider proposed geo-engineering projects such as artificial ventilation of Baltic Sea deep waters and phosphorus binding in sediments with polyaluminium chlorides. The model indicates that deep-water ventilation indeed suppresses phosphorus release in the first 1-4 years of treatment. Thereafter macrobenthos repopulates the formerly anoxic bottom regions and nutrients are increasingly recycled in the food web. Consequently, overall system productivity and fish biomass increases and toxic algae blooms decrease. However, deep-water ventilation has no long-lasting effect on the ecosystem: soon after completion of the ventilation process, the system turns back into its original state. Artificial phosphorus binding in sediments in contrast decreases overall ecosystem productivity through permanent removal of phosphorus. As expected it decreases bacterial production and toxic algae blooms, but it also decreases fish production substantially. Contrastingly to deep water ventilation, artificial phosphorus binding show a long-lasting effect over decades after termination of the treatment.

Evaluation of Rankine cycle air conditioning system hardware by computer simulation

NASA Technical Reports Server (NTRS)

Healey, H. M.; Clark, D.

1978-01-01

A computer program for simulating the performance of a variety of solar powered Rankine cycle air conditioning system components (RCACS) has been developed. The computer program models actual equipment by developing performance maps from manufacturers data and is capable of simulating off-design operation of the RCACS components. The program designed to be a subroutine of the Marshall Space Flight Center (MSFC) Solar Energy System Analysis Computer Program 'SOLRAD', is a complete package suitable for use by an occasional computer user in developing performance maps of heating, ventilation and air conditioning components.

Simulated performance of CIEE's 'Alternatives to Compressive Cooling' prototype house under design conditions in various California climates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Yu Joe

To support the design development of a compressorless house that does not rely on mechanical air-conditioning, the author carried out detailed computer analysis of a prototypical house design to determine the indoor thermal conditions during peak cooling periods for over 170 California locations. The peak cooling periods are five-day sequences at 2{percent} frequency determined through statistical analysis of long-term historical weather data. The DOE-2 program was used to simulate the indoor temperatures of the house under four operating options: windows closed, with mechanical ventilation, evaporatively-cooled mechanical ventilation, or a conventional 1 1/2-ton air conditioner. The study found that with amore » 1500 CFM mechanical ventilation system, the house design would maintain comfort under peak conditions in the San Francisco Bay Area out to Walnut Creek, but not beyond. In southern California, the same system and house design would maintain adequate comfort only along the coast. With the evaporatively-cooled ventilation system, the applicability of the house design can be extended to Fairfield and Livermore in northern California, but in southern California a larger 3000 CFM system would be needed to maintain comfort conditions over half of the greater Los Angeles area, the southern half of the Inland Empire, and most of San Diego county. With the 1 1/2-ton air conditioner, the proposed house design would perform satisfactorily through most of the state, except in the upper areas of the Central Valley and the hot desert areas in southern California. In terms of energy savings, the simulations showed that the prototypical house design would save from 0.20 to 0.43 in northern California, 0.20 to 0.53 in southern California, and 0.16 to 0.35 in the Central Valley, the energy used by the same house design built to Title-24 requirements.« less

Actual performance of mechanical ventilators in ICU: a multicentric quality control study.

PubMed

Govoni, Leonardo; Dellaca', Raffaele L; Peñuelas, Oscar; Bellani, Giacomo; Artigas, Antonio; Ferrer, Miquel; Navajas, Daniel; Pedotti, Antonio; Farré, Ramon

2012-01-01

Even if the performance of a given ventilator has been evaluated in the laboratory under very well controlled conditions, inappropriate maintenance and lack of long-term stability and accuracy of the ventilator sensors may lead to ventilation errors in actual clinical practice. The aim of this study was to evaluate the actual performances of ventilators during clinical routines. A resistance (7.69 cmH(2)O/L/s) - elastance (100 mL/cmH(2)O) test lung equipped with pressure, flow, and oxygen concentration sensors was connected to the Y-piece of all the mechanical ventilators available for patients in four intensive care units (ICUs; n = 66). Ventilators were set to volume-controlled ventilation with tidal volume = 600 mL, respiratory rate = 20 breaths/minute, positive end-expiratory pressure (PEEP) = 8 cmH(2)O, and oxygen fraction = 0.5. The signals from the sensors were recorded to compute the ventilation parameters. The average ± standard deviation and range (min-max) of the ventilatory parameters were the following: inspired tidal volume = 607 ± 36 (530-723) mL, expired tidal volume = 608 ± 36 (530-728) mL, peak pressure = 20.8 ± 2.3 (17.2-25.9) cmH(2)O, respiratory rate = 20.09 ± 0.35 (19.5-21.6) breaths/minute, PEEP = 8.43 ± 0.57 (7.26-10.8) cmH(2)O, oxygen fraction = 0.49 ± 0.014 (0.41-0.53). The more error-prone parameters were the ones related to the measure of flow. In several cases, the actual delivered mechanical ventilation was considerably different from the set one, suggesting the need for improving quality control procedures for these machines.

Mild hypothermia attenuates changes in respiratory system mechanics and modifies cytokine concentration in bronchoalveolar lavage fluid during low lung volume ventilation.

PubMed

Dostál, P; Senkeřík, M; Pařízková, R; Bareš, D; Zivný, P; Zivná, H; Cerný, V

2010-01-01

Hypothermia was shown to attenuate ventilator-induced lung injury due to large tidal volumes. It is unclear if the protective effect of hypothermia is maintained under less injurious mechanical ventilation in animals without previous lung injury. Tracheostomized rats were randomly allocated to non-ventilated group (group C) or ventilated groups of normothermia (group N) and mild hypothermia (group H). After two hours of mechanical ventilation with inspiratory fraction of oxygen 1.0, respiratory rate 60 min(-1), tidal volume 10 ml x kg(-1), positive end-expiratory pressure (PEEP) 2 cm H2O or immediately after tracheostomy in non-ventilated animals inspiratory pressures were recorded, rats were sacrificed, pressure-volume (PV) curve of respiratory system constructed, bronchoalveolar lavage (BAL) fluid and aortic blood samples obtained. Group N animals exhibited a higher rise in peak inspiratory pressures in comparison to group H animals. Shift of the PV curve to right, higher total protein and interleukin-6 levels in BAL fluid were observed in normothermia animals in comparison with hypothermia animals and non-ventilated controls. Tumor necrosis factor-alpha was lower in the hypothermia group in comparison with normothermia and non-ventilated groups. Mild hypothermia attenuated changes in respiratory system mechanics and modified cytokine concentration in bronchoalveolar lavage fluid during low lung volume ventilation in animals without previous lung injury.

An object-oriented computational model to study cardiopulmonary hemodynamic interactions in humans.

PubMed

Ngo, Chuong; Dahlmanns, Stephan; Vollmer, Thomas; Misgeld, Berno; Leonhardt, Steffen

2018-06-01

This work introduces an object-oriented computational model to study cardiopulmonary interactions in humans. Modeling was performed in object-oriented programing language Matlab Simscape, where model components are connected with each other through physical connections. Constitutive and phenomenological equations of model elements are implemented based on their non-linear pressure-volume or pressure-flow relationship. The model includes more than 30 physiological compartments, which belong either to the cardiovascular or respiratory system. The model considers non-linear behaviors of veins, pulmonary capillaries, collapsible airways, alveoli, and the chest wall. Model parameters were derisved based on literature values. Model validation was performed by comparing simulation results with clinical and animal data reported in literature. The model is able to provide quantitative values of alveolar, pleural, interstitial, aortic and ventricular pressures, as well as heart and lung volumes during spontaneous breathing and mechanical ventilation. Results of baseline simulation demonstrate the consistency of the assigned parameters. Simulation results during mechanical ventilation with PEEP trials can be directly compared with animal and clinical data given in literature. Object-oriented programming languages can be used to model interconnected systems including model non-linearities. The model provides a useful tool to investigate cardiopulmonary activity during spontaneous breathing and mechanical ventilation. Copyright © 2018 Elsevier B.V. All rights reserved.

Demand controlled ventilating systems: Sensor market survey. Energy conservation in buildings and community systems programme, annex 18, December 1991

NASA Astrophysics Data System (ADS)

Raatschen, W.; Sjoegren, M.

The subject of indoor and outdoor air quality has generated a great deal of attention in many countries. Areas of concern include outgassing of building materials as well as occupant-generated pollutants such as carbon dioxide, moisture, and odors. Progress has also been made towards addressing issues relating to the air tightness of the building envelope. Indoor air quality studies indicate that better control of supply flow rates as well as the air distribution pattern within buildings are necessary. One method of maintaining good indoor air quality without extensive energy consumption is to control the ventilation rate according to the needs and demands of the occupants, or to preserve the building envelope. This is accomplished through the use of demand controlled ventilating (DCV) systems. The specific objective of Annex 18 is to develop guidelines for demand controlled ventilating systems based on state of the art analyses, case studies on ventilation effectiveness, and proposed ventilation rates for different users in domestic, office, and school buildings.

Equation Discovery for Model Identification in Respiratory Mechanics of the Mechanically Ventilated Human Lung

NASA Astrophysics Data System (ADS)

Ganzert, Steven; Guttmann, Josef; Steinmann, Daniel; Kramer, Stefan

Lung protective ventilation strategies reduce the risk of ventilator associated lung injury. To develop such strategies, knowledge about mechanical properties of the mechanically ventilated human lung is essential. This study was designed to develop an equation discovery system to identify mathematical models of the respiratory system in time-series data obtained from mechanically ventilated patients. Two techniques were combined: (i) the usage of declarative bias to reduce search space complexity and inherently providing the processing of background knowledge. (ii) A newly developed heuristic for traversing the hypothesis space with a greedy, randomized strategy analogical to the GSAT algorithm. In 96.8% of all runs the applied equation discovery system was capable to detect the well-established equation of motion model of the respiratory system in the provided data. We see the potential of this semi-automatic approach to detect more complex mathematical descriptions of the respiratory system from respiratory data.

46 CFR 194.20-5 - Ventilation.

Code of Federal Regulations, 2010 CFR

2010-10-01

... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND... Ventilation. (a) Chemical storerooms shall be equipped with a power ventilation system of exhaust type. The... based upon the volume of the compartment. (1) Power ventilation units shall have nonsparking impellers...

Outcome-based ventilation: A framework for assessing performance, health, and energy impacts to inform office building ventilation decisions.

PubMed

Rackes, A; Ben-David, T; Waring, M S

2018-07-01

This article presents an outcome-based ventilation (OBV) framework, which combines competing ventilation impacts into a monetized loss function ($/occ/h) used to inform ventilation rate decisions. The OBV framework, developed for U.S. offices, considers six outcomes of increasing ventilation: profitable outcomes realized from improvements in occupant work performance and sick leave absenteeism; health outcomes from occupant exposure to outdoor fine particles and ozone; and energy outcomes from electricity and natural gas usage. We used the literature to set low, medium, and high reference values for OBV loss function parameters, and evaluated the framework and outcome-based ventilation rates using a simulated U.S. office stock dataset and a case study in New York City. With parameters for all outcomes set at medium values derived from literature-based central estimates, higher ventilation rates' profitable benefits dominated negative health and energy impacts, and the OBV framework suggested ventilation should be ≥45 L/s/occ, much higher than the baseline ~8.5 L/s/occ rate prescribed by ASHRAE 62.1. Only when combining very low parameter estimates for profitable impacts with very high ones for health and energy impacts were all outcomes on the same order. Even then, however, outcome-based ventilation rates were often twice the baseline rate or more. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Protective garment ventilation system

NASA Technical Reports Server (NTRS)

Lang, R. (Inventor)

1970-01-01

A method and apparatus for ventilating a protective garment, space suit system, and/or pressure suits to maintain a comfortable and nontoxic atmosphere within is described. The direction of flow of a ventilating and purging gas in portions of the garment may be reversed in order to compensate for changes in environment and activity of the wearer. The entire flow of the ventilating gas can also be directed first to the helmet associated with the garment.

Prediction and outcomes of impossible mask ventilation: a review of 50,000 anesthetics.

PubMed

Kheterpal, Sachin; Martin, Lizabeth; Shanks, Amy M; Tremper, Kevin K

2009-04-01

There are no existing data regarding risk factors for impossible mask ventilation and limited data regarding its incidence. The authors sought to determine the incidence, predictors, and outcomes associated with impossible mask ventilation. The authors performed an observational study over a 4-yr period. For each adult patient undergoing a general anesthetic, preoperative patient characteristics, detailed airway physical exam, and airway outcome data were collected. The primary outcome was impossible mask ventilation defined as the inability to exchange air during bag-mask ventilation attempts, despite multiple providers, airway adjuvants, or neuromuscular blockade. Secondary outcomes included the final, definitive airway management technique and direct laryngoscopy view. The incidence of impossible mask ventilation was calculated. Independent (P < 0.05) predictors of impossible mask ventilation were identified by performing a logistic regression full model fit. Over a 4-yr period from 2004 to 2008, 53,041 attempts at mask ventilation were recorded. A total of 77 cases of impossible mask ventilation (0.15%) were observed. Neck radiation changes, male sex, sleep apnea, Mallampati III or IV, and presence of beard were identified as independent predictors. The receiver-operating-characteristic area under the curve for this model was 0.80 +/- 0.03. Nineteen impossible mask ventilation patients (25%) also demonstrated difficult intubation, with 15 being intubated successfully. Twelve patients required an alternative intubation technique, including two surgical airways and two patients who were awakened and underwent successful fiberoptic intubation. Impossible mask ventilation is an infrequent airway event that is associated with difficult intubation. Neck radiation changes represent the most significant clinical predictor of impossible mask ventilation in the patient dataset.

Carbon Dioxide Detection and Indoor Air Quality Control.

PubMed

Bonino, Steve

2016-04-01

When building ventilation is reduced, energy is saved because it is not necessary to heat or cool as much outside air. Reduced ventilation can result in higher levels of carbon dioxide, which may cause building occupants to experience symptoms. Heating or cooling for ventilation air can be enhanced by a DCV system, which can save energy while providing a comfortable environment. Carbon dioxide concentrations within a building are often used to indicate whether adequate fresh air is being supplied to the building. These DCV systems use carbon dioxide sensors in each space or in the return air and adjust the ventilation based on carbon dioxide concentration; the higher the concentration, the more people occupy the space relative to the ventilation rate. With a carbon dioxide sensor DCV system, the fresh air ventilation rate varies based on the number ofpeople in the space, saving energy while maintaining a safe and comfortable environment.

A new system for continuous and remote monitoring of patients receiving home mechanical ventilation

NASA Astrophysics Data System (ADS)

Battista, L.

2016-09-01

Home mechanical ventilation is the treatment of patients with respiratory failure or insufficiency by means of a mechanical ventilator at a patient's home. In order to allow remote patient monitoring, several tele-monitoring systems have been introduced in the last few years. However, most of them usually do not allow real-time services, as they have their own proprietary communication protocol implemented and some ventilation parameters are not always measured. Moreover, they monitor only some breaths during the whole day, despite the fact that a patient's respiratory state may change continuously during the day. In order to reduce the above drawbacks, this work reports the development of a novel remote monitoring system for long-term, home-based ventilation therapy; the proposed system allows for continuous monitoring of the main physical quantities involved during home-care ventilation (e.g., differential pressure, volume, and air flow rate) and is developed in order to allow observations of different remote therapy units located in different places of a city, region, or country. The developed remote patient monitoring system is able to detect various clinical events (e.g., events of tube disconnection and sleep apnea events) and has been successfully tested by means of experimental tests carried out with pulmonary ventilators typically used to support sick patients.

A new system for continuous and remote monitoring of patients receiving home mechanical ventilation.

PubMed

Battista, L

2016-09-01

Home mechanical ventilation is the treatment of patients with respiratory failure or insufficiency by means of a mechanical ventilator at a patient's home. In order to allow remote patient monitoring, several tele-monitoring systems have been introduced in the last few years. However, most of them usually do not allow real-time services, as they have their own proprietary communication protocol implemented and some ventilation parameters are not always measured. Moreover, they monitor only some breaths during the whole day, despite the fact that a patient's respiratory state may change continuously during the day. In order to reduce the above drawbacks, this work reports the development of a novel remote monitoring system for long-term, home-based ventilation therapy; the proposed system allows for continuous monitoring of the main physical quantities involved during home-care ventilation (e.g., differential pressure, volume, and air flow rate) and is developed in order to allow observations of different remote therapy units located in different places of a city, region, or country. The developed remote patient monitoring system is able to detect various clinical events (e.g., events of tube disconnection and sleep apnea events) and has been successfully tested by means of experimental tests carried out with pulmonary ventilators typically used to support sick patients.

Comfort parameters - Ventilation of a subway wagon

NASA Astrophysics Data System (ADS)

Petr, Pavlíček; Ladislav, Tříska

2017-09-01

Research and development of a ventilation system is being carried out as a part of project TA04030774 of the Technology Agency of the Czech Republic. Name of the project is "Research and Development of Mass-optimized Components for Rail Vehicles". Problems being solved are development and testing of a new concept for ventilation systems for public transport vehicles. The main improvements should be a reduction of the mass of the whole system, easy installation and reduction of the noise of the ventilation system. This article is focused on the comfort parameters in a subway wagon (measurement and evaluation carried out on a function sample in accordance with the regulations). The input to the project is a ventilator hybrid casing for a subway wagon, which was manufactured and tested during the Ministry of Industry and Trade project TIP FR-TI3/449.

Experimental system for the control of surgically induced infections

NASA Technical Reports Server (NTRS)

Tevebaugh, M. D.

1971-01-01

The development tests to be performed on the experimental system are described in detail. The test equipment, conditions, and procedures are given. The portable clean room tests include assembly, collapsability, portability, and storage; laminar flow rate; static pressure; air flow pattern; and electrostatic buildup. The other tests are on the ventilation system, human factors evaluation, electrical subsystem, and material compatibility.

Creating high performance buildings: Lower energy, better comfort

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brager, Gail; Arens, Edward

2015-03-30

Buildings play a critical role in the challenge of mitigating and adapting to climate change. It is estimated that buildings contribute 39% of the total U.S. greenhouse gas (GHG) emissions [1] primarily due to their operational energy use, and about 80% of this building energy use is for heating, cooling, ventilating, and lighting. An important premise of this paper is about the connection between energy and comfort. They are inseparable when one talks about high performance buildings. Worldwide data suggests that we are significantly overcooling buildings in the summer, resulting in increased energy use and problems with thermal comfort. Inmore » contrast, in naturally ventilated buildings without mechanical cooling, people are comfortable in much warmer temperatures due to shifting expectations and preferences as a result of occupants having a greater degree of personal control over their thermal environment; they have also become more accustomed to variable conditions that closely reflect the natural rhythms of outdoor climate patterns. This has resulted in an adaptive comfort zone that offers significant potential for encouraging naturally ventilated buildings to improve both energy use and comfort. Research on other forms for providing individualized control through low-energy personal comfort systems (desktop fans, foot warmed, and heated and cooled chairs) have also demonstrated enormous potential for improving both energy and comfort performance. Studies have demonstrated high levels of comfort with these systems while ambient temperatures ranged from 64–84°F. Energy and indoor environmental quality are inextricably linked, and must both be important goals of a high performance building.« less

40 CFR 63.8230 - By what date must I conduct performance tests or other initial compliance demonstrations?

Code of Federal Regulations, 2010 CFR

2010-07-01

... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Initial Compliance... § 63.8190(a)(2) for by-product hydrogen streams and end box ventilation system vents and the applicable...

40 CFR 63.8230 - By what date must I conduct performance tests or other initial compliance demonstrations?

Code of Federal Regulations, 2011 CFR

2011-07-01

... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Initial Compliance... § 63.8190(a)(2) for by-product hydrogen streams and end box ventilation system vents and the applicable...

40 CFR 63.8230 - By what date must I conduct performance tests or other initial compliance demonstrations?

Code of Federal Regulations, 2013 CFR

2013-07-01

... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Initial Compliance... § 63.8190(a)(2) for by-product hydrogen streams and end box ventilation system vents and the applicable...

40 CFR 63.8230 - By what date must I conduct performance tests or other initial compliance demonstrations?

Code of Federal Regulations, 2014 CFR

2014-07-01

... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Initial Compliance... § 63.8190(a)(2) for by-product hydrogen streams and end box ventilation system vents and the applicable...

40 CFR 63.8230 - By what date must I conduct performance tests or other initial compliance demonstrations?

Code of Federal Regulations, 2012 CFR

2012-07-01

... Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Initial Compliance Requirements § 63.8230...(a)(2) for by-product hydrogen streams and end box ventilation system vents and the applicable...

40 CFR 98.323 - Calculating GHG emissions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... systems (metric tons CH4). CH4V = Quarterly CH4 liberated from each ventilation monitoring point (metric... vent holes are collected, you must calculate the quarterly CH4 liberated from the ventilation system... CH4 liberated from a ventilation monitoring point (metric tons CH4). V = Volumetric flow rate for the...

24 CFR 3280.710 - Venting, ventilation and combustion air.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Venting, ventilation and combustion... Fuel Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting as required by... appliance listing and the appliance manufacturer's instructions. (b) Venting and combustion air systems...

24 CFR 3280.710 - Venting, ventilation and combustion air.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Venting, ventilation and combustion... Fuel Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting as required by... appliance listing and the appliance manufacturer's instructions. (b) Venting and combustion air systems...

24 CFR 3280.710 - Venting, ventilation and combustion air.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 24 Housing and Urban Development 5 2012-04-01 2012-04-01 false Venting, ventilation and combustion... Fuel Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting as required by... appliance listing and the appliance manufacturer's instructions. (b) Venting and combustion air systems...

24 CFR 3280.710 - Venting, ventilation and combustion air.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Venting, ventilation and combustion... Fuel Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting as required by... appliance listing and the appliance manufacturer's instructions. (b) Venting and combustion air systems...

24 CFR 3280.710 - Venting, ventilation and combustion air.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Venting, ventilation and combustion... Fuel Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting as required by... appliance listing and the appliance manufacturer's instructions. (b) Venting and combustion air systems...

A novel preterm respiratory mechanics active simulator to test the performances of neonatal pulmonary ventilators

NASA Astrophysics Data System (ADS)

Cappa, Paolo; Sciuto, Salvatore Andrea; Silvestri, Sergio

2002-06-01

A patient active simulator is proposed which is capable of reproducing values of the parameters of pulmonary mechanics of healthy newborns and preterm pathological infants. The implemented prototype is able to: (a) let the operator choose the respiratory pattern, times of apnea, episodes of cough, sobs, etc., (b) continuously regulate and control the parameters characterizing the pulmonary system; and, finally, (c) reproduce the attempt of breathing of a preterm infant. Taking into account both the limitation due to the chosen application field and the preliminary autocalibration phase automatically carried out by the proposed device, accuracy and reliability on the order of 1% is estimated. The previously indicated value has to be considered satisfactory in light of the field of application and the small values of the simulated parameters. Finally, the achieved metrological characteristics allow the described neonatal simulator to be adopted as a reference device to test performances of neonatal ventilators and, more specifically, to measure the time elapsed between the occurrence of a potentially dangerous condition to the patient and the activation of the corresponding alarm of the tested ventilator.

Comparison of Ventilation and Cardiac Compressions When Utilizing the Impact Model 730 Automatic Transport Ventilator Versus a Conventional Bag Valve With a Facemask in a Model of Adult Cadiopulmonary Arrest

DTIC Science & Technology

2005-10-25

Chest compression , Ventilation 2P251107 256Page 2 1. Introduction During the initial stages of cardiopulmonary resuscitation ( CPR ), ventilation is...a metronome to facilitate chest compression timing. Twenty-eight nurses alternated performing 4 minutes of CPR using the BVM or Impact 730 to deliver... Chest compression and ventilation rates during cardiopulmonary resuscitation : the effects of audible tone guidance. Academic Emergency Medicine

Prevalence and test characteristics of national health safety network ventilator-associated events.

PubMed

Lilly, Craig M; Landry, Karen E; Sood, Rahul N; Dunnington, Cheryl H; Ellison, Richard T; Bagley, Peter H; Baker, Stephen P; Cody, Shawn; Irwin, Richard S

2014-09-01

The primary aim of the study was to measure the test characteristics of the National Health Safety Network ventilator-associated event/ventilator-associated condition constructs for detecting ventilator-associated pneumonia. Its secondary aims were to report the clinical features of patients with National Health Safety Network ventilator-associated event/ventilator-associated condition, measure costs of surveillance, and its susceptibility to manipulation. Prospective cohort study. Two inpatient campuses of an academic medical center. Eight thousand four hundred eight mechanically ventilated adults discharged from an ICU. None. The National Health Safety Network ventilator-associated event/ventilator-associated condition constructs detected less than a third of ventilator-associated pneumonia cases with a sensitivity of 0.325 and a positive predictive value of 0.07. Most National Health Safety Network ventilator-associated event/ventilator-associated condition cases (93%) did not have ventilator-associated pneumonia or other hospital-acquired complications; 71% met the definition for acute respiratory distress syndrome. Similarly, most patients with National Health Safety Network probable ventilator-associated pneumonia did not have ventilator-associated pneumonia because radiographic criteria were not met. National Health Safety Network ventilator-associated event/ventilator-associated condition rates were reduced 93% by an unsophisticated manipulation of ventilator management protocols. The National Health Safety Network ventilator-associated event/ventilator-associated condition constructs failed to detect many patients who had ventilator-associated pneumonia, detected many cases that did not have a hospital complication, and were susceptible to manipulation. National Health Safety Network ventilator-associated event/ventilator-associated condition surveillance did not perform as well as ventilator-associated pneumonia surveillance and had several undesirable characteristics.

A program for sustained improvement in preventing ventilator associated pneumonia in an intensive care setting

PubMed Central

2012-01-01

Background Ventilator-associated pneumonia (VAP) is a common infection in the intensive care unit (ICU) and associated with a high mortality. Methods A quasi-experimental study was conducted in a medical-surgical ICU. Multiple interventions to optimize VAP prevention were performed from October 2008 to December 2010. All of these processes, including the Institute for Healthcare Improvement’s (IHI) ventilator bundle plus oral decontamination with chlorhexidine and continuous aspiration of subglottic secretions (CASS), were adopted for patients undergoing mechanical ventilation. Results We evaluated a total of 21,984 patient-days, and a total of 6,052 ventilator-days (ventilator utilization rate of 0.27). We found VAP rates of 1.3 and 2.0 per 1,000 ventilator days respectively in 2009 and 2010, achieving zero incidence of VAP several times during 12 months, whenever VAP bundle compliance was over 90%. Conclusion These results suggest that it is possible to reduce VAP rates to near zero and sustain these rates, but it requires a complex process involving multiple performance measures and interventions that must be permanently monitored. PMID:23020101

A program for sustained improvement in preventing ventilator associated pneumonia in an intensive care setting.

PubMed

Caserta, Raquel A; Marra, Alexandre R; Durão, Marcelino S; Silva, Cláudia Vallone; Pavao dos Santos, Oscar Fernando; Neves, Henrique Sutton de Sousa; Edmond, Michael B; Timenetsky, Karina Tavares

2012-09-29

Ventilator-associated pneumonia (VAP) is a common infection in the intensive care unit (ICU) and associated with a high mortality. A quasi-experimental study was conducted in a medical-surgical ICU. Multiple interventions to optimize VAP prevention were performed from October 2008 to December 2010. All of these processes, including the Institute for Healthcare Improvement's (IHI) ventilator bundle plus oral decontamination with chlorhexidine and continuous aspiration of subglottic secretions (CASS), were adopted for patients undergoing mechanical ventilation. We evaluated a total of 21,984 patient-days, and a total of 6,052 ventilator-days (ventilator utilization rate of 0.27). We found VAP rates of 1.3 and 2.0 per 1,000 ventilator days respectively in 2009 and 2010, achieving zero incidence of VAP several times during 12 months, whenever VAP bundle compliance was over 90%. These results suggest that it is possible to reduce VAP rates to near zero and sustain these rates, but it requires a complex process involving multiple performance measures and interventions that must be permanently monitored.

New ocular movement detector system as a communication tool in ventilator-assisted Werdnig-Hoffmann disease.

PubMed

Kubota, M; Sakakihara, Y; Uchiyama, Y; Nara, A; Nagata, T; Nitta, H; Ishimoto, K; Oka, A; Horio, K; Yanagisawa, M

2000-01-01

A non-contact communication system was developed for a ventilator-assisted patient with Werdnig-Hoffmann disease who had lost all voluntary movements except for those of the eye. The system detects the extraocular movements and converts them to either a 'yes' signal (produced by one lateral eyeball movement) or a 'no' signal (produced by two successive lateral eyeball movements) using a video camera placed outside the patient's visual field. The patient is thus able to concentrate on performing a task without any intrusion from the detection system. Once the setting conditions of the device have been selected, there is no need for any resetting, as the patient is unable to move his body. In addition to playing television games, the child can use the device to select television channels, compose music, and learn written Japanese and Chinese characters. This seems to broaden the patient's daily world and promote mental development.

Performance simulation for the design of solar heating and cooling systems

NASA Technical Reports Server (NTRS)

Mccormick, P. O.

1975-01-01

Suitable approaches for evaluating the performance and the cost of a solar heating and cooling system are considered, taking into account the value of a computer simulation concerning the entire system in connection with the large number of parameters involved. Operational relations concerning the collector efficiency in the case of a new improved collector and a reference collector are presented in a graph. Total costs for solar and conventional heating, ventilation, and air conditioning systems as a function of time are shown in another graph.

Evaluation of Mechanical Ventilator Use with Liquid Oxygen Systems

DTIC Science & Technology

2017-02-22

patients using long-term liquid oxygen differ from those on traditional treatment with oxygen concentrators and/or compressed gas cylinders? A...AFRL-SA-WP-SR-2017-0006 Evaluation of Mechanical Ventilator Use with Liquid Oxygen Systems Thomas Blakeman, MSc, RRT; Dario...To) August 2014 – September 2016 4. TITLE AND SUBTITLE Evaluation of Mechanical Ventilator Use with Liquid Oxygen Systems 5a. CONTRACT NUMBER

Energy Use Consequences of Ventilating a Net-Zero Energy House

PubMed Central

Ng, Lisa C.; Payne, W. Vance

2016-01-01

A Net-Zero Energy Residential Test Facility (NZERTF) has been constructed at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland to demonstrate that a home similar in size, aesthetics, and amenities to those in the surrounding communities can achieve net-zero energy use over the course of a year while meeting the average electricity and water use needs of a family of four in the United States. The facility incorporates renewable energy and energy efficient technologies, including an air-to-air heat pump system, a solar photovoltaic system, a solar thermal domestic hot water system, and a heat recovery ventilation system sized to meet American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) Standard 62.2-2010 ventilation requirements. The largest energy end use within the home was space conditioning, which included heat loss through the building envelope, ventilation air supplied by the heat recovery ventilator (HRV), and internal loads. While HRVs are often described as being able to save energy when compared to ventilating without heat recovery, there have been no studies using a full year of measured data that determine the thermal load and energy impacts of HRV-based ventilation on the central heating and cooling system. Over the course of a year, continuous operation of the HRV at the NZERTF resulted in an annual savings of 7 % in heat pump energy use compared with the hypothetical case of ventilating without heat recovery. The heat pump electrical use varied from an increase of 5 % in the cooling months to 36 % savings in the heating months compared with ventilation without heat recovery. The increase in the cooling months occurred when the outdoor temperature was lower than the indoor temperature, during which the availability of an economizer mode would have been beneficial. Nevertheless, the fan energy required to operate the selected HRV at the NZERTF paid for itself in the heat pump energy saved compared with ventilation without heat recovery. PMID:26903776

Energy Use Consequences of Ventilating a Net-Zero Energy House.

PubMed

Ng, Lisa C; Payne, W Vance

2016-03-05

A Net-Zero Energy Residential Test Facility (NZERTF) has been constructed at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland to demonstrate that a home similar in size, aesthetics, and amenities to those in the surrounding communities can achieve net-zero energy use over the course of a year while meeting the average electricity and water use needs of a family of four in the United States. The facility incorporates renewable energy and energy efficient technologies, including an air-to-air heat pump system, a solar photovoltaic system, a solar thermal domestic hot water system, and a heat recovery ventilation system sized to meet American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) Standard 62.2-2010 ventilation requirements. The largest energy end use within the home was space conditioning, which included heat loss through the building envelope, ventilation air supplied by the heat recovery ventilator (HRV), and internal loads. While HRVs are often described as being able to save energy when compared to ventilating without heat recovery, there have been no studies using a full year of measured data that determine the thermal load and energy impacts of HRV-based ventilation on the central heating and cooling system. Over the course of a year, continuous operation of the HRV at the NZERTF resulted in an annual savings of 7 % in heat pump energy use compared with the hypothetical case of ventilating without heat recovery. The heat pump electrical use varied from an increase of 5 % in the cooling months to 36 % savings in the heating months compared with ventilation without heat recovery. The increase in the cooling months occurred when the outdoor temperature was lower than the indoor temperature, during which the availability of an economizer mode would have been beneficial. Nevertheless, the fan energy required to operate the selected HRV at the NZERTF paid for itself in the heat pump energy saved compared with ventilation without heat recovery.

46 CFR 127.260 - Ventilation for accommodations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Ventilation for accommodations. 127.260 Section 127.260... ARRANGEMENTS Particular Construction and Arrangements § 127.260 Ventilation for accommodations. (a) Each... vessel of 100 or more gross tons must be provided with a mechanical ventilation system unless the...

Effect of residential air-to-air heat and moisture exchangers on indoor humidity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barringer, C.G.; McGugan, C.A.

1989-01-01

A project was undertaken to develop guidelines for the selection of residential heat and moisture recovery ventilation systems (HRVs) in order to maintain an acceptable indoor humidity for various climatic conditions. These guidelines were developed from reviews on ventilation requirements, HRV performance specifications, and from computer modeling. Space conditions within three house/occupancy models for several types of HRV were simulated for three climatic conditions (Lake Charles, LA; Seattle, WA; and Winnipeg, MB) in order to determine the impact of the HRVs on indoor relative humidity and space-conditioning loads. Results show that when reduction of cooling cost is the main consideration,more » exchangers with moisture recovery are preferable to sensible HRVs. For reduction of heating costs, moisture recovery should be done for ventilation rates greater than about 15 L/s and average winter temperatures less than about (minus) 10{degrees}C if internal moisture generation rates are low. For houses with higher ventilation rates and colder average winter temperatures, exchangers with moisture recovery should be used.« less

An intelligent FFR with a self-adjustable ventilation fan.

PubMed

Zhou, Song; Li, Hui; Shen, Shengnan; Li, Siyu; Wang, Wei; Zhang, Xiaotie; Yang, James

2017-11-01

This article presents an intelligent Filtering Facepiece Respirator (FFR) with a self-adjustable ventilation fan for improved comfort. The ventilation fan with an intelligent control aims to reduce temperature, relative humidity, and CO 2 concentrations inside the facepiece. Compared with a previous version of the FFR, the advantage of this new FFR is the intelligent control of the fan's rotation speed based on the change in temperature and relative humidity in the FFR dead space. The design of the control system utilizes an 8-bit, ultra-low power STC15W404AS microcontroller (HongJin technology, Shenzhen, China), and adopts a high-precision AM2320 device (AoSong electronic, Guangzhou, China) as temperature and relative humidity sensor so that control of temperature and relative humidity is realized in real time within the FFR dead space. The ventilation fan is intelligently driven and runs on a rechargeable lithium battery with a power-save mode that provides a correspondingly longer operational time. Meanwhile, the design is simplistic. Two experiments were performed to determine the best location to place the fan.

A perfluorochemical loss/restoration (L/R) system for tidal liquid ventilation.

PubMed

Libros, R; Philips, C M; Wolfson, M R; Shaffer, T H

2000-01-01

Tidal liquid ventilation is the transport of dissolved respiratory gases via volume exchange of perfluorochemical (PFC) liquid to and from the PFC-filled lung. All gas-liquid surface tension is eliminated, increasing compliance and providing lung protection due to lower inflation pressures. Tidal liquid ventilation is achieved by cycling fluid from a reservoir to and from the lung by a ventilator. Current approaches are microprocessor-based with feedback control. During inspiration, warmed oxygenated PFC liquid is pumped from a fluid reservoir/gas exchanger into the lung. PFC fluid is conserved by condensing (60-80% efficiency) vapor in the expired gas. A feedback-control system was developed to automatically replace PFC lost due to condenser inefficiency. This loss/restoration (L/R) system consists of a PFC-vapor thermal detector (+/- 2.5%), pneumatics, amplifiers, a gas flow detector (+/- 1%), a PFC pump (+/- 5%), and a controller. Gravimetric studies of perflubron loss from a flask due to evaporation were compared with experimental L/R results and found to be within +/- 1.4%. In addition, when L/R studies were conducted with a previously reported liquid ventilation system over a four-hour period, the L/R system maintained system perflubron volume to within +/- 1% of prime volume and 11.5% of replacement volume, and the difference between experimental PFC loss and that of the L/R system was 1.8 mL/hr. These studies suggest that the PFC L/R system may have significant economic (appropriate dosing for PFC loss) as well as physiologic (maintenance of PFC inventory in the lungs and liquid ventilator) impact on liquid ventilation procedures.

Performance of particulate containment at nanotechnology workplaces

NASA Astrophysics Data System (ADS)

Lo, Li-Ming; Tsai, Candace S.-J.; Dunn, Kevin H.; Hammond, Duane; Marlow, David; Topmiller, Jennifer; Ellenbecker, Michael

2015-11-01

The evaluation of engineering controls for the production or use of carbon nanotubes (CNTs) was investigated at two facilities. These control assessments are necessary to evaluate the current status of control performance and to develop proper control strategies for these workplaces. The control systems evaluated in these studies included ventilated enclosures, exterior hoods, and exhaust filtration systems. Activity-based monitoring with direct-reading instruments and filter sampling for microscopy analysis were used to evaluate the effectiveness of control measures at study sites. Our study results showed that weighing CNTs inside the biological safety cabinet can have a 37 % reduction on the particle concentration in the worker's breathing zone, and produce a 42 % lower area concentration outside the enclosure. The ventilated enclosures used to reduce fugitive emissions from the production furnaces exhibited good containment characteristics when closed, but they failed to contain emissions effectively when opened during product removal/harvesting. The exhaust filtration systems employed for exhausting these ventilated enclosures did not provide promised collection efficiencies for removing engineered nanomaterials from furnace exhaust. The exterior hoods were found to be a challenge for controlling emissions from machining nanocomposites: the downdraft hood effectively contained and removed particles released from the manual cutting process, but using the canopy hood for powered cutting of nanocomposites created 15-20 % higher ultrafine (<500 nm) particle concentrations at the source and at the worker's breathing zone. The microscopy analysis showed that CNTs can only be found at production sources but not at the worker breathing zones during the tasks monitored.

Evaluating Humidity Recovery Efficiency of Currently Available Heat and Moisture Exchangers: A Respiratory System Model Study

PubMed Central

Lucato, Jeanette Janaina Jaber; Adams, Alexander Bernard; Souza, Rogério; Torquato, Jamili Anbar; Carvalho, Carlos Roberto Ribeiro; Marini, John J

2009-01-01

OBJECTIVES: To evaluate and compare the efficiency of humidification in available heat and moisture exchanger models under conditions of varying tidal volume, respiratory rate, and flow rate. INTRODUCTION: Inspired gases are routinely preconditioned by heat and moisture exchangers to provide a heat and water content similar to that provided normally by the nose and upper airways. The absolute humidity of air retrieved from and returned to the ventilated patient is an important measurable outcome of the heat and moisture exchangers’ humidifying performance. METHODS: Eight different heat and moisture exchangers were studied using a respiratory system analog. The system included a heated chamber (acrylic glass, maintained at 37°C), a preserved swine lung, a hygrometer, circuitry and a ventilator. Humidity and temperature levels were measured using eight distinct interposed heat and moisture exchangers given different tidal volumes, respiratory frequencies and flow-rate conditions. Recovery of absolute humidity (%RAH) was calculated for each setting. RESULTS: Increasing tidal volumes led to a reduction in %RAH for all heat and moisture exchangers while no significant effect was demonstrated in the context of varying respiratory rate or inspiratory flow. CONCLUSIONS: Our data indicate that heat and moisture exchangers are more efficient when used with low tidal volume ventilation. The roles of flow and respiratory rate were of lesser importance, suggesting that their adjustment has a less significant effect on the performance of heat and moisture exchangers. PMID:19578664

EVALUATION OF VENTILATION PERFORMANCE FOR INDOOR SPACE

EPA Science Inventory

The paper discusses a personal-computer-based application of computational fluid dynamics that can be used to determine the turbulent flow field and time-dependent/steady-state contaminant concentration distributions within isothermal indoor space. (NOTE: Ventilation performance ...

Feasibility of the capnogram to monitor ventilation rate during cardiopulmonary resuscitation.

PubMed

Aramendi, Elisabete; Elola, Andoni; Alonso, Erik; Irusta, Unai; Daya, Mohamud; Russell, James K; Hubner, Pia; Sterz, Fritz

2017-01-01

The rates of chest compressions (CCs) and ventilations are both important metrics to monitor the quality of cardiopulmonary resuscitation (CPR). Capnography permits monitoring ventilation, but the CCs provided during CPR corrupt the capnogram and compromise the accuracy of automatic ventilation detectors. The aim of this study was to evaluate the feasibility of an automatic algorithm based on the capnogram to detect ventilations and provide feedback on ventilation rate during CPR, specifically addressing intervals where CCs are delivered. The dataset used to develop and test the algorithm contained in-hospital and out-of-hospital cardiac arrest episodes. The method relies on adaptive thresholding to detect ventilations in the first derivative of the capnogram. The performance of the detector was reported in terms of sensitivity (SE) and Positive Predictive Value (PPV). The overall performance was reported in terms of the rate error and errors in the hyperventilation alarms. Results were given separately for the intervals with CCs. A total of 83 episodes were considered, resulting in 4880min and 46,740 ventilations (8741 during CCs). The method showed an overall SE/PPV above 99% and 97% respectively, even in intervals with CCs. The error for the ventilation rate was below 1.8min -1 in any group, and >99% of the ventilation alarms were correctly detected. A method to provide accurate feedback on ventilation rate using only the capnogram is proposed. Its accuracy was proven even in intervals where canpography signal was severely corrupted by CCs. This algorithm could be integrated into monitor/defibrillators to provide reliable feedback on ventilation rate during CPR. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Comparison between conventional protective mechanical ventilation and high-frequency oscillatory ventilation associated with the prone position.

PubMed

Fioretto, José Roberto; Klefens, Susiane Oliveira; Pires, Rafaelle Fernandes; Kurokawa, Cilmery Suemi; Carpi, Mario Ferreira; Bonatto, Rossano César; Moraes, Marcos Aurélio; Ronchi, Carlos Fernando

2017-01-01

To compare the effects of high-frequency oscillatory ventilation and conventional protective mechanical ventilation associated with the prone position on oxygenation, histology and pulmonary oxidative damage in an experimental model of acute lung injury. Forty-five rabbits with tracheostomy and vascular access were underwent mechanical ventilation. Acute lung injury was induced by tracheal infusion of warm saline. Three experimental groups were formed: healthy animals + conventional protective mechanical ventilation, supine position (Control Group; n = 15); animals with acute lung injury + conventional protective mechanical ventilation, prone position (CMVG; n = 15); and animals with acute lung injury + high-frequency oscillatory ventilation, prone position (HFOG; n = 15). Ten minutes after the beginning of the specific ventilation of each group, arterial gasometry was collected, with this timepoint being called time zero, after which the animal was placed in prone position and remained in this position for 4 hours. Oxidative stress was evaluated by the total antioxidant performance assay. Pulmonary tissue injury was determined by histopathological score. The level of significance was 5%. Both groups with acute lung injury showed worsening of oxygenation after induction of injury compared with the Control Group. After 4 hours, there was a significant improvement in oxygenation in the HFOG group compared with CMVG. Analysis of total antioxidant performance in plasma showed greater protection in HFOG. HFOG had a lower histopathological lesion score in lung tissue than CMVG. High-frequency oscillatory ventilation, associated with prone position, improves oxygenation and attenuates oxidative damage and histopathological lung injury compared with conventional protective mechanical ventilation.

Comparison between conventional protective mechanical ventilation and high-frequency oscillatory ventilation associated with the prone position

PubMed Central

Fioretto, José Roberto; Klefens, Susiane Oliveira; Pires, Rafaelle Fernandes; Kurokawa, Cilmery Suemi; Carpi, Mario Ferreira; Bonatto, Rossano César; Moraes, Marcos Aurélio; Ronchi, Carlos Fernando

2017-01-01

Objective To compare the effects of high-frequency oscillatory ventilation and conventional protective mechanical ventilation associated with the prone position on oxygenation, histology and pulmonary oxidative damage in an experimental model of acute lung injury. Methods Forty-five rabbits with tracheostomy and vascular access were underwent mechanical ventilation. Acute lung injury was induced by tracheal infusion of warm saline. Three experimental groups were formed: healthy animals + conventional protective mechanical ventilation, supine position (Control Group; n = 15); animals with acute lung injury + conventional protective mechanical ventilation, prone position (CMVG; n = 15); and animals with acute lung injury + high-frequency oscillatory ventilation, prone position (HFOG; n = 15). Ten minutes after the beginning of the specific ventilation of each group, arterial gasometry was collected, with this timepoint being called time zero, after which the animal was placed in prone position and remained in this position for 4 hours. Oxidative stress was evaluated by the total antioxidant performance assay. Pulmonary tissue injury was determined by histopathological score. The level of significance was 5%. Results Both groups with acute lung injury showed worsening of oxygenation after induction of injury compared with the Control Group. After 4 hours, there was a significant improvement in oxygenation in the HFOG group compared with CMVG. Analysis of total antioxidant performance in plasma showed greater protection in HFOG. HFOG had a lower histopathological lesion score in lung tissue than CMVG. Conclusion High-frequency oscillatory ventilation, associated with prone position, improves oxygenation and attenuates oxidative damage and histopathological lung injury compared with conventional protective mechanical ventilation. PMID:29236845

Temperature of gas delivered from ventilators.

PubMed

Chikata, Yusuke; Onodera, Mutsuo; Imanaka, Hideaki; Nishimura, Masaji

2013-01-01

Although heated humidifiers (HHs) are the most efficient humidifying device for mechanical ventilation, some HHs do not provide sufficient humidification when the inlet temperature to the water chamber is high. Because portable and home-care ventilators use turbines, blowers, pistons, or compressors to inhale in ambient air, they may have higher gas temperature than ventilators with piping systems. We carried out a bench study to investigate the temperature of gas delivered from portable and home-care ventilators, including the effects of distance from ventilator outlet, fraction of inspiratory oxygen (FIO2), and minute volume (MV). We evaluated five ventilators equipped with turbine, blower, piston, or compressor system. Ambient air temperature was adjusted to 24°C ± 0.5°C, and ventilation was set at FIO2 0.21, 0.6, and 1.0, at MV 5 and 10 L/min. We analyzed gas temperature at 0, 40, 80, and 120 cm from ventilator outlet and altered ventilator settings. While temperature varied according to ventilators, the outlet gas temperature of ventilators became stable after, at the most, 5 h. Gas temperature was 34.3°C ± 3.9°C at the ventilator outlet, 29.5°C ± 2.2°C after 40 cm, 25.4°C ± 1.2°C after 80 cm and 25.1°C ± 1.2°C after 120 cm (P < 0.01). FIO2 and MV did not affect gas temperature. Gas delivered from portable and home-care ventilator was not too hot to induce heated humidifier malfunctioning. Gas soon declined when passing through the limb.

Supply Ventilation and Prevention of Carbon Monoxide (II) Ingress into Building Premises

NASA Astrophysics Data System (ADS)

Litvinova, N. A.

2017-11-01

The article contains the relationships of carbon monoxide (II) concentration versus height-above-ground near buildings derived based on results of studies. The results of studies are crucial in preventing external pollutants ingress into a ventilation system. Being generated by external emission sources, such as motor vehicles and city heating plants, carbon monoxide (II) enters the premises during operation of a supply ventilation system. Fresh air nomographic charts were drawn to select the height of a fresh air intake into the ventilation system. Nomographic charts take into account external sources. The selected emission sources are located at various levels above ground relative to the building. The recommendations allow designing supply ventilation taking into account the quality of ambient air through the whole building height.

Mechanical ventilation in disaster situations: a new paradigm using the AGILITIES Score System.

PubMed

Wilkens, Eric P; Klein, Gary M

2010-01-01

The failure of life-critical systems such as mechanical ventilators in the wake of a pandemic or a disaster may result in death, and therefore, state and federal government agencies must have precautions in place to ensure availability, reliability, and predictability through comprehensive preparedness and response plans. All 50 state emergency preparedness response plans were extensively examined for the attention given to the critically injured and ill patient population during a pandemic or mass casualty event. Public health authorities of each state were contacted as well. Nine of 51 state plans (17.6 percent) included a plan or committee for mechanical ventilation triage and management in a pandemic influenza event. All 51 state plans relied on the Centers for Disease Control and Prevention Flu Surge 2.0 spreadsheet to provide estimates for their influenza planning. In the absence of more specific guidance, the authors have developed and provided guidelines recommended for ventilator triage and the implementation of the AGILITIES Score in the event of a pandemic, mass casualty event, or other catastrophic disaster. The authors present and describe the AGILITIES Score Ventilator Triage System and provide related guidelines to be adopted uniformly by government agencies and hospitals. This scoring system and the set ofguidelines are to be used iA disaster settings, such as Hurricane Katrina, and are based on three key factors: relative health, duration of time on mechanical ventilation, and patients' use of resources during a disaster. For any event requiring large numbers of ventilators for patients, the United States is woefully unprepared. The deficiencies in this aspect of preparedness include (1) lack of accountability for physical ventilators, (2) lack of understanding with which healthcare professionals can safely operate these ventilators, (3) lack of understanding from where additional ventilator resources exist, and (4) a triage strategy to provide ventilator support to those patients with the greatest chances of survival.

Radiostethoscopes: an innovative solution for auscultation while wearing protective gear.

PubMed

Candiotti, Keith A; Rodriguez, Yiliam; Curia, Luciana; Saltzman, Bruce; Shekhter, Ilya; Rosen, Lisa; Birnbach, David J

2011-01-01

To demonstrate a radiostethoscope that could be modified and successfully used while wearing protective gear to solve the problem of auscultation in a hazardous material or infectious disease setting. This study was a randomized, prospective, and blinded investigation. The study was conducted at the University of Miami-Jackson Memorial Hospital Center for Patient Safety. Two blinded anesthesiologists using a radiostethoscope performed a total of 100 assessments (50 each) to evaluate endotracheal tube position on a human patient simulator (HPS). Each lung of the HPS was ventilated separately using a double lumen tube. Four ventilation patterns (ie, right lung ventilation only; left lung ventilation only; ventilation of both lungs; and an esophageal intubation or no breath sounds) were simulated. The ventilation pattern was determined randomly and participants were blinded. An Ambu-Bag was used for ventilation. An assistant moved the radiostethoscope to the right and left lung fields and then to the abdomen of the HPS while ventilating. Subjects had to identify the ventilation pattern after listening to all three locations. A third member of the research team collected responses. Each subject, who wore both types of respirator (positive and negative), performed a total of 25 trials. Participants later compared the two types of respirators and their ability to auscultate for breath sounds. Subjects were able to verify the correct ventilation pattern in all attempts (100 percent). Radiostethoscopes appear to provide a viable solution for the problem of patient auscultation while wearing protective gear.

Buildings operations and ETS exposure.

PubMed Central

Spengler, J D

1999-01-01

Mechanical systems are used in buildings to provide conditioned air, dissipate thermal loads, dilute contaminants, and maintain pressure differences. The characteristics of these systems and their operations h implications for the exposures of workers to environmental tobacco smoke (ETS) and for the control of these exposures. This review describes the general features of building ventilation systems and the efficacy of ventilation for controlling contaminant concentrations. Ventilation can reduce the concentration of ETS through dilution, but central heating, ventilating, and air conditioning (HVAC) can also move air throughout a building that has been contaminated by ETS. An understanding of HVAC systems is needed to develop models for exposures of workers to ETS. Images Figure 1 Figure 2 Figure 3 PMID:10375293

A Case Study in Market Transformation for Residential Energy Efficiency Programs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Building Technologies Office

This case study describes how the Midwest Energy Efficiency Alliance (MEEA) partnered with gas and electric utilities in Iowa to establish the Iowa residential heating, ventilation, and air conditioning System Adjustment and Verified Efficiency (HVAC SAVE) program, taking it to scale improving the performance and energy efficiency of HVAC systems, growing businesses, and gaining consumer trust.

Bacterial burden in the operating room: impact of airflow systems.

PubMed

Hirsch, Tobias; Hubert, Helmine; Fischer, Sebastian; Lahmer, Armin; Lehnhardt, Marcus; Steinau, Hans-Ulrich; Steinstraesser, Lars; Seipp, Hans-Martin

2012-09-01

Wound infections present one of the most prevalent and frequent complications associated with surgical procedures. This study analyzes the impact of currently used ventilation systems in the operating room to reduce bacterial contamination during surgical procedures. Four ventilation systems (window-based ventilation, supported air nozzle canopy, low-turbulence displacement airflow, and low-turbulence displacement airflow with flow stabilizer) were analyzed. Two hundred seventy-seven surgical procedures in 6 operating rooms of 5 different hospitals were analyzed for this study. Window-based ventilation showed the highest intraoperative contamination (13.3 colony-forming units [CFU]/h) followed by supported air nozzle canopy (6.4 CFU/h; P = .001 vs window-based ventilation) and low-turbulence displacement airflow (3.4 and 0.8 CFU/h; P < .001 vs window-based ventilation and supported air nozzle canopy). The highest protection was provided by the low-turbulence displacement airflow with flow stabilizer (0.7 CFU/h), which showed a highly significant difference compared with the best supported air nozzle canopy theatre (3.9 CFU/h; P < .001). Furthermore, this system showed no increase of contamination in prolonged durations of surgical procedures. This study shows that intraoperative contamination can be significantly reduced by the use of adequate ventilation systems. Copyright © 2012 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

46 CFR 194.15-5 - Ventilation.

Code of Federal Regulations, 2011 CFR

2011-10-01

....15-5 Ventilation. (a) Operations, reactions or experiments which produce toxic, noxious or corrosive...) Ventilation of air conditioning systems serving the chemical laboratory shall be designed so that air cannot...

Impact of building forms on thermal performance and thermal comfort conditions in religious buildings in hot climates: a case study in Sharjah city

NASA Astrophysics Data System (ADS)

Mushtaha, Emad; Helmy, Omar

2017-11-01

The common system used for thermal regulation in mosques of United Arab Emirates (UAE) is the heating, ventilating and air-conditioning (HVAC) system. This system increases demands on energy consumption and increases CO2 emission. A passive design approach is one of the measures to reduce these problems. This study involved an analytical examination of building forms, followed by testing the impact of these forms on its thermal performance and indoor thermal comfort. The tests were conducted using energy simulations software packages. Passive parameters such as shading devices, thermal insulation and natural ventilation were applied in six cases, including the baseline case within each form. The obtained results showed a significant effect of mosque forms as well as passive design techniques on the thermal comfort within the structures. The findings confirmed that the use of passive design alone would not help achieve thermal comfort, but reduce the annual energy consumption by10%. By integrating a hybrid air-conditioning system as another supporting approach, the annual energy consumption could be reduced by 67.5%, which allows for the designing of a much smaller HVAC system.

FiO2 delivered by a turbine portable ventilator with an oxygen concentrator in an Austere environment.

PubMed

Bordes, Julien; Erwan d'Aranda; Savoie, Pierre-Henry; Montcriol, Ambroise; Goutorbe, Philippe; Kaiser, Eric

2014-09-01

Management of critically ill patients in austere environments is a logistic challenge. Availability of oxygen cylinders for the mechanically ventilated patient may be difficult in such a context. A solution is to use a ventilator able to function with an oxygen concentrator. We tested the SeQual Integra™ (SeQual, San Diego, CA) 10-OM oxygen concentrator paired with the Pulmonetic System(®) LTV 1000 ventilator (Pulmonetic Systems, Minneapolis, MN) and evaluated the delivered fraction of inspired oxygen (FiO2) across a range of minute volumes and combinations of ventilator settings. Two LTV 1000 ventilators were tested. The ventilators were attached to a test lung and FiO2 was measured by a gas analyzer. Continuous-flow oxygen was generated by the OC from 0.5 L/min to 10 L/min and injected into the oxygen inlet port of the LTV 1000. Several combinations of ventilator settings were evaluated to determine the factors affecting the delivered FiO2. The LTV 1000 ventilator is a turbine ventilator that is able to deliver high FiO2 when functioning with an oxygen concentrator. However, modifications of the ventilator settings such as increase in minute ventilation affect delivered FiO2 even if oxygen flow is constant on the oxygen concentrator. The ability of an oxygen concentrator to deliver high FiO2 when used with a turbine ventilator makes this method of oxygen delivery a viable alternative to cylinders in austere environments when used with a turbine ventilator. However, FiO2 has to be monitored continuously because delivered FiO2 decreases when minute ventilation is increased. Copyright © 2014 Elsevier Inc. All rights reserved.

Air Leakage and Air Transfer Between Garage and Living Space

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudd, A.

2014-09-01

This research project focused on evaluation of air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multi-point fan pressurization tests and additional zone pressure diagnostic testing characterized the garage and house air leakage, the garage-to-house air leakage, and garage and house pressuremore » relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed. For houses employing whole-house supply ventilation (positive pressure) or balanced ventilation (same pressure effect as the Baseline condition), adherence to the EPA Indoor airPLUS house-to-garage air sealing requirements should be sufficient to expect little to no garage-to-house air transfer.« less

Technology Solutions Case Study: Air Leakage and Air Transfer Between Garage and Living Space, Waldorf, Maryland

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2014-11-01

In this project, Building Science Corporation worked with production homebuilder K. Hovnanian to evaluate air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multipoint fan pressurization tests and additional zone pressure diagnostic testing measured the garage and house air leakage, the garage-to-housemore » air leakage, and garage and house pressure relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed. For houses employing whole-house supply ventilation (positive pressure) or balanced ventilation (same pressure effect as the baseline condition), adherence to the EPA Indoor airPLUS house-to-garage air sealing requirements should be sufficient to expect little to no garage-to-house air transfer.« less

Building America Case Study: Air Leakage and Air Transfer Between Garage and Living Space, Waldorf, Maryland (Fact Sheet)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2014-11-01

This research project focused on evaluation of air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multi-point fan pressurization tests and additional zone pressure diagnostic testing characterized the garage and house air leakage, the garage-to-house air leakage, and garage and house pressuremore » relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed. For houses employing whole-house supply ventilation (positive pressure) or balanced ventilation (same pressure effect as the Baseline condition), adherence to the EPA Indoor airPLUS house-to-garage air sealing requirements should be sufficient to expect little to no garage-to-house air transfer.« less

A ventilation intervention study in classrooms to improve indoor air quality: the FRESH study.

PubMed

Rosbach, Jeannette T M; Vonk, Machiel; Duijm, Frans; van Ginkel, Jan T; Gehring, Ulrike; Brunekreef, Bert

2013-12-17

Classroom ventilation rates often do not meet building standards, although it is considered to be important to improve indoor air quality. Poor indoor air quality is thought to influence both children's health and performance. Poor ventilation in The Netherlands most often occurs in the heating season. To improve classroom ventilation a tailor made mechanical ventilation device was developed to improve outdoor air supply. This paper studies the effect of this intervention. The FRESH study (Forced-ventilation Related Environmental School Health) was designed to investigate the effect of a CO2 controlled mechanical ventilation intervention on classroom CO2 levels using a longitudinal cross-over design. Target CO2 concentrations were 800 and 1200 parts per million (ppm), respectively. The study included 18 classrooms from 17 schools from the north-eastern part of The Netherlands, 12 experimental classrooms and 6 control classrooms. Data on indoor levels of CO2, temperature and relative humidity were collected during three consecutive weeks per school during the heating seasons of 2010-2012. Associations between the intervention and weekly average indoor CO2 levels, classroom temperature and relative humidity were assessed by means of mixed models with random school-effects. At baseline, mean CO2 concentration for all schools was 1335 ppm (range: 763-2000 ppm). The intervention was able to significantly decrease CO2 levels in the intervention classrooms (F (2,10) = 17.59, p < 0.001), with a mean decrease of 491 ppm. With the target set at 800 ppm, mean CO2 was 841 ppm (range: 743-925 ppm); with the target set at 1200 ppm, mean CO2 was 975 ppm (range: 887-1077 ppm). Although the device was not capable of precisely achieving the two predefined levels of CO2, our study showed that classroom CO2 levels can be reduced by intervening on classroom ventilation using a CO2 controlled mechanical ventilation system.

Exposure to airborne particulate matter in the subway system.

PubMed

Martins, Vânia; Moreno, Teresa; Minguillón, María Cruz; Amato, Fulvio; de Miguel, Eladio; Capdevila, Marta; Querol, Xavier

2015-04-01

The Barcelona subway system comprises eight subway lines, at different depths, with different tunnel dimensions, station designs and train frequencies. An extensive measurement campaign was performed in this subway system in order to characterise the airborne particulate matter (PM) measuring its concentration and investigating its variability, both inside trains and on platforms, in two different seasonal periods (warmer and colder), to better understand the main factors controlling it, and therefore the way to improve air quality. The majority of PM in the underground stations is generated within the subway system, due to abrasion and wear of rail tracks, wheels and braking pads caused during the motion of the trains. Substantial variation in average PM concentrations between underground stations was observed, which might be associated to different ventilation and air conditioning systems, characteristics/design of each station and variations in the train frequency. Average PM2.5 concentrations on the platforms in the subway operating hours ranged from 20 to 51 and from 41 to 91 μg m(-3) in the warmer and colder period, respectively, mainly related to the seasonal changes in the subway ventilation systems. The new subway lines with platform screen doors showed PM2.5 concentrations lower than those in the conventional system, which is probably attributable not only to the more advanced ventilation setup, but also to the lower train frequency and the design of the stations. PM concentrations inside the trains were generally lower than those on the platforms, which is attributable to the air conditioning systems operating inside the trains, which are equipped with air filters. This study allows the analysis and quantification of the impact of different ventilation settings on air quality, which provides an improvement on the knowledge for the general understanding and good management of air quality in the subway system. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Employing a Modified Diffuser Momentum Model to Simulate Ventilation of the Orion CEV

NASA Technical Reports Server (NTRS)

Straus, John; Lewis, John F.

2011-01-01

The Ansys CFX CFD modeling tool was used to support the design efforts of the ventilation system for the Orion CEV. CFD modeling was used to establish the flow field within the cabin for several supply configurations. A mesh and turbulence model sensitivity study was performed before the design studies. Results were post-processed for comparison with performance requirements. Most configurations employed straight vaned diffusers to direct and throw the flow. To manage the size of the models, the diffuser vanes were not resolved. Instead, a momentum model was employed to account for the effect of the diffusers. The momentum model was tested against a separate, vane-resolved side study. Results are presented for a single diffuser configuration for a low supply flow case.

Comparison of two humidification systems for long-term noninvasive mechanical ventilation.

PubMed

Nava, S; Cirio, S; Fanfulla, F; Carlucci, A; Navarra, A; Negri, A; Ceriana, P

2008-08-01

There is no consensus concerning the best system of humidification during long-term noninvasive mechanical ventilation (NIMV). In a technical pilot randomised crossover 12-month study, 16 patients with stable chronic hypercapnic respiratory failure received either heated humidification or heat and moisture exchanger. Compliance with long-term NIMV, airway symptoms, side-effects and number of severe acute pulmonary exacerbations requiring hospitalisation were recorded. Two patients died. Intention-to-treat statistical analysis was performed on 14 patients. No significant differences were observed in compliance with long-term NIMV, but 10 out of 14 patients decided to continue long-term NIMV with heated humidification at the end of the trial. The incidence of side-effects, except for dry throat (significantly more often present using heat and moisture exchanger), hospitalisations and pneumonia were not significantly different. In the present pilot study, the use heated humidification and heat and moisture exchanger showed similar tolerance and side-effects, but a higher number of patients decided to continue long-term noninvasive mechanical ventilation with heated humidification. Further larger studies are required in order to confirm these findings.

Particulate matter in animal rooms housing mice in microisolation caging.

PubMed

Langham, Gregory L; Hoyt, Robert F; Johnson, Thomas E

2006-11-01

Reactions to allergens created by laboratory animals are among the most frequently encountered occupational illnesses associated with research animals. Personnel are exposed to these allergens through airborne particulate matter. Although the use of microisolation caging systems can reduce particulate matter concentrations in rooms housing mice, the operating parameters of ventilated caging systems vary extensively. We compared room air in mouse rooms containing 5 different types of caging: 1) individually ventilated caging under positive pressure with filtered intake air and exhaust air returned to the room (VCR+), 2) individually ventilated caging under negative pressure with exhaust air returned to the room (VCR-), 3) individually ventilated caging under positive pressure with exhaust air returned to the heating, ventilation, and air-conditioning (HVAC) system, 4) individually ventilated caging under negative pressure with exhaust air returned to the HVAC system, and 5) static microisolation cages. We found that rooms under VCR conditions had fewer large particles than did those under other conditions, but the numbers of 0.3 microm particles did not differ significantly among systems. Static, positive or negative pressure applied to caging units as well as route of air exhaust were found to have little influence on the total number of particles in the atmosphere. Therefore, considering the heat load, odor, and overall particulate concentration in the room, placing individually ventilated caging under negative pressure with exhaust air returned to the HVAC system appears to be the optimal overall choice when using microisolation housing for rodents.

A randomised crossover comparison of mouth-to-face-shield ventilation and mouth-to-pocket-mask ventilation by surf lifeguards in a manikin.

PubMed

Adelborg, K; Bjørnshave, K; Mortensen, M B; Espeseth, E; Wolff, A; Løfgren, B

2014-07-01

Thirty surf lifeguards (mean (SD) age: 25.1 (4.8) years; 21 male, 9 female) were randomly assigned to perform 2 × 3 min of cardiopulmonary resuscitation on a manikin using mouth-to-face-shield ventilation (AMBU LifeKey) and mouth-to-pocket-mask ventilation (Laerdal Pocket Mask). Interruptions in chest compressions, effective ventilation (visible chest rise) ratio, tidal volume and inspiratory time were recorded. Interruptions in chest compressions per cycle were increased with mouth-to-face-shield ventilation (mean (SD) 8.6 (1.7) s) compared with mouth-to-pocket-mask ventilation (6.9 (1.2) s, p < 0.0001). The proportion of effective ventilations was less using mouth-to-face-shield ventilation (199/242 (82%)) compared with mouth-to-pocket-mask ventilation (239/240 (100%), p = 0.0002). Tidal volume was lower using mouth-to-face-shield ventilation (mean (SD) 0.36 (0.20) l) compared with mouth-to-pocket-mask ventilation (0.45 (0.20) l, p = 0.006). No differences in inspiratory times were observed between mouth-to-face-shield ventilation and mouth-to-pocket-mask ventilation. In conclusion, mouth-to-face-shield ventilation increases interruptions in chest compressions, reduces the proportion of effective ventilations and decreases delivered tidal volumes compared with mouth-to-pocket-mask ventilation. © 2014 The Association of Anaesthetists of Great Britain and Ireland.

Mission Impact Through Neuro-Inspired Design (MIND) Laboratory: Design Principles and Performance Characteristics

DTIC Science & Technology

2013-09-01

sprinkler , fire alarm, and mass-notification systems ). Piping required for the sprinkler system uses dielectric couplers at each penetration of the...environment for neuroscience research designed for studying Soldier- system interactions in support of the U.S. Army Research Laboratory’s (ARL’s...Engineers, of Towson, MD, —designed the heating, ventilation, and air conditioning and electrical systems ; Hi-Tech Services, Inc., of Ferndale, WA

Particle transport in low-energy ventilation systems. Part 1: theory of steady states.

PubMed

Bolster, D T; Linden, P F

2009-04-01

Many modern low-energy ventilation schemes, such as displacement or natural ventilation, take advantage of temperature stratification in a space, extracting the warmest air from the top of the room. The adoption of these energy-efficient ventilation systems still requires the provision of acceptable indoor air quality. In this work we study the steady state transport of particulate contaminants in a displacement-ventilated space. Representing heat sources as ideal sources of buoyancy, analytical models are developed that allow us to compare the average efficiency of contaminant removal between traditional and modern low-energy systems. We found that on average traditional and low-energy systems are similar in overall pollutant removal efficiency, although quite different vertical distributions of contaminant can exist, thus affecting individual exposure. While the main focus of this work is on particles where the dominant mode of deposition is by gravitational settling, we also discuss additional deposition mechanisms and show that the qualitative observations we make carry over to cases where such mechanisms must be included. We illustrate that while average concentration of particles for traditional mixing systems and low energy displacement systems are similar, local concentrations can vary significantly with displacement systems. Depending on the source of the particles this can be better or worse in terms of occupant exposure and engineers should take due diligence accordingly when designing ventilation systems.

Characterization of natural ventilation in wastewater collection systems.

PubMed

Ward, Matthew; Corsi, Richard; Morton, Robert; Knapp, Tom; Apgar, Dirk; Quigley, Chris; Easter, Chris; Witherspoon, Jay; Pramanik, Amit; Parker, Wayne

2011-03-01

The purpose of the study was to characterize natural ventilation in full-scale gravity collection system components while measuring other parameters related to ventilation. Experiments were completed at four different locations in the wastewater collection systems of Los Angeles County Sanitation Districts, Los Angeles, California, and the King County Wastewater Treatment District, Seattle, Washington. The subject components were concrete gravity pipes ranging in diameter from 0.8 to 2.4 m (33 to 96 in.). Air velocity was measured in each pipe using a carbon-monoxide pulse tracer method. Air velocity was measured entering or exiting the components at vents using a standpipe and hotwire anemometer arrangement. Ambient wind speed, temperature, and relative humidity; headspace temperature and relative humidity; and wastewater flow and temperature were measured. The field experiments resulted in a large database of measured ventilation and related parameters characterizing ventilation in full-scale gravity sewers. Measured ventilation rates ranged from 23 to 840 L/s. The experimental data was used to evaluate existing ventilation models. Three models that were based upon empirical extrapolation, computational fluid dynamics, and thermodynamics, respectively, were evaluated based on predictive accuracy compared to the measured data. Strengths and weaknesses in each model were found and these observations were used to propose a concept for an improved ventilation model.

Are we fully utilizing the functionalities of modern operating room ventilators?

PubMed

Liu, Shujie; Kacmarek, Robert M; Oto, Jun

2017-12-01

The modern operating room ventilators have become very sophisticated and many of their features are comparable with those of an ICU ventilator. To fully utilize the functionality of modern operating room ventilators, it is important for clinicians to understand in depth the working principle of these ventilators and their functionalities. Piston ventilators have the advantages of delivering accurate tidal volume and certain flow compensation functions. Turbine ventilators have great ability of flow compensation. Ventilation modes are mainly volume-based or pressure-based. Pressure-based ventilation modes provide better leak compensation than volume-based. The integration of advanced flow generation systems and ventilation modes of the modern operating room ventilators enables clinicians to provide both invasive and noninvasive ventilation in perioperative settings. Ventilator waveforms can be used for intraoperative neuromonitoring during cervical spine surgery. The increase in number of new features of modern operating room ventilators clearly creates the opportunity for clinicians to optimize ventilatory care. However, improving the quality of ventilator care relies on a complete understanding and correct use of these new features. VIDEO ABSTRACT: http://links.lww.com/COAN/A47.

Houses need to breathe--right?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sherman, Max H.

2004-10-01

Houses need to breathe, but we can no longer leave the important functions associated with ventilation to be met accidentally. A designed ventilation system must be considered as much a part of a home as its heating system. Windows are a key part of that system because they allow a quick increase in ventilation for unusual events, but neither they nor a leaky building shell can be counted on to provide minimum levels.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Apte, Michael G.; Norman, Bourassa; Faulkner, David

An improved HVAC system for portable classrooms was specified to address key problems in existing units. These included low energy efficiency, poor control of and provision for adequate ventilation, and excessive acoustic noise. Working with industry, a prototype improved heat pump air conditioner was developed to meet the specification. A one-year measurement-intensive field-test of ten of these IHPAC systems was conducted in occupied classrooms in two distinct California climates. These measurements are compared to those made in parallel in side by side portable classrooms equipped with standard 10 SEER heat pump air conditioner equipment. The IHPAC units were found tomore » work as designed, providing predicted annual energy efficiency improvements of about 36 percent to 42 percent across California's climate zones, relative to 10 SEER units. Classroom ventilation was vastly improved as evidenced by far lower indoor minus outdoor CO2 concentrations. TheIHPAC units were found to provide ventilation that meets both California State energy and occupational codes and the ASHRAE minimum ventilation requirements; the classrooms equipped with the 10 SEER equipment universally did not meet these targets. The IHPAC system provided a major improvement in indoor acoustic conditions. HVAC system generated background noise was reduced in fan-only and fan and compressor modes, reducing the nose levels to better than the design objective of 45 dB(A), and acceptable for additional design points by the Collaborative on High Performance Schools. The IHPAC provided superior ventilation, with indoor minus outdoor CO2 concentrations that showed that the Title 24 minimum ventilation requirement of 15 CFM per occupant was nearly always being met. The opposite was found in the classrooms utilizing the 10 SEER system, where the indoor minus outdoor CO2 concentrations frequently exceeded levels that reflect inadequate ventilation. Improved ventilation conditions in the IHPAC lead to effective removal of volatile organic compounds and aldehydes, on average lowering the concentrations by 57 percent relative to the levels in the 10 SEER classrooms. The average IHPAC to 10 SEER formaldehyde ratio was about 67 percent, indicating only a 33 percent reduction of this compound in indoor air. The IHPAC thermal control system provided less variability in occupied classroom temperature than the 10 SEER thermostats. The average room temperatures in all seasons tended to be slightly lower in the IHPAC classrooms, often below the lower limit of the ASHRAE 55 thermal comfort band. State-wide and national energy modeling provided conservative estimates of potential energy savings by use of the IHPAC system that would provide payback a the range of time far lower than the lifetime of the equipment. Assuming electricity costs of $0.15/kWh, the perclassroom range of savings is from about $85 to $195 per year in California, and about $89 to $250 per year in the U.S., depending upon the city. These modelsdid not include the non-energy benefits to the classrooms including better air quality and acoustic conditions that could lead to improved health and learning in school. Market connection efforts that were part of the study give all indication that this has been a very successful project. The successes include the specification of the IHPAC equipment in the CHPS portable classroom standards, the release of a commercial product based on the standards that is now being installed in schools around the U.S., and the fact that a public utility company is currently considering the addition of the technology to its customer incentive program. These successes indicate that the IHPAC may reach its potential to improve ventilation and save energy in classrooms.« less

30 CFR 57.14213 - Ventilation and shielding for welding.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Ventilation and shielding for welding. 57.14213... welding. (a) Welding operations shall be shielded when performed at locations where arc flash could be hazardous to persons. (b) All welding operations shall be well-ventilated. ...

30 CFR 57.14213 - Ventilation and shielding for welding.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Ventilation and shielding for welding. 57.14213... welding. (a) Welding operations shall be shielded when performed at locations where arc flash could be hazardous to persons. (b) All welding operations shall be well-ventilated. ...

30 CFR 57.14213 - Ventilation and shielding for welding.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Ventilation and shielding for welding. 57.14213... welding. (a) Welding operations shall be shielded when performed at locations where arc flash could be hazardous to persons. (b) All welding operations shall be well-ventilated. ...

30 CFR 57.14213 - Ventilation and shielding for welding.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Ventilation and shielding for welding. 57.14213... welding. (a) Welding operations shall be shielded when performed at locations where arc flash could be hazardous to persons. (b) All welding operations shall be well-ventilated. ...

30 CFR 57.14213 - Ventilation and shielding for welding.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Ventilation and shielding for welding. 57.14213... welding. (a) Welding operations shall be shielded when performed at locations where arc flash could be hazardous to persons. (b) All welding operations shall be well-ventilated. ...

Ventilating Air-Conditioner

NASA Technical Reports Server (NTRS)

Dinh, Khanh

1994-01-01

Air-conditioner provides ventilation designed to be used alone or incorporated into cooling or heating system operates efficiently only by recirculating stale air within building. Energy needed to operate overall ventilating cooling or heating system slightly greater than operating nonventilating cooling or heating system. Helps to preserve energy efficiency while satisfying need for increased forced ventilation to prevent accumulation of undesired gases like radon and formaldehyde. Provides fresh treated air to variety of confined spaces: hospital surgeries, laboratories, clean rooms, and printing shops and other places where solvents used. In mobile homes and portable classrooms, eliminates irritant chemicals exuded by carpets, panels, and other materials, ensuring healthy indoor environment for occupants.

Assessing Respiratory System Mechanical Function.

PubMed

Restrepo, Ruben D; Serrato, Diana M; Adasme, Rodrigo

2016-12-01

The main goals of assessing respiratory system mechanical function are to evaluate the lung function through a variety of methods and to detect early signs of abnormalities that could affect the patient's outcomes. In ventilated patients, it has become increasingly important to recognize whether respiratory function has improved or deteriorated, whether the ventilator settings match the patient's demand, and whether the selection of ventilator parameters follows a lung-protective strategy. Ventilator graphics, esophageal pressure, intra-abdominal pressure, and electric impedance tomography are some of the best-known monitoring tools to obtain measurements and adequately evaluate the respiratory system mechanical function. Copyright © 2016 Elsevier Inc. All rights reserved.

Guide to Technical Documents. Volume 2. January 1983 through December 1983

DTIC Science & Technology

1983-12-01

4) inclu- sion of the fluid-structural interaction. CR 80.023 Flue Gas Desulfurization at Navy Bases, Navy Energy Guidance...availability, costs, and operating performance of industrial-sized flue gas desulfurization (FGD) systems for coal-fired boilers was performed for...to close visual inspection. N-1658 Control Strategies for Reducing Heating, Ventilating, and Air Conditioning (HVAC) Energy Consumption in Single

78 FR 51749 - Proposed Information Collection; Ventilation Plan and Main Fan Maintenance Record (Pertains to...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-21

... maintaining a safe and healthful working environment. A well planned mine ventilation system is necessary to assure a fresh air supply to miners at all working places, to control the amounts of harmful airborne... usually present harsh and hostile working environments. The ventilation system is the most vital life...

Flexible Fabrics with High Thermal Conductivity for Advanced Spacesuits

NASA Technical Reports Server (NTRS)

Trevino, Luis A.; Bue, Grant; Orndoff, Evelyne; Kesterson, Matt; Connel, John W.; Smith, Joseph G., Jr.; Southward, Robin E.; Working, Dennis; Watson, Kent A.; Delozier, Donovan M.

2006-01-01

This paper describes the effort and accomplishments for developing flexible fabrics with high thermal conductivity (FFHTC) for spacesuits to improve thermal performance, lower weight and reduce complexity. Commercial and additional space exploration applications that require substantial performance enhancements in removal and transport of heat away from equipment as well as from the human body can benefit from this technology. Improvements in thermal conductivity were achieved through the use of modified polymers containing thermally conductive additives. The objective of the FFHTC effort is to significantly improve the thermal conductivity of the liquid cooled ventilation garment by improving the thermal conductivity of the subcomponents (i.e., fabric and plastic tubes). This paper presents the initial system modeling studies, including a detailed liquid cooling garment model incorporated into the Wissler human thermal regulatory model, to quantify the necessary improvements in thermal conductivity and garment geometries needed to affect system performance. In addition, preliminary results of thermal conductivity improvements of the polymer components of the liquid cooled ventilation garment are presented. By improving thermal garment performance, major technology drivers will be addressed for lightweight, high thermal conductivity, flexible materials for spacesuits that are strategic technical challenges of the Exploration

Assessment of air velocity sensors for use in animal produciton facilities

USDA-ARS?s Scientific Manuscript database

Ventilation is an integral part of thermal environment control in animal production facilities. Accurately measuring the air velocity distribution within these facilities is cumbersome using the traverse method and a distributed velocity measurement system would reduce the time necessary to perform ...

Clinical challenges in mechanical ventilation.

PubMed

Goligher, Ewan C; Ferguson, Niall D; Brochard, Laurent J

2016-04-30

Mechanical ventilation supports gas exchange and alleviates the work of breathing when the respiratory muscles are overwhelmed by an acute pulmonary or systemic insult. Although mechanical ventilation is not generally considered a treatment for acute respiratory failure per se, ventilator management warrants close attention because inappropriate ventilation can result in injury to the lungs or respiratory muscles and worsen morbidity and mortality. Key clinical challenges include averting intubation in patients with respiratory failure with non-invasive techniques for respiratory support; delivering lung-protective ventilation to prevent ventilator-induced lung injury; maintaining adequate gas exchange in severely hypoxaemic patients; avoiding the development of ventilator-induced diaphragm dysfunction; and diagnosing and treating the many pathophysiological mechanisms that impair liberation from mechanical ventilation. Personalisation of mechanical ventilation based on individual physiological characteristics and responses to therapy can further improve outcomes. Copyright © 2016 Elsevier Ltd. All rights reserved.

46 CFR 58.01-45 - Machinery space, ventilation.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Machinery space, ventilation. 58.01-45 Section 58.01-45... MACHINERY AND RELATED SYSTEMS General Requirements § 58.01-45 Machinery space, ventilation. Each machinery space must be ventilated to ensure that, when machinery or boilers are operating at full power in all...

46 CFR 58.01-45 - Machinery space, ventilation.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Machinery space, ventilation. 58.01-45 Section 58.01-45... MACHINERY AND RELATED SYSTEMS General Requirements § 58.01-45 Machinery space, ventilation. Each machinery space must be ventilated to ensure that, when machinery or boilers are operating at full power in all...

46 CFR 58.01-45 - Machinery space, ventilation.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Machinery space, ventilation. 58.01-45 Section 58.01-45... MACHINERY AND RELATED SYSTEMS General Requirements § 58.01-45 Machinery space, ventilation. Each machinery space must be ventilated to ensure that, when machinery or boilers are operating at full power in all...

46 CFR 58.01-45 - Machinery space, ventilation.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Machinery space, ventilation. 58.01-45 Section 58.01-45... MACHINERY AND RELATED SYSTEMS General Requirements § 58.01-45 Machinery space, ventilation. Each machinery space must be ventilated to ensure that, when machinery or boilers are operating at full power in all...

46 CFR 58.01-45 - Machinery space, ventilation.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Machinery space, ventilation. 58.01-45 Section 58.01-45... MACHINERY AND RELATED SYSTEMS General Requirements § 58.01-45 Machinery space, ventilation. Each machinery space must be ventilated to ensure that, when machinery or boilers are operating at full power in all...

46 CFR 177.600 - Ventilation of enclosed and partially enclosed spaces.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Ventilation of enclosed and partially enclosed spaces... enclosed and partially enclosed spaces. (a) An enclosed or partially enclosed space within a vessel must be adequately ventilated in a manner suitable for the purpose of the space. (b) A power ventilation system must...

46 CFR 116.600 - Ventilation of enclosed and partially enclosed spaces.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Ventilation of enclosed and partially enclosed spaces... spaces. (a) An enclosed or partially enclosed space within a vessel must be adequately ventilated in a manner suitable for the purpose of the space. (b) A power ventilation system must be capable of being...

46 CFR 116.600 - Ventilation of enclosed and partially enclosed spaces.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Ventilation of enclosed and partially enclosed spaces... spaces. (a) An enclosed or partially enclosed space within a vessel must be adequately ventilated in a manner suitable for the purpose of the space. (b) A power ventilation system must be capable of being...

46 CFR 116.600 - Ventilation of enclosed and partially enclosed spaces.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Ventilation of enclosed and partially enclosed spaces... spaces. (a) An enclosed or partially enclosed space within a vessel must be adequately ventilated in a manner suitable for the purpose of the space. (b) A power ventilation system must be capable of being...

46 CFR 177.600 - Ventilation of enclosed and partially enclosed spaces.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Ventilation of enclosed and partially enclosed spaces... enclosed and partially enclosed spaces. (a) An enclosed or partially enclosed space within a vessel must be adequately ventilated in a manner suitable for the purpose of the space. (b) A power ventilation system must...

46 CFR 177.600 - Ventilation of enclosed and partially enclosed spaces.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Ventilation of enclosed and partially enclosed spaces... enclosed and partially enclosed spaces. (a) An enclosed or partially enclosed space within a vessel must be adequately ventilated in a manner suitable for the purpose of the space. (b) A power ventilation system must...

46 CFR 116.600 - Ventilation of enclosed and partially enclosed spaces.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Ventilation of enclosed and partially enclosed spaces... spaces. (a) An enclosed or partially enclosed space within a vessel must be adequately ventilated in a manner suitable for the purpose of the space. (b) A power ventilation system must be capable of being...

46 CFR 116.600 - Ventilation of enclosed and partially enclosed spaces.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Ventilation of enclosed and partially enclosed spaces... spaces. (a) An enclosed or partially enclosed space within a vessel must be adequately ventilated in a manner suitable for the purpose of the space. (b) A power ventilation system must be capable of being...

46 CFR 177.600 - Ventilation of enclosed and partially enclosed spaces.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Ventilation of enclosed and partially enclosed spaces... enclosed and partially enclosed spaces. (a) An enclosed or partially enclosed space within a vessel must be adequately ventilated in a manner suitable for the purpose of the space. (b) A power ventilation system must...

46 CFR 177.600 - Ventilation of enclosed and partially enclosed spaces.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Ventilation of enclosed and partially enclosed spaces... enclosed and partially enclosed spaces. (a) An enclosed or partially enclosed space within a vessel must be adequately ventilated in a manner suitable for the purpose of the space. (b) A power ventilation system must...

Automated Weaning from Mechanical Ventilation after Off-Pump Coronary Artery Bypass Grafting.

PubMed

Fot, Evgenia V; Izotova, Natalia N; Yudina, Angelika S; Smetkin, Aleksei A; Kuzkov, Vsevolod V; Kirov, Mikhail Y

2017-01-01

The discontinuation of mechanical ventilation after coronary surgery may prolong and significantly increase the load on intensive care unit personnel. We hypothesized that automated mode using INTELLiVENT-ASV can decrease duration of postoperative mechanical ventilation, reduce workload on medical staff, and provide safe ventilation after off-pump coronary artery bypass grafting (OPCAB). The primary endpoint of our study was to assess the duration of postoperative mechanical ventilation during different modes of weaning from respiratory support (RS) after OPCAB. The secondary endpoint was to assess safety of the automated weaning mode and the number of manual interventions to the ventilator settings during the weaning process in comparison with the protocolized weaning mode. Forty adult patients undergoing elective OPCAB were enrolled into a prospective single-center study. Patients were randomized into two groups: automated weaning ( n  = 20) using INTELLiVENT-ASV mode with quick-wean option; and protocolized weaning ( n  = 20), using conventional synchronized intermittent mandatory ventilation (SIMV) + pressure support (PS) mode. We assessed the duration of postoperative ventilation, incidence and duration of unacceptable RS, and the load on medical staff. We also performed the retrospective analysis of 102 patients (standard weaning) who were weaned from ventilator with SIMV + PS mode based on physician's experience without prearranged algorithm. Realization of the automated weaning protocol required change in respiratory settings in 2 patients vs. 7 (5-9) adjustments per patient in the protocolized weaning group. Both incidence and duration of unacceptable RS were reduced significantly by means of the automated weaning approach. The FiO 2 during spontaneous breathing trials was significantly lower in the automated weaning group: 30 (30-35) vs. 40 (40-45) % in the protocolized weaning group ( p  < 0.01). The average time until tracheal extubation did not differ in the automated weaning and the protocolized weaning groups: 193 (115-309) and 197 (158-253) min, respectively, but increased to 290 (210-411) min in the standard weaning group. The automated weaning system after off-pump coronary surgery might provide postoperative ventilation in a more protective way, reduces the workload on medical staff, and does not prolong the duration of weaning from ventilator. The use of automated or protocolized weaning can reduce the duration of postoperative mechanical ventilation in comparison with non-protocolized weaning based on the physician's decision.

Limiting ventilator-induced lung injury through individual electronic medical record surveillance.

PubMed

Herasevich, Vitaly; Tsapenko, Mykola; Kojicic, Marija; Ahmed, Adil; Kashyap, Rachul; Venkata, Chakradhar; Shahjehan, Khurram; Thakur, Sweta J; Pickering, Brian W; Zhang, Jiajie; Hubmayr, Rolf D; Gajic, Ognjen

2011-01-01

To improve the safety of ventilator care and decrease the risk of ventilator-induced lung injury, we designed and tested an electronic algorithm that incorporates patient characteristics and ventilator settings, allowing near-real-time notification of bedside providers about potentially injurious ventilator settings. Electronic medical records of consecutive patients who received invasive ventilation were screened in three Mayo Clinic Rochester intensive care units. The computer system alerted bedside providers via the text paging notification about potentially injurious ventilator settings. Alert criteria included a Pao2/Fio2 ratio of <300 mm Hg, free text search for the words "edema" or "bilateral + infiltrates" on the chest radiograph report, a tidal volume of >8 mL/kg predicted body weight (based on patient gender and height), a plateau pressure of >30 cm H2O, and a peak airway pressure of >35 cm H2O. Respiratory therapists answered a brief online satisfaction survey. Ventilator-induced lung injury risk was compared before and after the introduction of ventilator-induced lung injury alert. The prevalence of acute lung injury was 42% (n = 490) among 1,159 patients receiving >24 hrs of invasive ventilation. The system sent 111 alerts for 80 patients, with a positive predictive value of 59%. The exposure to potentially injurious ventilation decreased after the intervention from 40.6 ± 74.6 hrs to 26.9 ± 77.3 hrs (p = .004). Electronic medical record surveillance of mechanically ventilated patients accurately detects potentially injurious ventilator settings and is able to influence bedside practice at moderate costs. Its implementation is associated with decreased patient exposure to potentially injurious mechanical ventilation settings.

Hygiene guideline for the planning, installation, and operation of ventilation and air-conditioning systems in health-care settings - Guideline of the German Society for Hospital Hygiene (DGKH).

PubMed

Külpmann, Rüdiger; Christiansen, Bärbel; Kramer, Axel; Lüderitz, Peter; Pitten, Frank-Albert; Wille, Frank; Zastrow, Klaus-Dieter; Lemm, Friederike; Sommer, Regina; Halabi, Milo

2016-01-01

Since the publication of the first "Hospital Hygiene Guideline for the implementation and operation of air conditioning systems (HVAC systems) in hospitals" (http://www.krankenhaushygiene.de/informationen/fachinformationen/leitlinien/12) in 2002, it was necessary due to the increase in knowledge, new regulations, improved air-conditioning systems and advanced test methods to revise the guideline. Based on the description of the basic features of ventilation concepts, its hygienic test and the usage-based requirements for ventilation, the DGKH section "Ventilation and air conditioning technology" attempts to provide answers for the major air quality issues in the planning, design and the hygienically safe operation of HVAC systems in rooms of health care.

New control design principles based on measured performance and energy analysis of HVAC (Heating, Ventilating, and Air-Conditioning) systems

NASA Astrophysics Data System (ADS)

Hittle, D. C.; Johnson, D. L.

1985-01-01

This report is one of a series on the development of heating, ventilating, and air-conditioning (HVAC) control systems that are simple, efficient, reliable, maintainable, and well-documented. This report identifies major problems associated with three currently used HVAC control systems. It also describes the development of a retrofit control system applicable to military buildings that will allow easy identification of component failures, facilitate repair, and minimize system failures. Evaluation of currently used controls showed that pneumatic temperature control equipment requires a very clean source of supply air and is also not very accurate. Pneumatic, rather than electronic, actuators should be used because they are cheaper and require less maintenance. Thermistor temperature detectors should not be used for HVAC applications because they require frequent calibration. It was found that enthalpy economy cycles cannot be used for control because the humidity sensors required for their use are prone to rapid drift, inaccurate, and hard to calibrate in the field. Performance of control systems greatly affects HVAC operating costs. Significant savings can be achieved if proportional-plus-integral control schemes are used. Use of the retrofit prototype control panel developed in this study on variable-air-volume systems should provide significant energy cost savings, improve comfort and reliability, and reduce maintenance costs.

Using cognitive task analysis to facilitate the integration of decision support systems into the neonatal intensive care unit.

PubMed

Baxter, Gordon D; Monk, Andrew F; Tan, Kenneth; Dear, Peter R F; Newell, Simon J

2005-11-01

New medical systems may be rejected by staff because they do not integrate with local practice. An expert system, FLORENCE, is being developed to help staff in a neonatal intensive care unit (NICU) make decisions about ventilator settings when treating babies with respiratory distress syndrome. For FLORENCE to succeed it must be clinically useful and acceptable to staff in the context of local work practices. The aim of this work was to identify those contextual factors that would affect FLORENCE's success. A cognitive task analysis (CTA) of the NICU was performed. First, work context analysis was used to identify how work is performed in the NICU. Second, the critical decision method (CDM) was used to analyse how staff make decisions about changing the ventilator settings. Third, naturalistic observation of staff's use of the ventilator was performed. A. The work context analysis identified the NICU's hierarchical communication structure and the importance of numerous types of record in communication. B. It also identified important ergonomic and practical requirements for designing the displays and positioning the computer. C. The CDM interviews suggested instances where problems can arise if the data used by FLORENCE, which is automatically read, is not manually verified. D. Observation showed that most alarms cleared automatically. When FLORENCE raises an alarm, staff will normally be required to intervene and make a clinical judgement, even if the ventilator settings are not subsequently changed. FLORENCE must not undermine the NICU's hierarchical communication channels (A). The re-design of working practices to incorporate FLORENCE, reinforced through its user interface, must ensure that expert help is called on when appropriate (A). The procedures adopted with FLORENCE should ensure that the data the advice is based upon is valid (C). For example, FLORENCE could prompt staff to manually verify the data before implementing any suggested changes. FLORENCE's audible alarm should be clearly distinguishable from other NICU alarms (D); new procedures should be established to ensure that FLORENCE alarms receive attention (D), and false alarms from FLORENCE should be minimised (B, D). FLORENCE should always provide the data and reasoning underpinning its advice (A, C, D). The methods used in the CTA identified several contextual issues that could affect FLORENCE's acceptance. These issues, which extend beyond FLORENCE's capability to suggest changes to the ventilator settings, are being addressed in the design of the user interface and plans for FLORENCE's subsequent deployment.

The School Advanced Ventilation Engineering Software (SAVES)

EPA Pesticide Factsheets

The School Advanced Ventilation Engineering Software (SAVES) package is a tool to help school designers assess the potential financial payback and indoor humidity control benefits of Energy Recovery Ventilation (ERV) systems for school applications.

Effects of ventilation behaviour on indoor heat load based on test reference years.

PubMed

Rosenfelder, Madeleine; Koppe, Christina; Pfafferott, Jens; Matzarakis, Andreas

2016-02-01

Since 2003, most European countries established heat health warning systems to alert the population to heat load. Heat health warning systems are based on predicted meteorological conditions outdoors. But the majority of the European population spends a substantial amount of time indoors, and indoor thermal conditions can differ substantially from outdoor conditions. The German Meteorological Service (Deutscher Wetterdienst, DWD) extended the existing heat health warning system (HHWS) with a thermal building simulation model to consider heat load indoors. In this study, the thermal building simulation model is used to simulate a standardized building representing a modern nursing home, because elderly and sick people are most sensitive to heat stress. Different types of natural ventilation were simulated. Based on current and future test reference years, changes in the future heat load indoors were analyzed. Results show differences between the various ventilation options and the possibility to minimize the thermal heat stress during summer by using an appropriate ventilation method. Nighttime ventilation for indoor thermal comfort is most important. A fully opened window at nighttime and the 2-h ventilation in the morning and evening are more sufficient to avoid heat stress than a tilted window at nighttime and the 1-h ventilation in the morning and the evening. Especially the ventilation in the morning seems to be effective to keep the heat load indoors low. Comparing the results for the current and the future test reference years, an increase of heat stress on all ventilation types can be recognized.

Effects of ventilation behaviour on indoor heat load based on test reference years

NASA Astrophysics Data System (ADS)

Rosenfelder, Madeleine; Koppe, Christina; Pfafferott, Jens; Matzarakis, Andreas

2016-02-01

Since 2003, most European countries established heat health warning systems to alert the population to heat load. Heat health warning systems are based on predicted meteorological conditions outdoors. But the majority of the European population spends a substantial amount of time indoors, and indoor thermal conditions can differ substantially from outdoor conditions. The German Meteorological Service (Deutscher Wetterdienst, DWD) extended the existing heat health warning system (HHWS) with a thermal building simulation model to consider heat load indoors. In this study, the thermal building simulation model is used to simulate a standardized building representing a modern nursing home, because elderly and sick people are most sensitive to heat stress. Different types of natural ventilation were simulated. Based on current and future test reference years, changes in the future heat load indoors were analyzed. Results show differences between the various ventilation options and the possibility to minimize the thermal heat stress during summer by using an appropriate ventilation method. Nighttime ventilation for indoor thermal comfort is most important. A fully opened window at nighttime and the 2-h ventilation in the morning and evening are more sufficient to avoid heat stress than a tilted window at nighttime and the 1-h ventilation in the morning and the evening. Especially the ventilation in the morning seems to be effective to keep the heat load indoors low. Comparing the results for the current and the future test reference years, an increase of heat stress on all ventilation types can be recognized.

Building Component Maintenance and Repair Data Base: Heating, Ventilating, and Air Conditioning (HVAC) Systems

DTIC Science & Technology

1991-05-01

Building Component Maintenance and Repair Data Base: Heating, Ventilating, and Air Conditioning (HVAC) Systems by Edgar S. Neely Robert D. Neathammer...Repair Data Base: Heating, Ventilating, and Air Conditioning (HVAC) Systems RDTE dated 1980EIMB 1984 - 1989 6. AUTHOR(S) Edgar S. Neely, Robert D...Laboratory (USACERL). The Principal Investigators were Dr. Edgar Neely and Mr. Robert Neathammer (USACERL-FS). The primary contractor for much of the

30 CFR 56.14213 - Ventilation and shielding for welding.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Ventilation and shielding for welding. 56.14213... Equipment Safety Practices and Operational Procedures § 56.14213 Ventilation and shielding for welding. (a) Welding operations shall be shielded when performed at locations where arc flash could be hazardous to...

30 CFR 56.14213 - Ventilation and shielding for welding.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Ventilation and shielding for welding. 56.14213... Equipment Safety Practices and Operational Procedures § 56.14213 Ventilation and shielding for welding. (a) Welding operations shall be shielded when performed at locations where arc flash could be hazardous to...

30 CFR 56.14213 - Ventilation and shielding for welding.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Ventilation and shielding for welding. 56.14213... Equipment Safety Practices and Operational Procedures § 56.14213 Ventilation and shielding for welding. (a) Welding operations shall be shielded when performed at locations where arc flash could be hazardous to...

30 CFR 56.14213 - Ventilation and shielding for welding.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Ventilation and shielding for welding. 56.14213... Equipment Safety Practices and Operational Procedures § 56.14213 Ventilation and shielding for welding. (a) Welding operations shall be shielded when performed at locations where arc flash could be hazardous to...

30 CFR 56.14213 - Ventilation and shielding for welding.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Ventilation and shielding for welding. 56.14213... Equipment Safety Practices and Operational Procedures § 56.14213 Ventilation and shielding for welding. (a) Welding operations shall be shielded when performed at locations where arc flash could be hazardous to...

Operating and maintaining your heat recovery ventilator (HRV) -- Revised edition. Home heating and cooling series, Number 8

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

Heat recovery ventilators (HRVs) differ from other mechanical ventilation devices by their ability to exchange heat between supply and exhaust air streams, which reduces the cost of heating or cooling fresh air. This booklet discusses the need for mechanical ventilation in conventional and energy-efficient homes, an explains the components of a HRV system, how to operate and maintain the system, and how to solve operating problems. A maintenance chart and schedule and a HRV troubleshooting guide are included.

Tracheostomy and invasive mechanical ventilation in amyotrophic lateral sclerosis: decision-making factors and survival analysis.

PubMed

Kimura, Fumiharu

2016-04-28

Invasive and/or non-invasive mechanical ventilation are most important options of respiratory management in amyotrophic lateral sclerosis. We evaluated the frequency, clinical characteristics, decision-making factors about ventilation and survival analysis of 190 people with amyotrophic lateral sclerosis patients from 1990 until 2013. Thirty-one percentage of patients underwent tracheostomy invasive ventilation with the rate increasing more than the past 20 years. The ratio of tracheostomy invasive ventilation in patients >65 years old was significantly increased after 2000 (25%) as compared to before (10%). After 2010, the standard use of non-invasive ventilation showed a tendency to reduce the frequency of tracheostomy invasive ventilation. Mechanical ventilation prolonged median survival (75 months in tracheostomy invasive ventilation, 43 months in non-invasive ventilation vs natural course, 32 months). The life-extending effects by tracheostomy invasive ventilation were longer in younger patients ≤65 years old at the time of ventilation support than in older patients. Presence of partners and care at home were associated with better survival. Following factors related to the decision to perform tracheostomy invasive ventilation: patients ≤65 years old: greater use of non-invasive ventilation: presence of a spouse: faster tracheostomy: higher progression rate; and preserved motor functions. No patients who underwent tracheostomy invasive ventilation died from a decision to withdraw mechanical ventilation. The present study provides factors related to decision-making process and survival after tracheostomy and help clinicians and family members to expand the knowledge about ventilation.

Health and Wellbeing of Occupants in Highly Energy Efficient Buildings: A Field Study.

PubMed

Wallner, Peter; Tappler, Peter; Munoz, Ute; Damberger, Bernhard; Wanka, Anna; Kundi, Michael; Hutter, Hans-Peter

2017-03-19

Passive houses and other highly energy-efficient buildings need mechanical ventilation. However, ventilation systems in such houses are regarded with a certain degree of skepticism by parts of the public due to alleged negative health effects. Within a quasi-experimental field study, we investigated if occupants of two types of buildings (mechanical vs. natural ventilation) experience different health, wellbeing and housing satisfaction outcomes and if associations with indoor air quality exist. We investigated 123 modern homes (test group: with mechanical ventilation; control group: naturally ventilated) built in the years 2010 to 2012 in the same geographic area and price range. Interviews of occupants based on standardized questionnaires and measurements of indoor air quality parameters were conducted twice (three months after moving in and one year later). In total, 575 interviews were performed (respondents' mean age 37.9 ± 9 years in the test group, 37.7 ± 9 years in the control group). Occupants of the test group rated their overall health status and that of their children not significantly higher than occupants of the control group at both time points. Adult occupants of the test group reported dry eyes statistically significantly more frequently compared to the control group (19.4% vs. 12.5%). Inhabitants of energy-efficient, mechanically ventilated homes rated the quality of indoor air and climate significantly higher. Self-reported health improved more frequently in the mechanically ventilated new homes ( p = 0.005). Almost no other significant differences between housing types and measuring time points were observed concerning health and wellbeing or housing satisfaction. Associations between vegetative symptoms (dizziness, nausea, headaches) and formaldehyde concentrations as well as between CO₂ levels and perceived stale air were observed. However, both associations were independent of the type of ventilation. In summary, occupants of the mechanically ventilated homes rated their health status slightly higher and their health improved significantly more frequently than in occupants of the control group. As humidity in homes with mechanical ventilation was lower, it seems plausible that the inhabitants reported dry eyes more frequently.

Impact of different-sized laminar air flow versus no laminar air flow on bacterial counts in the operating room during orthopedic surgery.

PubMed

Diab-Elschahawi, Magda; Berger, Jutta; Blacky, Alexander; Kimberger, Oliver; Oguz, Ruken; Kuelpmann, Ruediger; Kramer, Axel; Assadian, Ojan

2011-09-01

This study investigated the influence of the size of unidirectional ceiling distribution systems on counts of viable microorganisms recovered at defined sites in operating room (ORs) and on instrument tables during orthopedic surgery. We compared bacterial sedimentation during 80 orthopedic surgeries. A total of 19 surgeries were performed in ORs with a large (518 cm × 380 cm) unidirectional ceiling distribution (colloquially known as laminar air flow [LAF]) ventilation system, 21 procedures in ORs with a small (380 cm × 120 cm) LAF system, and 40 procedures in ORs with no LAF system. Bacterial sedimentation was evaluated using both settle plates and nitrocellulose membranes. Multivariate linear regression analysis revealed that the colony-forming unit count on nitrocellulose membranes positioned on the instrument table was significantly associated only with the size of the unidirectional LAF distribution system (P < .001), not with the duration of the surgical intervention (P = .753) or with the number of persons present during the surgical intervention (P = .291). Our findings indicate that simply having an LAF ventilation system in place will not provide bacteria-free conditions at the surgical site and on the instrument table. In view of the limited number of procedures studied, our findings require confirmation and further investigations on the ideal, but affordable, size of LAF ventilation systems. Copyright © 2011 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

The seasonal performance of a liquid-desiccant air conditioner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowenstein, A.; Novosel, D.

1995-08-01

Prior reports on liquid-desiccant systems have focused on their steady-state operation at ARI design conditions. By studying their performance during an entire cooling season, the computer modeling presented here shows that liquid-desiccant systems can have a very high seasonal coefficient of performance (COP). For a liquid-desiccant system that uses a double-effect boiler, COPs ranging from 1.44 in a humid location (Houston) to 2.24 in a dry location (Phoenix) are achieved by fully exploiting indirect evaporative cooling and providing only the minimum latent cooling needed to meet the loads on the building. This minimizes the amount of water absorbed by themore » desiccant and, hence, the amount of thermal energy needed to regenerate it. In applications where latent loads are very high, such as processing the high volumes of ventilation air required to maintain good indoor air quality, the liquid-desiccant air conditioner again has an advantage over vapor-compression equipment. In this study, a liquid-desiccant system is modeled that cools and dehumidifies only the ventilation air of an office building in Atlanta. Although processing an airstream that is only 25% of the total air delivered to the building, the liquid-desiccant system is able to meet 52% of the building`s seasonal cooling requirements and reduce the building`s peak electrical demand by about 47%.« less

Face mask ventilation in edentulous patients: a comparison of mandibular groove and lower lip placement.

PubMed

Racine, Stéphane X; Solis, Audrey; Hamou, Nora Ait; Letoumelin, Philippe; Hepner, David L; Beloucif, Sadek; Baillard, Christophe

2010-05-01

In edentulous patients, it may be difficult to perform face mask ventilation because of inadequate seal with air leaks. Our aim was to ascertain whether the "lower lip" face mask placement, as a new face mask ventilation method, is more effective at reducing air leaks than the standard face mask placement. Forty-nine edentulous patients with inadequate seal and air leak during two-hand positive-pressure ventilation using the ventilator circle system were prospectively evaluated. In the presence of air leaks, defined as a difference of at least 33% between inspired and expired tidal volumes, the mask was placed in a lower lip position by repositioning the caudal end of the mask above the lower lip while maintaining the head in extension. The results are expressed as mean +/- SD or median (25th-75th percentiles). Patient characteristics included age (71 +/- 11 yr) and body mass index (24 +/- 4 kg/m2). By using the standard method, the median inspired and expired tidal volumes were 450 ml (400-500 ml) and 0 ml (0-50 ml), respectively, and the median air leak was 400 ml (365-485 ml). After placing the mask in the lower lip position, the median expired tidal volume increased to 400 ml (380-490), and the median air leak decreased to 10 ml (0-20 ml) (P < 0.001 vs. standard method). The lower lip face mask placement with two hands reduced the air leak by 95% (80-100%). In edentulous patients with inadequate face mask ventilation, the lower lip face mask placement with two hands markedly reduced the air leak and improved ventilation.

Particle transport in low-energy ventilation systems. Part 2: Transients and experiments.

PubMed

Bolster, D T; Linden, P F

2009-04-01

Providing adequate indoor air quality while reducing energy consumption is a must for efficient ventilation system design. In this work, we study the transport of particulate contaminants in a displacement-ventilated space, using the idealized 'emptying filling box' model (P.F. Linden, G.F. Lane-serff and D.A. Smeed (1990) Emptying filling boxes: the fluid mechanics of natural ventilation, J. fluid Mech., 212, 309-335.). In this paper, we focused on transient contaminant transport by modeling three transient contamination scenarios, namely the so called 'step-up', 'step-down', and point source cases. Using analytical integral models and numerical models we studied the transient behavior of each of these three cases. We found that, on average, traditional and low-energy systems can be similar in overall pollutant removal efficiency, although quite different vertical gradients can exist. This plays an important role in estimating occupant exposure to contaminant. A series of laboratory experiments were conducted to validate the developed models. The results presented here illustrate that the source location plays a very important role in the distribution of contaminant concentration for spaces ventilated by low energy displacement-ventilation systems. With these results and the knowledge of typical contaminant sources for a given type of space practitioners can design or select more effective systems for the purpose at hand.

Effect of central ventilation and air conditioner system on the concentration and health risk from airborne polycyclic aromatic hydrocarbons.

PubMed

Lv, Jinze; Zhu, Lizhong

2013-03-01

Central ventilation and air conditioner systems are widely utilized nowadays in public places for air exchange and temperature control, which significantly influences the transfer of pollutants between indoors and outdoors. To study the effect of central ventilation and air conditioner systems on the concentration and health risk from airborne pollutants, a spatial and temporal survey was carried out using polycyclic aromatic hydrocarbons (PAHs) as agent pollutants. During the period when the central ventilation system operated without air conditioning (AC-off period), concentrations of 2-4 ring PAHs in the model supermarket were dominated by outdoor levels, due to the good linearity between indoor air and outdoor air (r(p) > 0.769, p < 0.05), and the slopes (1.2-4.54) indicated that ventilating like the model supermarket increased the potential health risks from low molecular weight PAHs. During the period when the central ventilation and air conditioner systems were working simultaneously (AC-on period), although the total levels of PAHs were increased, the concentrations and percentage of the particulate PAHs indoors declined significantly. The BaP equivalency (BaPeq) concentration indicated that utilization of air conditioning reduced the health risks from PAHs in the model supermarket.

Heat Exchanger/Humidifier Trade Study and Conceptual Design for the Constellation Space Suit Portable Life Support System Ventilation Subsystem

NASA Technical Reports Server (NTRS)

Paul, Heather L.; Sompayrac, Robert; Conger, Bruce; Chamberlain, Mateo

2009-01-01

As development of the Constellation Space Suit Element progresses, designing the most effective and efficient life support systems is critical. The baseline schematic analysis for the Portable Life Support System (PLSS) indicates that the ventilation loop will need some method of heat exchange and humidification prior to entering the helmet. A trade study was initiated to identify the challenges associated with conditioning the spacesuit breathing gas stream for temperature and water vapor control, to survey technological literature and resources on heat exchanger and humidifiers to provide solutions to the problems of conditioning the spacesuit breathing gas stream, and to propose potential candidate technologies to perform the heat exchanger and humidifier functions. This paper summarizes the results of this trade study and also describes the conceptual designs that NASA developed to address these issues.

Heat Exchanger/Humidifier Trade Study and Conceptual Design for the Constellation Space Suit Portable Life Support System Ventilation Subsystem

NASA Technical Reports Server (NTRS)

Paul, Heather L.; Conger, Bruce; Sompyrac, Robert; Chamberlain, Mateo

2008-01-01

As development of the Constellation Space Suit Element progresses, designing the most effective and efficient life support systems is critical. The baseline schematic analysis for the Portable Life Support System (PLSS) indicates that the ventilation loop will need some method of heat exchange and humidification prior to entering the helmet. A trade study was initiated to identify the challenges associated with conditioning the spacesuit breathing gas stream for temperature and water vapor control, to survey technological literature and resources on heat exchanger and humidifiers to provide solutions to the problems of conditioning the spacesuit breathing gas stream, and to propose potential candidate technologies to perform the heat exchanger and humidifier functions. This paper summarizes the results of this trade study and also describes the conceptual designs that NASA developed to address these issues.

Preoperational test report, recirculation ventilation systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clifton, F.T.

1997-11-11

This represents a preoperational test report for Recirculation Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102 and supports the ability to exhaust air from each tank. Each system consists of a valved piping loop, a fan, condenser, and moisture separator; equipment is located inside each respective tank farm in its own hardened building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

Optimal ventilation of the anesthetized pediatric patient.

PubMed

Feldman, Jeffrey M

2015-01-01

Mechanical ventilation of the pediatric patient is challenging because small changes in delivered volume can be a significant fraction of the intended tidal volume. Anesthesia ventilators have traditionally been poorly suited to delivering small tidal volumes accurately, and pressure-controlled ventilation has become used commonly when caring for pediatric patients. Modern anesthesia ventilators are designed to deliver small volumes accurately to the patient's airway by compensating for the compliance of the breathing system and delivering tidal volume independent of fresh gas flow. These technology advances provide the opportunity to implement a lung-protective ventilation strategy in the operating room based upon control of tidal volume. This review will describe the capabilities of the modern anesthesia ventilator and the current understanding of lung-protective ventilation. An optimal approach to mechanical ventilation for the pediatric patient is described, emphasizing the importance of using bedside monitors to optimize the ventilation strategy for the individual patient.

New Control Design Principles Based on Measured Performance and Energy Analysis of HVAC (Heating, Ventilating, and Air-Conditioning) Systems.

DTIC Science & Technology

1985-01-01

components must also perform accurately if control is to be accurate, tests were made to determine if these components were likely to introduce more...efficient. However, it also greatly increases the com- plexity of the control systems, since room temperature measurements must be made for each zone, with...involving a psychrometer (a dry-bulb and a wet-bulb mercury thermometer) provides only a rough indication. Calibration is time- consuming and only partly

A new prototype of an electronic jet-ventilator and its humidification system

PubMed Central

Kraincuk, Paul; Kepka, Anton; Ihra, Gerald; Schabernig, Christa; Aloy, Alexander

1999-01-01

Background: Adequate humidification in long-term jet ventilation is a critical aspect in terms of clinical safety. Aim: To assess a prototype of an electronic jet-ventilator and its humidification system. Methods: Forty patients with respiratory insufficiency were randomly allocated to one of four groups. The criterion for inclusion in this study was respiratory insufficiency exhibiting a Murray score above 2. The four groups of patients were ventilated with three different respirators and four different humidification systems. Patients in groups A and B received superimposed high-frequency jet ventilation (SHFJV) by an electronic jet-ventilator either with (group A) or without (group B) an additional humidification system. Patients in group C received high-frequency percussive ventilation (HFPV) by a pneumatic high-frequency respirator, using a hot water humidifier for warming and moistening the inspiration gas. Patients in group D received conventional mechanical ventilation using a standard intensive care unit respirator with a standard humidification system. SHFJV and HFPV were used for a period of 100 h (4days). Results: A significantly low inspiration gas temperature was noted in patients in group B, initially (27.2 ± 2.5°C) and after 2 days (28.0 ± 1.6°C) (P < 0.05). The percentage of relative humidity of the inspiration gas in patients in group B was also initially significantly low (69.8 ± 4.1%; P < 0.05) but rose to an average of 98 ± 2.8% after 2 h. The average percentage across all four groups amounted to 98 ± 0.4% after 2 h. Inflammation of the tracheal mucosa was found in patients in group B and the mucosal injury score (MIS) was significantly higher than in all the other groups. Patients in groups A, C and D showed no severe evidence of airway damage, exhibiting adequate values of relative humidity and temperature of the inspired gas. Conclusion: The problems of humidification associated with jet ventilation can be fully prevented by using this new jet-ventilator. These data were sustained by nondeteriorating MIS values at the end of the 4-day study period in groups A, C and D. PMID:11056732

Evaluating Moisture Control of Variable-Capacity Heat Pumps in Mechanically Ventilated, Low-Load Homes in Climate Zone 2A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Eric; Withers, Chuck; McIlvaine, Janet

Low-load homes can present a challenge when selecting appropriate space-conditioning equipment. Conventional, fixed-capacity heating and cooling equipment is often oversized for small homes, causing increased first costs and operating costs. This report evaluates the performance of variable-capacity comfort systems, with a focus on inverter-driven, variable-capacity systems, as well as proposed system enhancements.

Trends in mechanical ventilation: are we ventilating our patients in the best possible way?

PubMed

Dellaca', Raffaele L; Veneroni, Chiara; Farre', Ramon

2017-06-01

This review addresses how the combination of physiology, medicine and engineering principles contributed to the development and advancement of mechanical ventilation, emphasising the most urgent needs for improvement and the most promising directions of future development. Several aspects of mechanical ventilation are introduced, highlighting on one side the importance of interdisciplinary research for further development and, on the other, the importance of training physicians sufficiently on the technological aspects of modern devices to exploit properly the great complexity and potentials of this treatment. To learn how mechanical ventilation developed in recent decades and to provide a better understanding of the actual technology and practice.To learn how and why interdisciplinary research and competences are necessary for providing the best ventilation treatment to patients.To understand which are the most relevant technical limitations in modern mechanical ventilators that can affect their performance in delivery of the treatment.To better understand and classify ventilation modes.To learn the classification, benefits, drawbacks and future perspectives of automatic ventilation tailoring algorithms.

Low tidal volume mechanical ventilation against no ventilation during cardiopulmonary bypass heart surgery (MECANO): study protocol for a randomized controlled trial.

PubMed

Nguyen, Lee S; Merzoug, Messaouda; Estagnasie, Philippe; Brusset, Alain; Law Koune, Jean-Dominique; Aubert, Stephane; Waldmann, Thierry; Grinda, Jean-Michel; Gibert, Hadrien; Squara, Pierre

2017-12-02

Postoperative pulmonary complications are a leading cause of morbidity and mortality after cardiac surgery. There are no recommendations on mechanical ventilation associated with cardiopulmonary bypass (CPB) during surgery and anesthesiologists perform either no ventilation (noV) at all during CPB or maintain low tidal volume (LTV) ventilation. Indirect evidence points towards better pulmonary outcomes when LTV is performed but no large-scale prospective trial has yet been published in cardiac surgery. The MECANO trial is a single-center, double-blind, randomized, controlled trial comparing two mechanical ventilation strategies, noV and LTV, during cardiac surgery with CPB. In total, 1500 patients are expected to be included, without any restrictions. They will be randomized between noV and LTV on a 1:1 ratio. The noV group will receive no ventilation during CPB. The LTV group will receive 5 breaths/minute with a tidal volume of 3 mL/kg and positive end-expiratory pressure of 5 cmH2O. The primary endpoint will be a composite of all-cause mortality, early respiratory failure defined as a ratio of partial pressure of oxygen/fraction of inspired oxygen <200 mmHg at 1 hour after arrival in the ICU, heavy oxygenation support (defined as a patient requiring either non-invasive ventilation, mechanical ventilation or high-flow oxygen) at 2 days after arrival in the ICU or ventilator-acquired pneumonia defined by the Center of Disease Control. Lung recruitment maneuvers will be performed in the noV and LTV groups at the end of surgery and at arrival in ICU with an insufflation at +30 cmH20 for 5 seconds. Secondary endpoints are those composing the primary endpoint with the addition of pneumothorax, CPB duration, quantity of postoperative bleeding, red blood cell transfusions, revision surgery requirements, length of stay in the ICU and in the hospital and total hospitalization costs. Patients will be followed until hospital discharge. The MECANO trial is the first of its kind to compare in a double-blind design, a no-ventilation to a low-tidal volume strategy for mechanical ventilation during cardiac surgery with CPB, with a primary composite outcome including death, respiratory failure and postoperative pneumonia. ClinicalTrials.gov, NCT03098524 . Registered on 27 February 2017.

Ventilation heterogeneity measured by multiple breath inert gas testing is not affected by inspired oxygen concentration in healthy humans

PubMed Central

Elliott, Ann R.; Prisk, G. Kim; Darquenne, Chantal

2017-01-01

Multiple breath washout (MBW) and oxygen-enhanced MRI techniques use acute exposure to 100% oxygen to measure ventilation heterogeneity. Implicit is the assumption that breathing 100% oxygen does not induce changes in ventilation heterogeneity; however, this is untested. We hypothesized that ventilation heterogeneity decreases with increasing inspired oxygen concentration in healthy subjects. We performed MBW in 8 healthy subjects (4 women, 4 men; age = 43 ± 15 yr) with normal pulmonary function (FEV1 = 98 ± 6% predicted) using 10% argon as a tracer gas and oxygen concentrations of 12.5%, 21%, or 90%. MBW was performed in accordance with ERS-ATS guidelines. Subjects initially inspired air followed by a wash-in of test gas. Tests were performed in balanced order in triplicate. Gas concentrations were measured at the mouth, and argon signals rescaled to mimic a N2 washout, and analyzed to determine the distribution of specific ventilation (SV). Heterogeneity was characterized by the width of a log-Gaussian fit of the SV distribution and from Sacin and Scond indexes derived from the phase III slope. There were no significant differences in the ventilation heterogeneity due to altered inspired oxygen: histogram width (hypoxia 0.57 ± 0.11, normoxia 0.60 ± 0.08, hyperoxia 0.59 ± 0.09, P = 0.51), Scond (hypoxia 0.014 ± 0.011, normoxia 0.012 ± 0.015, hyperoxia 0.010 ± 0.011, P = 0.34), or Sacin (hypoxia 0.11 ± 0.04, normoxia 0.10 ± 0.03, hyperoxia 0.12 ± 0.03, P = 0.23). Functional residual capacity was increased in hypoxia (P = 0.04) and dead space increased in hyperoxia (P = 0.0001) compared with the other conditions. The acute use of 100% oxygen in MBW or MRI is unlikely to affect ventilation heterogeneity. NEW & NOTEWORTHY Hyperoxia is used to measure the distribution of ventilation in imaging and MBW but may alter the underlying ventilation distribution. We used MBW to evaluate the effect of inspired oxygen concentration on the ventilation distribution using 10% argon as a tracer. Short-duration exposure to hypoxia (12.5% oxygen) and hyperoxia (90% oxygen) during MBW had no significant effect on ventilation heterogeneity, suggesting that hyperoxia can be used to assess the ventilation distribution. PMID:28280107

Ventilation heterogeneity measured by multiple breath inert gas testing is not affected by inspired oxygen concentration in healthy humans.

PubMed

Hopkins, Susan R; Elliott, Ann R; Prisk, G Kim; Darquenne, Chantal

2017-06-01

Multiple breath washout (MBW) and oxygen-enhanced MRI techniques use acute exposure to 100% oxygen to measure ventilation heterogeneity. Implicit is the assumption that breathing 100% oxygen does not induce changes in ventilation heterogeneity; however, this is untested. We hypothesized that ventilation heterogeneity decreases with increasing inspired oxygen concentration in healthy subjects. We performed MBW in 8 healthy subjects (4 women, 4 men; age = 43 ± 15 yr) with normal pulmonary function (FEV 1 = 98 ± 6% predicted) using 10% argon as a tracer gas and oxygen concentrations of 12.5%, 21%, or 90%. MBW was performed in accordance with ERS-ATS guidelines. Subjects initially inspired air followed by a wash-in of test gas. Tests were performed in balanced order in triplicate. Gas concentrations were measured at the mouth, and argon signals rescaled to mimic a N 2 washout, and analyzed to determine the distribution of specific ventilation (SV). Heterogeneity was characterized by the width of a log-Gaussian fit of the SV distribution and from S acin and S cond indexes derived from the phase III slope. There were no significant differences in the ventilation heterogeneity due to altered inspired oxygen: histogram width (hypoxia 0.57 ± 0.11, normoxia 0.60 ± 0.08, hyperoxia 0.59 ± 0.09, P = 0.51), S cond (hypoxia 0.014 ± 0.011, normoxia 0.012 ± 0.015, hyperoxia 0.010 ± 0.011, P = 0.34), or S acin (hypoxia 0.11 ± 0.04, normoxia 0.10 ± 0.03, hyperoxia 0.12 ± 0.03, P = 0.23). Functional residual capacity was increased in hypoxia ( P = 0.04) and dead space increased in hyperoxia ( P = 0.0001) compared with the other conditions. The acute use of 100% oxygen in MBW or MRI is unlikely to affect ventilation heterogeneity. NEW & NOTEWORTHY Hyperoxia is used to measure the distribution of ventilation in imaging and MBW but may alter the underlying ventilation distribution. We used MBW to evaluate the effect of inspired oxygen concentration on the ventilation distribution using 10% argon as a tracer. Short-duration exposure to hypoxia (12.5% oxygen) and hyperoxia (90% oxygen) during MBW had no significant effect on ventilation heterogeneity, suggesting that hyperoxia can be used to assess the ventilation distribution. Copyright © 2017 the American Physiological Society.

Spontaneous Breathing Trials and Conservative Sedation Practices Reduce Mechanical Ventilation Duration in Subjects With ARDS.

PubMed

Kallet, Richard H; Zhuo, Hanjing; Yip, Vivian; Gomez, Antonio; Lipnick, Michael S

2018-01-01

Spontaneous breathing trials (SBTs) and daily sedation interruptions (DSIs) reduce both the duration of mechanical ventilation and ICU length of stay (LOS). The impact of these practices in patients with ARDS has not previously been reported. We examined whether implementation of SBT/DSI protocols reduce duration of mechanical ventilation and ICU LOS in a retrospective group of subjects with ARDS at a large, urban, level-1 trauma center. All ARDS survivors from 2002 to 2016 ( N = 1,053) were partitioned into 2 groups: 397 in the pre-SBT/DSI group (June 2002-December 2007) and 656 in the post-SBT/DSI group (January 2009-April 2016). Patients from 2008, during the protocol implementation period, were excluded. An additional SBT protocol database (2008-2010) was used to assess the efficacy of SBT in transitioning subjects with ARDS to unassisted breathing. Comparisons were assessed by either unpaired t tests or Mann-Whitney tests. Multiple comparisons were made using either one-way analysis of variance or Kruskal-Wallis and Dunn's tests. Linear regression modeling was used to determine variables independently associated with mechanical ventilation duration and ICU LOS; differences were considered statistically significant when P < .05. Compared to the pre-protocol group, subjects with ARDS managed with SBT/DSI protocols experienced pronounced reductions both in median (IQR) mechanical ventilation duration (14 [6-29] vs 9 [4-17] d, respectively, P < .001) and median ICU LOS (18 [8-33] vs 13 [7-22] d, respectively P < .001). In the final model, only treatment in the SBT/DSI period and higher baseline respiratory system compliance were independently associated with reduced mechanical ventilation duration and ICU LOS. Among subjects with ARDS in the SBT performance database, most achieved unassisted breathing with a median of 2 SBTs. Evidenced-based protocols governing weaning and sedation practices were associated with both reduced mechanical ventilation duration and ICU LOS in subjects with ARDS. However, higher respiratory system compliance in the SBT/DSI cohort also contributed to these improved outcomes. Copyright © 2018 by Daedalus Enterprises.

Enhancing Safety of Artificially Ventilated Patients Using Ambient Process Analysis.

PubMed

Lins, Christian; Gerka, Alexander; Lüpkes, Christian; Röhrig, Rainer; Hein, Andreas

2018-01-01

In this paper, we present an approach for enhancing the safety of artificially ventilated patients using ambient process analysis. We propose to use an analysis system consisting of low-cost ambient sensors such as power sensor, RGB-D sensor, passage detector, and matrix infrared temperature sensor to reduce risks for artificially ventilated patients in both home and clinical environments. We describe the system concept and our implementation and show how the system can contribute to patient safety.

Exposure to noise during continuous positive airway pressure: influence of interfaces and delivery systems.

PubMed

Cavaliere, F; Conti, G; Costa, R; Spinazzola, G; Proietti, R; Sciuto, A; Masieri, S

2008-01-01

We measured noise intensity and perceived noisiness during continuous positive airway pressure (CPAP) performed with two interfaces (face-mask, helmet) and four delivery systems. Eight healthy volunteers received CPAP in random order with: two systems provided with a flow generator using the Venturi effect and a mechanical expiratory valve (A: Venturi, Starmed; B: Whisperflow-2, Caradyne Ltd); one 'free-flow' system provided with high flow O(2) and air flowmeters, an inspiratory gas reservoir, and a water valve (C: CF800, Drägerwerk, AG); and a standard mechanical ventilator (Servoventilator 300, Siemens-Elema). Systems A, B, and C were tested with a face-mask and a helmet at a CPAP value of 10 cm H(2)O; the mechanical ventilator was only tested with the face mask. Noise intensity was measured with a sound-level meter. After each test, participants scored noisiness on a visual analog scale (VAS). The noise levels measured ranged from 57+/-11 dBA (mechanical ventilator plus mask) to 93+/-1 and 94+/-2 dBA (systems A and B plus helmet) and were significantly affected by CPAP systems (A and B noisier than C and D) and interfaces (helmet CPAP noisier than mask CPAP). Subjective evaluation showed that systems A and B plus helmet were perceived as noisier than system C plus mask or helmet. Maximum noise levels observed in this study may potentially cause patient discomfort. Less noisy CPAP systems (not using Venturi effect) and interfaces (facial mask better than helmet) should be preferred, particularly for long or nocturnal treatments.

Variable versus conventional lung protective mechanical ventilation during open abdominal surgery: study protocol for a randomized controlled trial.

PubMed

Spieth, Peter M; Güldner, Andreas; Uhlig, Christopher; Bluth, Thomas; Kiss, Thomas; Schultz, Marcus J; Pelosi, Paolo; Koch, Thea; Gama de Abreu, Marcelo

2014-05-02

General anesthesia usually requires mechanical ventilation, which is traditionally accomplished with constant tidal volumes in volume- or pressure-controlled modes. Experimental studies suggest that the use of variable tidal volumes (variable ventilation) recruits lung tissue, improves pulmonary function and reduces systemic inflammatory response. However, it is currently not known whether patients undergoing open abdominal surgery might benefit from intraoperative variable ventilation. The PROtective VARiable ventilation trial ('PROVAR') is a single center, randomized controlled trial enrolling 50 patients who are planning for open abdominal surgery expected to last longer than 3 hours. PROVAR compares conventional (non-variable) lung protective ventilation (CV) with variable lung protective ventilation (VV) regarding pulmonary function and inflammatory response. The primary endpoint of the study is the forced vital capacity on the first postoperative day. Secondary endpoints include further lung function tests, plasma cytokine levels, spatial distribution of ventilation assessed by means of electrical impedance tomography and postoperative pulmonary complications. We hypothesize that VV improves lung function and reduces systemic inflammatory response compared to CV in patients receiving mechanical ventilation during general anesthesia for open abdominal surgery longer than 3 hours. PROVAR is the first randomized controlled trial aiming at intra- and postoperative effects of VV on lung function. This study may help to define the role of VV during general anesthesia requiring mechanical ventilation. Clinicaltrials.gov NCT01683578 (registered on September 3 3012).

Factors controlling particle number concentration and size at metro stations

NASA Astrophysics Data System (ADS)

Reche, C.; Moreno, T.; Martins, V.; Minguillón, M. C.; Jones, T.; de Miguel, E.; Capdevila, M.; Centelles, S.; Querol, X.

2017-05-01

An extensive air quality campaign was performed at differently designed station platforms in the Barcelona metro system, aiming to investigate the factors governing airborne particle number (N) concentrations and their size distributions. The study of the daily trends of N concentrations by different size ranges shows that concentrations of N0.3-10 are closely related with the schedule of the metro service. Conversely, the hourly variation of N0.007-10 (mainly composed of ultrafine particles) could be partly governed by the entrance of particles from outdoor emissions through mechanical ventilation. Measurements under different ventilation settings at three metro platforms reveal that the effect on air quality linked to changes in the tunnel ventilation depends on the station design. Night-time maintenance works in tunnels are frequent activities in the metro system; and after intense prolonged works, these can result in higher N concentrations at platforms during the following metro operating hours (by up to 30%), this being especially evident for N1-10. Due to the complex mixture of factors controlling N, together with the differences in trends recorded for particles within different size ranges, developing an air quality strategy at metro systems is a great challenge. When compared to street-level urban particles concentrations, the priority in metro air quality should be dealing with particles coarser than 0.3 μm. In fact, the results suggest that at narrow platforms served by single-track tunnels the current forced tunnel ventilation during operating hours is less efficient in reducing coarse particles compared to fine.

Water content of delivered gases during non-invasive ventilation in healthy subjects.

PubMed

Lellouche, François; Maggiore, Salvatore Maurizio; Lyazidi, Aissam; Deye, Nicolas; Taillé, Solenne; Brochard, Laurent

2009-06-01

No clear recommendation exists concerning humidification during non-invasive ventilation (NIV) and high flow CPAP, and few hygrometric data are available. We measured hygrometry during NIV delivered to healthy subjects with different humidification strategies: heated humidifier (HH), heat and moisture exchanger, (HME) or no humidification (NoH). For each strategy, a turbine and an ICU ventilator were used with different FiO(2) settings, with and without leaks. During CPAP, two different HH and NoH were tested. Inspired gases hygrometry was measured, and comfort was assessed. On a bench, we also assessed the impact of ambient air temperature, ventilator temperature and minute ventilation on HH performances (with NIV settings). During NIV, with NoH, gas humidity was very low when an ICU ventilator was used (5 mgH(2)O/l), but equivalent to ambient air hygrometry with a turbine ventilator at minimal FiO(2) (13 mgH(2)O/l). HME and HH had comparable performances (25-30 mgH(2)O/l), but HME's effectiveness was reduced with leaks (15 mgH(2)O/l). HH performances were reduced by elevated ambient air and ventilator output temperatures. During CPAP, dry gases (5 mgH(2)O/l) were less tolerated than humidified gases. Gases humidified at 15 or 30 mgH(2)O/l were equally tolerated. This study provides data on the level of humidity delivered with different humidification strategies during NIV and CPAP. HH and HME provide gas with the highest water content. Comfort data suggest that levels above 15 mgH(2)O/l are well tolerated. In favorable conditions, HH and HMEs are capable of providing such values, even in the presence of leaks.

A GIS-based approach: Influence of the ventilation layout to the environmental conditions in an underground mine.

PubMed

Bascompta, Marc; Castañón, Ana María; Sanmiquel, Lluís; Oliva, Josep

2016-11-01

Gases such as CO, CO2 or NOx are constantly generated by the equipment in any underground mine and the ventilation layout can play an important role in keeping low concentrations in the working faces. Hence, a method able to control the workplace environment is crucial. This paper proposes a geographical information system (GIS) for such goal. The system created provides the necessary tools to manage and analyse an underground environment, connecting pollutants and temperatures with the ventilation characteristics over time. Data concerning the ventilation system, in a case study, has been taken every month since 2009 and integrated into the management system, which has quantified the gasses concentration throughout the mine due to the characteristics and evolution of the ventilation layout. Three different zones concerning CO, CO2, NOx and effective temperature have been found as well as some variations among workplaces within the same zone that suggest local airflow recirculations. The system proposed could be a useful tool to improve the workplace conditions and efficiency levels. Copyright © 2016 Elsevier Ltd. All rights reserved.

Investigation of turbine ventilator performance after added wind cup for room exhaust air applications

NASA Astrophysics Data System (ADS)

Harun, D.; Zulfadhli; Akhyar, H.

2018-05-01

The turbine ventilator is a wind turbine with a vertical axis that has a combined function of the wind turbine and a suction fan. In this study, the turbine ventilator modified by adding a wind cup on the top (cap) turbine ventilator. The purpose of this experiment is to investigated the effect of the addition of wind cup on the turbine ventilator. Turbine ventilator used is type v30 and wind cup with diameter 77 mm. The experiment was conducted using a triangular pentagon model space chamber which was cut off to place the ventilator turbine ventilation cup with a volume of 0.983 m3 (equivalent to 1 mm3). The results of this study indicate that at an average wind speed of 1.8 m/s, the rotation of the turbine produced without a wind cup is 60.6 rpm while with the addition of a wind cup in the turbine ventilator is 69 rpm. The average increase of rotation turbine after added win cup is 8.4 rpm and the efficiency improvement of turbine ventilator is 1.7 %.

Evaluation of a Shaker Dust Collector for Use in a Recirculating Ventilation System

PubMed Central

Sawvel, Russell A.; Park, Jae Hong; Anthony, T. Renée

2016-01-01

General ventilation with recirculated air may be cost-effective to control the concentration of low-toxicity, contaminants in workplaces with diffuse, dusty operations, such as in agriculture. Such systems are, however, rarely adopted with little evidence showing improved air quality and ability to operate under harsh conditions. The goal of this work was to examine the initial and long-term performance of a fabric-filter shaker dust collector (SDC) in laboratory tests and as deployed within a recirculating ventilation system in an agricultural building. In laboratory tests, collection efficiency and pressure drop were tracked over several filter loading cycles, and the recovery of filter capacity (pressure drop) from filter shaking was examined. Collection efficiencies of particles larger than 5 μm was high (>95%) even when the filter was pristine, showing effective collection of large particles that dominate inhalable concentrations typical of agricultural dusts. For respirable-sized particles, collection efficiencies were low when the filter was pristine (e.g., 27% for 1 μm) but much higher when a dust cake developed on the filter (>99% for all size particles), even after shaking (e.g., 90% for 1 μm). The first shake of a filter was observed to recovery a substantial fraction of filter capacity, with subsequent shakes providing little benefit. In field tests, the SDC performed effectively over a period of three months in winter when incorporated in a recirculating ventilation system of a swine farrowing room. Trends in collection efficiency and pressure drop with loading were similar to those observed in the laboratory with overall collection efficiencies high (>80%) when pressure drop exceeded 230 Pa, or 23% of the maximum loading recommended by the manufacturer. This work shows that the SDC can function effectively over the harsh winter in swine rearing operations. Together with findings of improved air quality in the farrowing room reported in a companion manuscript, this article provides evidence that an SDC represents a cost-effective solution to improve air quality in agricultural settings. PMID:25955507

[Thoracoscopic thymectomy with carbon dioxide insufflation in the mediastinum].

PubMed

Ferrero-Coloma, C; Navarro-Martinez, J; Bolufer, S; Rivera-Cogollos, M J; Alonso-García, F J; Tarí-Bas, M I

2015-02-01

The case is presented of a 71 year-old male, diagnosed with a thymoma. A thoracoscopic thymectomy was performed using the carbon dioxide insufflation technique in the mediastinum. During the procedure, while performing one-lung ventilation, the patient's respiration worsened. The contralateral lung had collapsed, as carbon dioxide was travelling from the mediastinum to the thorax through the opened pleura. Two-lung ventilation was decided upon, which clearly improved oxygenation in the arterial gases and airway pressures. Both pH and pCO2 stabilized. The surgical approach and the carbon dioxide technique were continued because 2-lung ventilation did not affect the surgical procedure. This technique has many serious complications and it should always be performed using 2-lung ventilation. Copyright © 2014 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

[Bronchoscopy in ventilated patients: full narcosis or local anesthesia?].

PubMed

Konrad, F; Wiedeck, H; Winter, H; Kilian, J

1990-04-01

In a prospective, randomised trial bronchoscopy was performed either in local anaesthesia (LA) or general anaesthesia, each on 15 ventilated patients. LA was carried out with oxybuprocain-hydrochloride 1% in repeated doses injected into the trachea and main bronchi, general anaesthesia with midazolam, piritramide and vecuronium bromide. Measurements were performed before, 3 minutes after induction of anaesthesia, immediately after bronchoscopy and 15 and 60 minutes after bronchoscopy. There was no effect on cardiocirculatory function during bronchoscopy in both groups, but we found a decrease in paO2 from 97 to 80 mmHg (median) after application of LA. Subsequent bronchoscopy did not significantly influence paO2. The present study shows that in ventilation patients undergoing fibreoptic bronchoscopy, the application of LA will usually result in a decline of arterial oxygen tension. This procedure should therefore only be performed if general anaesthesia is undesirable, as e.g. in patients being weaned from ventilation.

32 CFR 644.450 - Items excluded from usual restoration obligation.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., ventilators, and metal ceilings. (8) Structural steel or iron. (9) Fire escapes. (10) Heating systems. (11) Plumbing systems. (12) Ventilating systems and air conditioning systems. (13) Power plants. (14) Electric wiring. (15) Lighting fixtures (or replacement). (16) Sprinkler systems. (f) Settling or subsidence. (g...

32 CFR 644.450 - Items excluded from usual restoration obligation.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., ventilators, and metal ceilings. (8) Structural steel or iron. (9) Fire escapes. (10) Heating systems. (11) Plumbing systems. (12) Ventilating systems and air conditioning systems. (13) Power plants. (14) Electric wiring. (15) Lighting fixtures (or replacement). (16) Sprinkler systems. (f) Settling or subsidence. (g...

32 CFR 644.450 - Items excluded from usual restoration obligation.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., ventilators, and metal ceilings. (8) Structural steel or iron. (9) Fire escapes. (10) Heating systems. (11) Plumbing systems. (12) Ventilating systems and air conditioning systems. (13) Power plants. (14) Electric wiring. (15) Lighting fixtures (or replacement). (16) Sprinkler systems. (f) Settling or subsidence. (g...

Ventilation Transport Trade Study for Future Space Suit Life Support Systems

NASA Technical Reports Server (NTRS)

Kempf, Robert; Vogel, Matthew; Paul, Heather L.

2008-01-01

A new and advanced portable life support system (PLSS) for space suit surface exploration will require a durable, compact, and energy efficient system to transport the ventilation stream through the space suit. Current space suits used by NASA circulate the ventilation stream via a ball-bearing supported centrifugal fan. As NASA enters the design phase for the next generation PLSS, it is necessary to evaluate available technologies to determine what improvements can be made in mass, volume, power, and reliability for a ventilation transport system. Several air movement devices already designed for commercial, military, and space applications are optimized in these areas and could be adapted for EVA use. This paper summarizes the efforts to identify and compare the latest fan and bearing technologies to determine candidates for the next generation PLSS.

Outcome of Patients with Systemic Sclerosis in the Intensive Care Unit.

PubMed

Pène, Frédéric; Hissem, Tarik; Bérezné, Alice; Allanore, Yannick; Geri, Guillaume; Charpentier, Julien; Avouac, Jérôme; Guillevin, Loïc; Cariou, Alain; Chiche, Jean-Daniel; Mira, Jean-Paul; Mouthon, Luc

2015-08-01

Patients with systemic sclerosis (SSc) are prone to disease-specific or treatment-related life-threatening complications that may warrant intensive care unit (ICU) admission. We assessed the characteristics and current outcome of patients with SSc admitted to the ICU. We performed a single-center retrospective study over 6 years (November 2006-December 2012). All patients with SSc admitted to the ICU were enrolled. Short-term (in-ICU and in-hospital) and longterm (6-mo and 1-yr) mortality rates were studied, and the prognostic factors were analyzed. Forty-one patients with a median age of 50 years [interquartile range (IQR) 40-65] were included. Twenty-nine patients (72.5%) displayed diffuse cutaneous SSc. The time from diagnosis to ICU admission was 78 months (IQR 34-128). Twenty-eight patients (71.7%) previously had pulmonary fibrosis, and 12 (31.5%) had pulmonary hypertension. The main reason for ICU admission was acute respiratory failure in 27 patients (65.8%). Noninvasive ventilation was first attempted in 13 patients (31.7%) and was successful in 8 of them, whereas others required endotracheal intubation within 24 h. Altogether, 13 patients (31.7%) required endotracheal intubation and mechanical ventilation. The overall in-ICU, in-hospital, 6-month, and 1-year mortality rates were 31.8%, 39.0%, 46.4%, and 61.0%, respectively. Invasive mechanical ventilation was the worst prognostic factor, associated with an in-hospital mortality rate of 84.6%. This study provides reliable prognostic data in patients with SSc who required ICU admission. The devastating outcome of invasive mechanical ventilation in patients with SSc requires a reappraisal of indications for ICU admission and early identification of patients likely to benefit from noninvasive ventilation.

FLOW-i ventilator performance in the presence of a circle system leak.

PubMed

Lucangelo, Umberto; Ajčević, Miloš; Accardo, Agostino; Borelli, Massimo; Peratoner, Alberto; Comuzzi, Lucia; Zin, Walter A

2017-04-01

Recently, the FLOW-i anaesthesia ventilator was developed based on the SERVO-i intensive care ventilator. The aim of this study was to test the FLOW-i's tidal volume delivery in the presence of a leak in the breathing circuit. We ventilated a test lung model in volume-, pressure-, and pressure-regulated volume-controlled modes (VC, PC, and PRVC, respectively) with a FLOW-i. First, the circuit remained airtight and the ventilator was tested with fresh gas flows of 6, 1, and 0.3 L/min in VC, PC, and PRVC modes and facing 4 combinations of different resistive and elastic loads. Second, a fixed leak in the breathing circuit was introduced and the measurements repeated. In the airtight system, FLOW-i maintained tidal volume (VT) and circuit pressure at approximately the set values, independently of respiratory mode, load, or fresh gas flow. In the leaking circuit, set VT = 500 mL, FLOW-i delivered higher VTs in PC (about 460 mL) than in VC and PRVC, where VTs were substantially less than 500 mL. Interestingly, VT did not differ appreciably from 6 to 0.3 L/min of fresh air flow among the 3 ventilatory modes. In the absence of leakage, peak inspiratory pressures were similar, while they were 35-45 % smaller in PRVC and VC than in PC mode in the presence of leaks. In conclusion, FLOW-i maintained VT (down to fresh gas flows of 0.3 L/min) to 90 % of its preset value in PC mode, which was 4-5 times greater than in VC or PRVC modes.

Performance of Particulate Containment at Nanotechnology Workplaces

PubMed Central

Lo, Li-Ming; Tsai, Candace S.-J.; Dunn, Kevin H.; Hammond, Duane; Marlow, David; Topmiller, Jennifer; Ellenbecker, Michael

2015-01-01

The evaluation of engineering controls for the production or use of carbon nanotubes (CNTs) was investigated at two facilities. These controls assessments are necessary to evaluate the current status of control performance and to develop proper control strategies for these workplaces. The control systems evaluated in these studies included ventilated enclosures, exterior hoods, and exhaust filtration systems. Activity-based monitoring with direct-reading instruments and filter sampling for microscopy analysis were used to evaluate the effectiveness of control measures at study sites. Our study results showed that weighing CNTs inside the biological safety cabinet can have a 37% reduction on the particle concentration in the worker’s breathing zone, and produce a 42% lower area concentration outside the enclosure. The ventilated enclosures used to reduce fugitive emissions from the production furnaces exhibited good containment characteristics when closed, but they failed to contain emissions effectively when opened during product removal/harvesting. The exhaust filtration systems employed for exhausting these ventilated enclosures did not provide promised collection efficiencies for removing engineered nanomaterials from furnace exhaust. The exterior hoods were found to be a challenge for controlling emissions from machining nanocomposites: the downdraft hood effectively contained and removed particles released from the manual cutting process, but using the canopy hood for powered cutting of nanocomposites created 15%–20% higher ultrafine (<500 nm) particle concentrations at the source and at the worker’s breathing zone. The microscopy analysis showed that CNTs can only be found at production sources but not at the worker breathing zones during the tasks monitored. PMID:26705393

Phase-change wallboard and mechanical night ventilation in commercial buildings: Potential for HVAC system downsizing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stetiu, C.; Feustel, H.E.

1998-07-01

As thermal storage media, phase-change materials (PCMs) such as paraffin, eutectic salts, etc. offer an order-of-magnitude increase in thermal storage capacity, and their discharge is almost isothermal. By embedding PCMs in dypsum board, plaster, or other wall-covering materials, the building structure acquires latent storage properties. Structural elements containing PCMs can store large amounts of energy while maintaining the indoor temperature within a relatively narrow range. As heat storage takes place inside the building where the loads occur, rather than at a central exterior location, the internal loads are removed without the need for additional transport energy. Distributed latent storage canmore » thus be used to reduce the peak power demand of a building, downsize the cooling system, and/or switch to low-energy cooling sources. The authors used RADCOOL, a thermal building simulation program based on the finite difference approach, to numerically evaluate the thermal performance of PCM wallboard coupled with mechanical night ventilation in office buildings offers the opportunity for system downsizing in climates where the outside air temperature drops below 18 C at night. In climates where the outside air temperature remains above 19 C at night, the use of PCM wallboard should be coupled with discharge mechanisms other than mechanical night ventilation with outside air.« less

Assessment of Factors Related to Auto-PEEP.

PubMed

Natalini, Giuseppe; Tuzzo, Daniele; Rosano, Antonio; Testa, Marco; Grazioli, Michele; Pennestrì, Vincenzo; Amodeo, Guido; Marsilia, Paolo F; Tinnirello, Andrea; Berruto, Francesco; Fiorillo, Marialinda; Filippini, Matteo; Peratoner, Alberto; Minelli, Cosetta; Bernardini, Achille

2016-02-01

Previous physiological studies have identified factors that are involved in auto-PEEP generation. In our study, we examined how much auto-PEEP is generated from factors that are involved in its development. One hundred eighty-six subjects undergoing controlled mechanical ventilation with persistent expiratory flow at the beginning of each inspiration were enrolled in the study. Volume-controlled continuous mandatory ventilation with PEEP of 0 cm H2O was applied while maintaining the ventilator setting as chosen by the attending physician. End-expiratory and end-inspiratory airway occlusion maneuvers were performed to calculate respiratory mechanics, and tidal flow limitation was assessed by a maneuver of manual compression of the abdomen. The variable with the strongest effect on auto-PEEP was flow limitation, which was associated with an increase of 2.4 cm H2O in auto-PEEP values. Moreover, auto-PEEP values were directly related to resistance of the respiratory system and body mass index and inversely related to expiratory time/time constant. Variables that were associated with the breathing pattern (tidal volume, frequency minute ventilation, and expiratory time) did not show any relationship with auto-PEEP values. The risk of auto-PEEP ≥5 cm H2O was increased by flow limitation (adjusted odds ratio 17; 95% CI: 6-56.2), expiratory time/time constant ratio <1.85 (12.6; 4.7-39.6), respiratory system resistance >15 cm H2O/L s (3; 1.3-6.9), age >65 y (2.8; 1.2-6.5), and body mass index >26 kg/m(2) (2.6; 1.1-6.1). Flow limitation, expiratory time/time constant, resistance of the respiratory system, and obesity are the most important variables that affect auto-PEEP values. Frequency expiratory time, tidal volume, and minute ventilation were not independently associated with auto-PEEP. Therapeutic strategies aimed at reducing auto-PEEP and its adverse effects should be primarily oriented to the variables that mainly affect auto-PEEP values. Copyright © 2016 by Daedalus Enterprises.

Basic life support trained nurses ventilate more efficiently with laryngeal mask supreme than with facemask or laryngeal tube suction-disposable--a prospective, randomized clinical trial.

PubMed

Gruber, Elisabeth; Oberhammer, Rosmarie; Balkenhol, Karla; Strapazzon, Giacomo; Procter, Emily; Brugger, Hermann; Falk, Markus; Paal, Peter

2014-04-01

In some emergency situations resuscitation and ventilation may have to be performed by basic life support trained personnel, especially in rural areas where arrival of advanced life support teams can be delayed. The use of advanced airway devices such as endotracheal intubation has been deemphasized for basically-trained personnel, but it is unclear whether supraglottic airway devices are advisable over traditional mask-ventilation. In this prospective, randomized clinical single-centre trial we compared airway management and ventilation performed by nurses using facemask, laryngeal mask Supreme (LMA-S) and laryngeal tube suction-disposable (LTS-D). Basic life support trained nurses (n=20) received one-hour practical training with each device. ASA 1-2 patients scheduled for elective surgery were included (n=150). After induction of anaesthesia and neuromuscular block nurses had two 90-second attempts to manage the airway and ventilate the patient with volume-controlled ventilation. Ventilation failed in 34% of patients with facemask, 2% with LMA-S and 22% with LTS-D (P<0.001). In patients who could be ventilated successfully mean tidal volume was 240±210 ml with facemask, 470±120 ml with LMA-S and 470±140 ml with LTS-D (P<0.001). Leak pressure was lower with LMA-S (23.3±10.8 cm H2O, 95% CI 20.2-26.4) than with LTS-D (28.9±13.9 cm·H2O, 95% CI 24.4-33.4; P=0.047). After one hour of introductory training, nurses were able to use LMA-S more effectively than facemask and LTS-D. High ventilation failure rates with facemask and LTS-D may indicate that additional training is required to perform airway management adequately with these devices. High-level trials are needed to confirm these results in cardiac arrest patients. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Highlighting the importance of transitional ventilation regimes in the management of Mediterranean show caves (Nerja-Pintada system, southern Spain).

PubMed

Liñán, C; Del Rosal, Y; Carrasco, F; Vadillo, I; Benavente, J; Ojeda, L

2018-08-01

This study shows the utilization of the air CO 2 exhaled by a very high number of visitors in the Nerja Cave as both a tracer and an additional tool to precisely evaluate the air circulation through the entire karst system, which includes non-touristic passages, originally free of anthropogenic CO 2 . The analysis of the temporal - spatial evolution of the CO 2 content and other monitoring data measured from January 2015 to December 2016 in the Nerja-Pintada system, including air microbiological controls, has allowed us to define a new general ventilation model, of great interest for the conservation of the subterranean environment. During the annual cycle four different ventilation regimes and two ventilation modes (UAF-mode and DAF-mode) exist which determine the significance of the anthropogenic impact within the caves. During the winter regime, the strong ventilation regime and the airflow directions from the lowest to the highest entrance (UAF-mode) contribute to the rapid elimination of anthropogenic CO 2 , and this affects the whole karstic system. During the summer regime the DAF-mode ventilation (with airflows from the highest to the lowest entrances) is activated. Although the number of visitors is maximum and the natural ventilation of the karstic system is the lowest of the annual cycle, the anthropogenic impact only affects the Tourist Galleries. The transitional ventilation regimes -spring and autumn- are the most complex of the annual cycle, with changing air-flow directions (from UAF-mode to DAF-mode and vice versa) at diurnal and poly diurnal scale, which conditions the range of the anthropogenic impact in each sector of the karst system. The activation of the DAF-mode has been observed when the temperature difference between the external and air cave is higher than 5°C. Copyright © 2018 Elsevier B.V. All rights reserved.

Pretest Predictions for Ventilation Tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Y. Sun; H. Yang; H.N. Kalia

The objective of this calculation is to predict the temperatures of the ventilating air, waste package surface, concrete pipe walls, and insulation that will be developed during the ventilation tests involving various test conditions. The results will be used as input to the following three areas: (1) Decisions regarding testing set-up and performance. (2) Assessing how best to scale the test phenomena measured. (3) Validating numerical approach for modeling continuous ventilation. The scope of the calculation is to identify the physical mechanisms and parameters related to thermal response in the ventilation tests, and develop and describe numerical methods that canmore » be used to calculate the effects of continuous ventilation. Sensitivity studies to assess the impact of variation of linear power densities (linear heat loads) and ventilation air flow rates are included. The calculation is limited to thermal effect only.« less

Improving Patient Safety with X-Ray and Anesthesia Machine Ventilator Synchronization: A Medical Device Interoperability Case Study

NASA Astrophysics Data System (ADS)

Arney, David; Goldman, Julian M.; Whitehead, Susan F.; Lee, Insup

When a x-ray image is needed during surgery, clinicians may stop the anesthesia machine ventilator while the exposure is made. If the ventilator is not restarted promptly, the patient may experience severe complications. This paper explores the interconnection of a ventilator and simulated x-ray into a prototype plug-and-play medical device system. This work assists ongoing interoperability framework development standards efforts to develop functional and non-functional requirements and illustrates the potential patient safety benefits of interoperable medical device systems by implementing a solution to a clinical use case requiring interoperability.

An analysis of natural ventilation techniques to achieve indoor comfort in Wal-Mart express

NASA Astrophysics Data System (ADS)

O'Dea, Shona

Despite global efforts to reduce world fossil fuel dependency the world still obtains 81% of its energy from fossil fuels (IEA,2009). Modern renewable alternatives have been around since the mid twentieth century these alternatives have not been integrated into electrical grid systems at the exponential rate required to eradicate fossil fuels dependency. The problem, world energy demand, is too large to be satisfied by anything other than the energy-dense fossil fuels used today. We must change our energy intensive processes in order to conserve energy and hence reduce the demands that alternatives must satisfy. This research aims to identify sustainable design opportunities through the application of innovative technologies for the largest retailer in the US with the view that a viable conservative design measure could be applied to the store model, which is replicated across the country, causing a cumulative and hence larger impact on the company energy consumption as a whole. This paper will present the literature available on the 'big box' industry and Wal-Mart, comfort, natural ventilation and building simulation software and then perform an analysis into the viability of naturally ventilating the Wal-Mart Express sales zone using Monodraught natural ventilation windcatcher products

Chronic hypoventilation syndromes and sleep-related hypoventilation

PubMed Central

Böing, Sebastian

2015-01-01

Chronic hypoventilation affects patients with disorders on any level of the respiratory system. The generation of respiratory impulses can be impaired in congenital disorders, such as central congenital alveolar hypoventilation, in alterations of the brain stem or complex diseases like obesity hypoventilation. The translation of the impulses via spinal cord and nerves to the respiratory muscles can be impaired in neurological diseases. Thoraco-skeletal or muscular diseases may inhibit the execution of the impulses. All hypoventilation disorders are characterized by a reduction of the minute ventilation with an increase of daytime hypercapnia. As sleep reduces minute ventilation substantially in healthy persons and much more pronounced in patients with underlying thoraco-pulmonary diseases, hypoventilation manifests firstly during sleep. Therefore, sleep related hypoventilation may be an early stage of chronic hypoventilation disorders. After treatment of any prevailing underlying disease, symptomatic therapy with non-invasive ventilation (NIV) is required. The adaptation of the treatment should be performed under close medical supervision. Pressure support algorithms have become most frequently used. The most recent devices automatically apply pressure support and vary inspiratory and expiratory pressures and breathing frequency in order to stabilize upper airways, normalize ventilation, achieve best synchronicity between patient and device and aim at optimizing patients’ adherence. PMID:26380756

Collective fluid mechanics of honeybee nest ventilation

NASA Astrophysics Data System (ADS)

Gravish, Nick; Combes, Stacey; Wood, Robert J.; Peters, Jacob

2014-11-01

Honeybees thermoregulate their brood in the warm summer months by collectively fanning their wings and creating air flow through the nest. During nest ventilation workers flap their wings in close proximity in which wings continuously operate in unsteady oncoming flows (i.e. the wake of neighboring worker bees) and near the ground. The fluid mechanics of this collective aerodynamic phenomena are unstudied and may play an important role in the physiology of colony life. We have performed field and laboratory observations of the nest ventilation wing kinematics and air flow generated by individuals and groups of honeybee workers. Inspired from these field observations we describe here a robotic model system to study collective flapping wing aerodynamics. We microfabricate arrays of 1.4 cm long flapping wings and observe the air flow generated by arrays of two or more fanning robotic wings. We vary phase, frequency, and separation distance among wings and find that net output flow is enhanced when wings operate at the appropriate phase-distance relationship to catch shed vortices from neighboring wings. These results suggest that by varying position within the fanning array honeybee workers may benefit from collective aerodynamic interactions during nest ventilation.

TH-E-BRF-02: 4D-CT Ventilation Image-Based IMRT Plans Are Dosimetrically Comparable to SPECT Ventilation Image-Based Plans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kida, S; University of Tokyo Hospital, Bunkyo, Tokyo; Bal, M

Purpose: An emerging lung ventilation imaging method based on 4D-CT can be used in radiotherapy to selectively avoid irradiating highly-functional lung regions, which may reduce pulmonary toxicity. Efforts to validate 4DCT ventilation imaging have been focused on comparison with other imaging modalities including SPECT and xenon CT. The purpose of this study was to compare 4D-CT ventilation image-based functional IMRT plans with SPECT ventilation image-based plans as reference. Methods: 4D-CT and SPECT ventilation scans were acquired for five thoracic cancer patients in an IRB-approved prospective clinical trial. The ventilation images were created by quantitative analysis of regional volume changes (amore » surrogate for ventilation) using deformable image registration of the 4D-CT images. A pair of 4D-CT ventilation and SPECT ventilation image-based IMRT plans was created for each patient. Regional ventilation information was incorporated into lung dose-volume objectives for IMRT optimization by assigning different weights on a voxel-by-voxel basis. The objectives and constraints of the other structures in the plan were kept identical. The differences in the dose-volume metrics have been evaluated and tested by a paired t-test. SPECT ventilation was used to calculate the lung functional dose-volume metrics (i.e., mean dose, V20 and effective dose) for both 4D-CT ventilation image-based and SPECT ventilation image-based plans. Results: Overall there were no statistically significant differences in any dose-volume metrics between the 4D-CT and SPECT ventilation imagebased plans. For example, the average functional mean lung dose of the 4D-CT plans was 26.1±9.15 (Gy), which was comparable to 25.2±8.60 (Gy) of the SPECT plans (p = 0.89). For other critical organs and PTV, nonsignificant differences were found as well. Conclusion: This study has demonstrated that 4D-CT ventilation image-based functional IMRT plans are dosimetrically comparable to SPECT ventilation image-based plans, providing evidence to use 4D-CT ventilation imaging for clinical applications. Supported in part by Free to Breathe Young Investigator Research Grant and NIH/NCI R01 CA 093626. The authors thank Philips Radiation Oncology Systems for the Pinnacle3 treatment planning systems.« less

Assessing Thermal Comfort Due to a Ventilated Double Window

NASA Astrophysics Data System (ADS)

Carlos, Jorge S.; Corvacho, Helena

2017-10-01

Building design and its components are the result of a complex process, which should provide pleasant conditions to its inhabitants. Therefore, indoor acceptable comfort is influenced by the architectural design. ISO and ASHRAE standards define thermal comfort as the condition of mind that expresses satisfaction with the thermal environment. The energy demand for heating, beside the building’s physical properties, also depend on human behaviour, like opening or closing windows. Generally, windows are the weakest façade element concerning to thermal performance. A lower thermal resistance allows higher thermal conduction through it. When a window is very hot or cold, and the occupant is very close to it, it may result in thermal discomfort. The functionality of a ventilated double window introduces new physical considerations to a traditional window. In consequence, it is necessary to study the local effect on human comfort in function of the boundary conditions. Wind, solar availability, air temperature and therefore heating and indoor air quality conditions will affect the relationship between this passive system and the indoor environment. In the present paper, the influence of thermal performance and ventilation on human comfort resulting from the construction and geometry solutions is shown, helping to choose the best solution. The presented approach shows that in order to save energy it is possible to reduce the air changes of a room to the minimum, without compromising air quality, enhancing simultaneously local thermal performance and comfort. The results of the study on the effect of two parallel windows with a ventilated channel in the same fenestration on comfort conditions for several different room dimensions, are also presented. As the room dimensions’ rate changes so does the window to floor rate; therefore, under the same climatic conditions and same construction solution, different results are obtained.

Influence of drive and timing mechanisms on breathing pattern and ventilation during mental task performance.

PubMed

Wientjes, C J; Grossman, P; Gaillard, A W

1998-09-01

Assessment of multiple respiratory measures may provide insight into how behavioral demands affect the breathing pattern. This is illustrated by data from a study among 44 subjects, in which tidal volume, respiration rate, minute ventilation and indices of central drive and timing mechanisms were assessed via inductive plethysmography, in addition to end-tidal PCO2. After a baseline, three conditions of a memory comparison task were presented. The first two conditions differed only with regard to the presence or absence of feedback of performance (NFB and FB). In the third 'all-or-nothing' (AON) condition, subjects only received a monetary bonus, if their performance exceeded that of the previous two conditions. Minute ventilation increased from baseline to all task conditions, and from NFB and FB to AON. Respiration rate increased in all task conditions, but there were no differences between task conditions. Tidal volume decreased during NFB, but was equal to baseline during FB and AON. Of the respiratory control indices, inspiratory flow rate covaried much more closely with minute ventilation than duty cycle. The task performance induced a minor degree of hyperventilation. The discussion focusses on how behavioral demands affect respiratory control processes to produce alterations in breathing pattern and ventilation.

[Bellows or bag? Testing 10 ventilators and some medical history comments].

PubMed

Kötter, K P; Maleck, W H; Altmannsberger, S; Herchet, J; Petroianu, G A

1998-01-01

We compared a new bellows ventilator (Kendall Cardiovent) with two other bellows (Dräger Resutator 63, Tagg Breathsaver) and seven bag or ball ventilators (Aerodyne Hope, Ambu Mark 3, Ambu Silicon, Dräger Resutator 2000, Laerdal Resu, Mercury CPR, Weinmann Combibag). Tidal volumes were measured with two Laerdal Recording Resusci Annies, one lying on the floor, one in a bed. Twelve participants performed mask ventilation with all ten devices on both manikins for two minutes, trying to achieve tidal volumes of between 0.8 and 1.21 as recommended by the AHA. The last ten ventilations each on the graphic strips were analysed for volume. The participants scored handling of the devices on a 6-point scale (1 = very good, 6 = insufficient). The results of the Cardiovent were compared to those of the other devices by rank sum test (percentage of correct ventilations) and sign test (subjective handling). The Cardiovent provided exact ventilation with 95% of ventilations) on the floor and 78% of ventilations in bed in the recommended range. However, the percentage of correct ventilations with the Cardiovent was not significantly different to the other devices except for a lower percentage of correct ventilations with the Combibag in the in bed setting. Concerning subjective handling, the Cardiovent was significantly superior to several ball ventilators.

Airborne particle dispersion to an operating room environment during sliding and hinged door opening.

PubMed

Sadrizadeh, Sasan; Pantelic, Jovan; Sherman, Max; Clark, Jordan; Abouali, Omid

2018-03-08

Operating rooms (ORs) are usually over-pressurized in order to prevent the penetration of contaminated air and the consequent risk of surgical site infection. However, a door-opening can result in the rapid disappearance of pressure and contaminants can then easily penetrate into the surgical zone. Therefore, a broad knowledge and understanding of OR ventilation systems and their protective potential is essential for optimizing the surgical environment. This study investigated the air quality and level of airborne particles during a single and multiple door-opening cycles in an operating room supplied by a turbulent-mixing ventilation system. The exploration was carried out numerically using computational fluid dynamics. Model validation was performed to ensure the validity of the achieved results. The OR was initially over-pressurized by approximately 15Pa, relative to the adjacent corridors. Both sliding and hinged doors were simulated and compared. Penetration of bacteria carrying particles from the corridors to the OR can be successfully restricted by using a positive-pressure system. However, the results clearly indicate that frequent door opening can interfere with airflow ventilation systems, alter the pressure gradient, and increase the infection risk for the patient undergoing surgical intervention. Door-opening disturbs the airflow field and could result in containment failure. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

46 CFR 111.33-9 - Ventilation exhaust.

Code of Federal Regulations, 2010 CFR

2010-10-01

... REQUIREMENTS Power Semiconductor Rectifier Systems § 111.33-9 Ventilation exhaust. The exhaust of each forced-air semiconductor rectifier system must: (a) Terminate in a location other than a hazardous location...

Energy performance of a ventilation system for a block of apartments with a ground source heat pump as generation system

NASA Astrophysics Data System (ADS)

Lucchi, M.; Lorenzini, M.; Valdiserri, P.

2017-01-01

This work presents a numerical simulation of the annual performance of two different systems: a traditional one composed by a gas boiler-chiller pair and one consisting of a ground source heat pump (GSHP) both coupled to two thermal storage tanks. The systems serve a bloc of flats located in northern Italy and are assessed over a typical weather year, covering both the heating and cooling seasons. The air handling unit (AHU) coupled with the GSHP exhibits excellent characteristics in terms of temperature control, and has high performance parameters (EER and COP), which make conduction costs about 30% lower than those estimated for the traditional plant.

Testing of mechanical ventilators and infant incubators in healthcare institutions.

PubMed

Badnjevic, Almir; Gurbeta, Lejla; Jimenez, Elvira Ruiz; Iadanza, Ernesto

2017-01-01

The medical device industry has grown rapidly and incessantly over the past century. The sophistication and complexity of the designed instrumentation is nowadays rising and, with it, has also increased the need to develop some better, more effective and efficient maintenance processes, as part of the safety and performance requirements. This paper presents the results of performance tests conducted on 50 mechanical ventilators and 50 infant incubators used in various public healthcare institutions. Testing was conducted in accordance to safety and performance requirements stated in relevant international standards, directives and legal metrology policies. Testing of output parameters for mechanical ventilators was performed in 4 measuring points while testing of output parameters for infant incubators was performed in 7 measuring points for each infant incubator. As performance criteria, relative error of output parameters for mechanical ventilators and absolute error of output parameters for infant incubators was calculated. The ranges of permissible error, for both groups of devices, are regulated by the Rules on Metrological and Technical Requirements published in the Official Gazette of Bosnia and Herzegovina No. 75/14, which are defined based on international recommendations, standards and guidelines. All ventilators and incubators were tested by etalons calibrated in an ISO 17025 accredited laboratory, which provides compliance to international standards for all measured parameters.The results show that 30% of the tested medical devices are not operating properly and should be serviced, recalibrated and/or removed from daily application.

Adaptive support ventilation: State of the art review

PubMed Central

Fernández, Jaime; Miguelena, Dayra; Mulett, Hernando; Godoy, Javier; Martinón-Torres, Federico

2013-01-01

Mechanical ventilation is one of the most commonly applied interventions in intensive care units. Despite its life-saving role, it can be a risky procedure for the patient if not applied appropriately. To decrease risks, new ventilator modes continue to be developed in an attempt to improve patient outcomes. Advances in ventilator modes include closed-loop systems that facilitate ventilator manipulation of variables based on measured respiratory parameters. Adaptive support ventilation (ASV) is a positive pressure mode of mechanical ventilation that is closed-loop controlled, and automatically adjust based on the patient's requirements. In order to deliver safe and appropriate patient care, clinicians need to achieve a thorough understanding of this mode, including its effects on underlying respiratory mechanics. This article will discuss ASV while emphasizing appropriate ventilator settings, their advantages and disadvantages, their particular effects on oxygenation and ventilation, and the monitoring priorities for clinicians. PMID:23833471

Assessment of the impact of dipped guideways on urban rail transit systems: Ventilation and safety requirements

NASA Technical Reports Server (NTRS)

1982-01-01

The ventilation and fire safety requirements for subway tunnels with dipped profiles between stations as compared to subway tunnels with level profiles were evaluated. This evaluation is based upon computer simulations of a train fire emergency condition. Each of the tunnel configurations evaluated was developed from characteristics that are representative of modern transit systems. The results of the study indicate that: (1) The level tunnel system required about 10% more station cooling than dipped tunnel systems in order to meet design requirements; and (2) The emergency ventilation requirements are greater with dipped tunnel systems than with level tunnel systems.

Passive continuous positive airway pressure ventilation during cardiopulmonary resuscitation: a randomized cross-over manikin simulation study.

PubMed

Winkler, Bernd E; Muellenbach, Ralf M; Wurmb, Thomas; Struck, Manuel F; Roewer, Norbert; Kranke, Peter

2017-02-01

While controlled ventilation is most frequently used during cardiopulmonary resuscitation (CPR), the application of continuous positive airway pressure (CPAP) and passive ventilation of the lung synchronously with chest compressions and decompressions might represent a promising alternative approach. One benefit of CPAP during CPR is the reduction of peak airway pressures and therefore a potential enhancement in haemodynamics. We therefore evaluated the tidal volumes and airway pressures achieved during CPAP-CPR. During CPR with the LUCAS™ 2 compression device, a manikin model was passively ventilated at CPAP levels of 5, 10, 20 and 30 hPa with the Boussignac tracheal tube and the ventilators Evita ® V500, Medumat ® Transport, Oxylator ® EMX, Oxylog ® 2000, Oxylog ® 3000, Primus ® and Servo ® -i as well as the Wenoll ® diver rescue system. Tidal volumes and airway pressures during CPAP-CPR were recorded and analyzed. Tidal volumes during CPAP-CPR were higher than during compression-only CPR without positive airway pressure. The passively generated tidal volumes increased with increasing CPAP levels and were significantly influenced by the ventilators used. During ventilation at 20 hPa CPAP via a tracheal tube, the mean tidal volumes ranged from 125 ml (Medumat ® ) to 309 ml (Wenoll ® ) and the peak airway pressures from 23 hPa (Primus ® ) to 49 hPa (Oxylog ® 3000). Transport ventilators generated lower tidal volumes than intensive care ventilators or closed-circuit systems. Peak airway pressures during CPAP-CPR were lower than those during controlled ventilation CPR reported in literature. High peak airway pressures are known to limit the applicability of ventilation via facemask or via supraglottic airway devices and may adversely affect haemodynamics. Hence, the application of ventilators generating high tidal volumes with low peak airway pressures appears desirable during CPAP-CPR. The limited CPAP-CPR capabilities of transport ventilators in our study might be prerequisite for future developments of transport ventilators.

Novel analysis of 4DCT imaging quantifies progressive increases in anatomic dead space during mechanical ventilation in mice.

PubMed

Kim, Elizabeth H; Preissner, Melissa; Carnibella, Richard P; Samarage, Chaminda R; Bennett, Ellen; Diniz, Marcio A; Fouras, Andreas; Zosky, Graeme R; Jones, Heather D

2017-09-01

Increased dead space is an important prognostic marker in early acute respiratory distress syndrome (ARDS) that correlates with mortality. The cause of increased dead space in ARDS has largely been attributed to increased alveolar dead space due to ventilation/perfusion mismatching and shunt. We sought to determine whether anatomic dead space also increases in response to mechanical ventilation. Mice received intratracheal lipopolysaccharide (LPS) or saline and mechanical ventilation (MV). Four-dimensional computed tomography (4DCT) scans were performed at onset of MV and after 5 h of MV. Detailed measurements of airway volumes and lung tidal volumes were performed using image analysis software. The forced oscillation technique was used to obtain measures of airway resistance, tissue damping, and tissue elastance. The ratio of airway volumes to total tidal volume increased significantly in response to 5 h of mechanical ventilation, regardless of LPS exposure, and airways demonstrated significant variation in volumes over the respiratory cycle. These findings were associated with an increase in tissue elastance (decreased lung compliance) but without changes in tidal volumes. Airway volumes increased over time with exposure to mechanical ventilation without a concomitant increase in tidal volumes. These findings suggest that anatomic dead space fraction increases progressively with exposure to positive pressure ventilation and may represent a pathological process. NEW & NOTEWORTHY We demonstrate that anatomic dead space ventilation increases significantly over time in mice in response to mechanical ventilation. The novel functional lung-imaging techniques applied here yield sensitive measures of airway volumes that may have wide applications. Copyright © 2017 the American Physiological Society.

[Disinfectants and main sanitary and preventive measures for protection of ventilation and air-conditioning systems from Legionella contamination].

PubMed

Gerasimov, V N; Golov, E A; Khramov, M V; Diatlov, I A

2008-01-01

The study was devoted to selection and assessment of disinfecting preparations for prevention of contamination by Legionella. Using system of criteria for quality assessment of disinfectants, seven newdomestic ones belonging to quaternary ammonium compounds class or to oxygen-containing preparations and designed for disinfecting of air-conditioning and ventilation systems were selected. Antibacterial and disinfecting activities of working solutions of disinfectants were tested in laboratory on the test-surfaces and test-objects of premises' air-conditioning and ventilation systems contaminated with Legionella. High antimicrobial and disinfecting activity of new preparations "Dezactiv-M", "ExtraDez", "Emital-Garant", "Aquasept Plus", "Samarovka", "Freesept", and "Ecobreeze Oxy" during their exposure on objects and materials contaminated with Legionella was shown. Main sanitary and preventive measures for defending of air-conditioning and ventilation systems from contamination by Legionella species were presented.

Methane emissions and airflow patterns along longwall faces and through bleeder ventilation systems

PubMed Central

Schatzel, Steven J.; Dougherty, Heather N.

2015-01-01

The National Institute for Occupational Safety and Health (NIOSH) conducted an investigation of longwall face and bleeder ventilation systems using tracer gas experiments and computer network ventilation. The condition of gateroad entries, along with the caved material’s permeability and porosity changes as the longwall face advances, determine the resistance of the airflow pathways within the longwall’s worked-out area of the bleeder system. A series of field evaluations were conducted on a four-panel longwall district. Tracer gas was released at the mouth of the longwall section or on the longwall face and sampled at various locations in the gateroads inby the shield line. Measurements of arrival times and concentrations defined airflow/gas movements for the active/completed panels and the bleeder system, providing real field data to delineate these pathways. Results showed a sustained ability of the bleeder system to ventilate the longwall tailgate corner as the panels retreated. PMID:26925166

A gas flow indicator for portable life support systems

NASA Technical Reports Server (NTRS)

Bass, R. L., III; Schroeder, E. C.

1975-01-01

A three-part program was conducted to develop a gas flow indicator (GFI) to monitor ventilation flow in a portable life support system. The first program phase identified concepts which could potentially meet the GFI requirements. In the second phase, a working breadboard GFI, based on the concept of a pressure sensing diaphragm-aneroid assembly connected to a venturi, was constructed and tested. Extensive testing of the breadboard GFI indicated that the design would meet all NASA requirements including eliminating problems experienced with the ventilation flow sensor used in the Apollo program. In the third program phase, an optimized GFI was designed by utilizing test data obtained on the breadboard unit. A prototype unit was constructed using prototype materials and fabrication techniques, and performance tests indicated that the prototype GFI met or exceeded all requirements.

Experimental evaluation of the Skylab orbital workshop ventilation system concept

NASA Technical Reports Server (NTRS)

Allums, S. L.; Hastings, L. J.; Ralston, J. T.

1972-01-01

Extensive testing was conducted to evaluate the Orbital Workshop ventilation concept. Component tests were utilized to determine the relationship between operating characteristics at 1 and 0.34 atm. System tests were conducted at 1 atm within the Orbital Workshop full-scale mockup to assess delivered volumetric flow rate and compartment air velocities. Component tests with the Anemostat circular diffusers (plenum- and duct-mounted) demonstrated that the diffuser produced essentially equivalent airflow patterns and velocities in 1- and 0.34-atm environments. The tests also showed that the pressure drop across the diffuser could be scaled from 1 to 0.34 atm using the atmosphere pressure ratio. Fan tests indicated that the performance of a multiple, parallel-mounted fan cluster could be predicted by summing the single-fan flow rates at a given delta P.

A Turbine-Driven Ventilator Improves Adherence to Advanced Cardiac Life Support Guidelines During a Cardiopulmonary Resuscitation Simulation.

PubMed

Allen, Scott G; Brewer, Lara; Gillis, Erik S; Pace, Nathan L; Sakata, Derek J; Orr, Joseph A

2017-09-01

Research has shown that increased breathing frequency during cardiopulmonary resuscitation is inversely correlated with systolic blood pressure. Rescuers often hyperventilate during cardiopulmonary resuscitation (CPR). Current American Heart Association advanced cardiac life support recommends a ventilation rate of 8-10 breaths/min. We hypothesized that a small, turbine-driven ventilator would allow rescuers to adhere more closely to advanced cardiac life support (ACLS) guidelines. Twenty-four ACLS-certified health-care professionals were paired into groups of 2. Each team performed 4 randomized rounds of 2-min cycles of CPR on an intubated mannikin, with individuals altering between compressions and breaths. Two rounds of CPR were performed with a self-inflating bag, and 2 rounds were with the ventilator. The ventilator was set to deliver 8 breaths/min, pressure limit 22 cm H 2 O. Frequency, tidal volume (V T ), peak inspiratory pressure, and compression interruptions (hands-off time) were recorded. Data were analyzed with a linear mixed model and Welch 2-sample t test. The median (interquartile range [IQR]) frequency with the ventilator was 7.98 (7.98-7.99) breaths/min. Median (IQR) frequency with the self-inflating bag was 9.5 (8.2-10.7) breaths/min. Median (IQR) ventilator V T was 0.5 (0.5-0.5) L. Median (IQR) self-inflating bag V T was 0.6 (0.5-0.7) L. Median (IQR) ventilator peak inspiratory pressure was 22 (22-22) cm H 2 O. Median (IQR) self-inflating bag peak inspiratory pressure was 30 (27-35) cm H 2 O. Mean ± SD hands-off times for ventilator and self-inflating bag were 5.25 ± 2.11 and 6.41 ± 1.45 s, respectively. When compared with a ventilator, volunteers ventilated with a self-inflating bag within ACLS guidelines. However, volunteers ventilated with increased variation, at higher V T levels, and at higher peak pressures with the self-inflating bag. Hands-off time was also significantly lower with the ventilator. (ClinicalTrials.gov registration NCT02743299.). Copyright © 2017 by Daedalus Enterprises.

Time course of lung inflammatory and fibrogenic responses during protective mechanical ventilation in healthy rats.

PubMed

Krebs, Joerg; Pelosi, Paolo; Tsagogiorgas, Charalambos; Haas, Jenny; Yard, Benito; Rocco, Patricia R M; Luecke, Thomas

2011-09-15

This study aimed to assess pulmonary inflammatory and fibrogenic responses and their impact on lung mechanics and histology in healthy rats submitted to protective mechanical ventilation for different experimental periods. Eighteen Wistar rats were randomized to undergo open lung-mechanical ventilation (OL-MV) for 1, 6 or 12 h. Following a recruitment maneuver, a decremental PEEP trial was performed and PEEP set according to the minimal respiratory system static elastance. Respiratory system, lung, and chest-wall elastance and gas-exchange were maintained throughout the 12 h experimental period. Histological lung injury score remained low at 1 and 6 h, but was higher at 12 h due to overinflation. A moderate inflammatory response was observed with a distinct peak at 6h. Compared to unventilated controls, type I procollagen mRNA expression was decreased at 1 and 12h, while type III procollagen expression decreased throughout the 12h experimental period. In conclusion, OL-MV in healthy rats yielded overinflation after 6 h even though respiratory elastance and gas-exchange were preserved for up to 12 h. Copyright © 2011 Elsevier B.V. All rights reserved.

The necessity of HVAC system for the registered architectural cultural heritage building

NASA Astrophysics Data System (ADS)

Popovici, Cătălin George; Hudişteanu, Sebastian Valeriu; Cherecheş, Nelu-Cristian

2018-02-01

This study is intended to highlight the role of the ventilation and air conditioning system for a theatre. It was chosen as a case study the "Vasile Alecsandri" National Theatre of Jassy. The paper also sought to make a comparison in three distinct scenarios for HVAC Main Hall system - ventilation and air conditioning system of the Main Hall doesn't work; only the ventilation system of the Main Hall works and ventilation and air conditioning system of the Main Hall works. For analysing the comfort parameters, the ANSYS-Fluent software was used to build a 2D model of the building and simulation of HVAC system functionality during winter season, in all three scenarios. For the studied scenarios, the external conditions of Jassy and the indoor conditions of the theatre, when the entire spectacle hall is occupied were considered. The main aspects evaluated for each case were the air temperature, air velocity and relative humidity. The results are presented comparatively as plots and spectra of the interest parameters.

7. DETAIL, VENTILATION SYSTEM; EAST FRONT OF QUARANTINE GREENHOUSE #3 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. DETAIL, VENTILATION SYSTEM; EAST FRONT OF QUARANTINE GREENHOUSE #3 (BUILDING 31) - U.S. Plant Introduction Station, Quarantine Headhouses & Greenhouses, 11601 Old Pond Road, Glenn Dale, Prince George's County, MD

A ventilation intervention study in classrooms to improve indoor air quality: the FRESH study

PubMed Central

2013-01-01

Background Classroom ventilation rates often do not meet building standards, although it is considered to be important to improve indoor air quality. Poor indoor air quality is thought to influence both children’s health and performance. Poor ventilation in The Netherlands most often occurs in the heating season. To improve classroom ventilation a tailor made mechanical ventilation device was developed to improve outdoor air supply. This paper studies the effect of this intervention. Methods The FRESH study (Forced-ventilation Related Environmental School Health) was designed to investigate the effect of a CO2 controlled mechanical ventilation intervention on classroom CO2 levels using a longitudinal cross-over design. Target CO2 concentrations were 800 and 1200 parts per million (ppm), respectively. The study included 18 classrooms from 17 schools from the north-eastern part of The Netherlands, 12 experimental classrooms and 6 control classrooms. Data on indoor levels of CO2, temperature and relative humidity were collected during three consecutive weeks per school during the heating seasons of 2010–2012. Associations between the intervention and weekly average indoor CO2 levels, classroom temperature and relative humidity were assessed by means of mixed models with random school-effects. Results At baseline, mean CO2 concentration for all schools was 1335 ppm (range: 763–2000 ppm). The intervention was able to significantly decrease CO2 levels in the intervention classrooms (F (2,10) = 17.59, p < 0.001), with a mean decrease of 491 ppm. With the target set at 800 ppm, mean CO2 was 841 ppm (range: 743–925 ppm); with the target set at 1200 ppm, mean CO2 was 975 ppm (range: 887–1077 ppm). Conclusions Although the device was not capable of precisely achieving the two predefined levels of CO2, our study showed that classroom CO2 levels can be reduced by intervening on classroom ventilation using a CO2 controlled mechanical ventilation system. PMID:24345039

Effect of PEEP and Tidal Volume on Ventilation Distribution and End-Expiratory Lung Volume: A Prospective Experimental Animal and Pilot Clinical Study

PubMed Central

Becher, Tobias; Schädler, Dirk; Pulletz, Sven; Freitag-Wolf, Sandra; Weiler, Norbert; Frerichs, Inéz

2013-01-01

Introduction Lung-protective ventilation aims at using low tidal volumes (VT) at optimum positive end-expiratory pressures (PEEP). Optimum PEEP should recruit atelectatic lung regions and avoid tidal recruitment and end-inspiratory overinflation. We examined the effect of VT and PEEP on ventilation distribution, regional respiratory system compliance (CRS), and end-expiratory lung volume (EELV) in an animal model of acute lung injury (ALI) and patients with ARDS by using electrical impedance tomography (EIT) with the aim to assess tidal recruitment and overinflation. Methods EIT examinations were performed in 10 anaesthetized pigs with normal lungs ventilated at 5 and 10 ml/kg body weight VT and 5 cmH2O PEEP. After ALI induction, 10 ml/kg VT and 10 cmH2O PEEP were applied. Afterwards, PEEP was set according to the pressure-volume curve. Animals were randomized to either low or high VT ventilation changed after 30 minutes in a crossover design. Ventilation distribution, regional CRS and changes in EELV were analyzed. The same measures were determined in five ARDS patients examined during low and high VT ventilation (6 and 10 (8) ml/kg) at three PEEP levels. Results In healthy animals, high compared to low VT increased CRS and ventilation in dependent lung regions implying tidal recruitment. ALI reduced CRS and EELV in all regions without changing ventilation distribution. Pressure-volume curve-derived PEEP of 21±4 cmH2O (mean±SD) resulted in comparable increase in CRS in dependent and decrease in non-dependent regions at both VT. This implied that tidal recruitment was avoided but end-inspiratory overinflation was present irrespective of VT. In patients, regional CRS differences between low and high VT revealed high degree of tidal recruitment and low overinflation at 3±1 cmH2O PEEP. Tidal recruitment decreased at 10±1 cmH2O and was further reduced at 15±2 cmH2O PEEP. Conclusions Tidal recruitment and end-inspiratory overinflation can be assessed by EIT-based analysis of regional CRS. PMID:23991138

Thermal comfort in naturally ventilated and air-conditioned buildings in humid subtropical climate zone in China

NASA Astrophysics Data System (ADS)

Yang, Wei; Zhang, Guoqiang

2008-05-01

A thermal comfort field study has been carried out in five cities in the humid subtropical climate zone in China. The survey was performed in naturally ventilated and air-conditioned buildings during the summer season in 2006. There were 229 occupants from 111 buildings who participated in this study and 229 questionnaire responses were collected. Thermal acceptability assessment reveals that the indoor environment in naturally ventilated buildings could not meet the 80% acceptability criteria prescribed by ASHRAE Standard 55, and people tended to feel more comfortable in air-conditioned buildings with the air-conditioned occupants voting with higher acceptability (89%) than the naturally ventilated occupants (58%). The neutral temperatures in naturally ventilated and air-conditioned buildings were 28.3°C and 27.7°C, respectively. The range of accepted temperature in naturally ventilated buildings (25.0˜31.6°C) was wider than that in air-conditioned buildings (25.1˜30.3°C), which suggests that occupants in naturally ventilated buildings seemed to be more tolerant of higher temperatures. Preferred temperatures were 27.9°C and 27.3°C in naturally ventilated and air-conditioned buildings, respectively, both of which were 0.4°C cooler than neutral temperatures. This result suggests that people of hot climates may use words like “slightly cool” to describe their preferred thermal state. The relationship between draught sensation and indoor air velocity at different temperature ranges indicates that indoor air velocity had a significant influence over the occupants’ comfort sensation, and air velocities required by occupants increased with the increasing of operative temperatures. Thus, an effective way of natural ventilation which can create the preferred higher air movement is called for. Finally, the indoor set-point temperature of 26°C or even higher in air-conditioned buildings was confirmed as making people comfortable, which supports the regulation in China that in public and office buildings the set-point temperature of air-conditioning system should not be lower than 26°C.

Evaluation of Fractional Regional Ventilation Using 4D-CT and Effects of Breathing Maneuvers on Ventilation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mistry, Nilesh N., E-mail: nmistry@som.umaryland.edu; Diwanji, Tejan; Shi, Xiutao

2013-11-15

Purpose: Current implementations of methods based on Hounsfield units to evaluate regional lung ventilation do not directly incorporate tissue-based mass changes that occur over the respiratory cycle. To overcome this, we developed a 4-dimensional computed tomography (4D-CT)-based technique to evaluate fractional regional ventilation (FRV) that uses an individualized ratio of tidal volume to end-expiratory lung volume for each voxel. We further evaluated the effect of different breathing maneuvers on regional ventilation. The results from this work will help elucidate the relationship between global and regional lung function. Methods and Materials: Eight patients underwent 3 sets of 4D-CT scans during 1more » session using free-breathing, audiovisual guidance, and active breathing control. FRV was estimated using a density-based algorithm with mass correction. Internal validation between global and regional ventilation was performed by use of the imaging data collected during the use of active breathing control. The impact of breathing maneuvers on FRV was evaluated comparing the tidal volume from 3 breathing methods. Results: Internal validation through comparison between the global and regional changes in ventilation revealed a strong linear correlation (slope of 1.01, R{sup 2} of 0.97) between the measured global lung volume and the regional lung volume calculated by use of the “mass corrected” FRV. A linear relationship was established between the tidal volume measured with the automated breathing control system and FRV based on 4D-CT imaging. Consistently larger breathing volumes were observed when coached breathing techniques were used. Conclusions: The technique presented improves density-based evaluation of lung ventilation and establishes a link between global and regional lung ventilation volumes. Furthermore, the results obtained are comparable with those of other techniques of functional evaluation such as spirometry and hyperpolarized-gas magnetic resonance imaging. These results were demonstrated on retrospective analysis of patient data, and further research using prospective data is under way to validate this technique against established clinical tests.« less

Spacesuit Portable Life Support System Breadboard (PLSS 1.0) Development and Test Results

NASA Technical Reports Server (NTRS)

Watts, Carly A.; Vogel, Matt

2012-01-01

A multi-year effort has been carried out at the Johnson Space Center to develop an advanced EVA PLSS design intended to further the current state of the art by increasing operational flexibility, reducing consumables, and increasing robustness. This multi-year effort has culminated in the construction and operation of PLSS 1.0, a test rig that simulates full functionality of the advanced PLSS design. PLSS 1.0 integrates commercial off-the-shelf hardware with prototype technology development components, including the primary and secondary oxygen regulators, ventilation loop fan, Rapid Cycle Amine (RCA) swingbed, and Spacesuit Water Membrane Evaporator (SWME). PLSS 1.0 was tested from June 17th through September 30th, 2011. Testing accumulated 233 hours over 45 days, while executing 119 test points. An additional 164 hours of operational time were accrued during the test series, bringing the total operational time for PLSS 1.0 testing to 397 hours. Specific PLSS 1.0 test objectives assessed during this testing include: (1) Confirming prototype components perform in a system level test as they have performed during component level testing, (2) Identifying unexpected system-level interactions (3) Operating PLSS 1.0 in nominal steady-state EVA modes to baseline subsystem performance with respect to metabolic rate, ventilation loop pressure and flow rate, and environmental conditions (4) Simulating nominal transient EVA operational scenarios (5) Simulating contingency EVA operational scenarios (6) Further evaluating prototype technology development components Successful testing of the PLSS 1.0 provided a large database of test results that characterize system level and component performance. With the exception of several minor anomalies, the PLSS 1.0 test rig performed as expected. Documented anomalies and observations include: (1) Ventilation loop fan controller issues at high fan speeds (near 70,000 rpm, whereas the fan speed during nominal operations would be closer to 35,000 rpm) (2) RCA performance at boundary conditions, including carbon dioxide and water vapor saturation events, as well as reduced vacuum quality (3) SWME valve anomalies (4 documented cases where the SWME failed to respond to a control signal or physically jammed, preventing SWME control) (4) Reduction of SWME hollow fiber hydrophobicity and significant reduction of the SWME degassing capability after significant accumulated test time.

Ventilation/perfusion SPECT/CT in patients with pulmonary emphysema. Evaluation of software-based analysing.

PubMed

Schreiter, V; Steffen, I; Huebner, H; Bredow, J; Heimann, U; Kroencke, T J; Poellinger, A; Doellinger, F; Buchert, R; Hamm, B; Brenner, W; Schreiter, N F

2015-01-01

The purpose of this study was to evaluate the reproducibility of a new software based analysing system for ventilation/perfusion single-photon emission computed tomography/computed tomography (V/P SPECT/CT) in patients with pulmonary emphysema and to compare it to the visual interpretation. 19 patients (mean age: 68.1 years) with pulmonary emphysema who underwent V/P SPECT/CT were included. Data were analysed by two independent observers in visual interpretation (VI) and by software based analysis system (SBAS). SBAS PMOD version 3.4 (Technologies Ltd, Zurich, Switzerland) was used to assess counts and volume per lung lobe/per lung and to calculate the count density per lung, lobe ratio of counts and ratio of count density. VI was performed using a visual scale to assess the mean counts per lung lobe. Interobserver variability and association for SBAS and VI were analysed using Spearman's rho correlation coefficient. Interobserver agreement correlated highly in perfusion (rho: 0.982, 0.957, 0.90, 0.979) and ventilation (rho: 0.972, 0.924, 0.941, 0.936) for count/count density per lobe and ratio of counts/count density in SBAS. Interobserver agreement correlated clearly for perfusion (rho: 0.655) and weakly for ventilation (rho: 0.458) in VI. SBAS provides more reproducible measures than VI for the relative tracer uptake in V/P SPECT/CTs in patients with pulmonary emphysema. However, SBAS has to be improved for routine clinical use.

Trends in mechanical ventilation: are we ventilating our patients in the best possible way?

PubMed Central

Veneroni, Chiara; Farre’, Ramon

2017-01-01

This review addresses how the combination of physiology, medicine and engineering principles contributed to the development and advancement of mechanical ventilation, emphasising the most urgent needs for improvement and the most promising directions of future development. Several aspects of mechanical ventilation are introduced, highlighting on one side the importance of interdisciplinary research for further development and, on the other, the importance of training physicians sufficiently on the technological aspects of modern devices to exploit properly the great complexity and potentials of this treatment. Educational aims To learn how mechanical ventilation developed in recent decades and to provide a better understanding of the actual technology and practice. To learn how and why interdisciplinary research and competences are necessary for providing the best ventilation treatment to patients. To understand which are the most relevant technical limitations in modern mechanical ventilators that can affect their performance in delivery of the treatment. To better understand and classify ventilation modes. To learn the classification, benefits, drawbacks and future perspectives of automatic ventilation tailoring algorithms. PMID:28620428

The use of a modified technique to reduce radioactive air contamination in aerosol lung ventilation imaging.

PubMed

Avison, M; Hart, G

2001-06-01

The aim of this study was to reduce airborne contamination resulting from the use of aerosols in lung ventilation scintigraphy. Lung ventilation imaging is frequently performed with 99mTc-diethylenetriaminepentaacetate aerosol (DTPA), derived from a commercial nebuliser. Airborne contamination is a significant problem with this procedure; it results in exposure of staff to radiation and can reduce gamma camera performance when the ventilation is performed in the camera room. We examined the level of airborne contamination resulting from the standard technique with one of the most popular nebuliser kits and tested a modification which significantly reduced airborne contamination. Air contamination was measured while ventilating 122 patients. The modified technique reduced air contamination by a mean value of 64% (p = 0.028) compared with the standard control technique. Additionally, differences in contamination were examined when a mask or mouthpiece was used as well as differences between operators. A simplified method of monitoring air contamination is presented using a commonly available surface contamination monitor. The index so derived was proportional to air contamination (r = 0.88). The problems and regulations associated with airborne contamination are discussed.

Accidental entrapment of an endo-bronchial blocker tip by a surgical stapler during selective ventilation for lung lobectomy in a dog.

PubMed

Levionnois, Olivier L; Bergadano, Alessandra; Schatzmann, Urs

2006-01-01

To describe the use of an endobronchial blocker (EBB) and to perform selective ventilation during pulmonary lobe resection via thoracotomy in a dog and report its accidental stapling in the resection site. Clinical case report. One female dog with a suspected abscess or neoplasia of the right caudal pulmonary lobe. One-lung ventilation was performed using a wire-guided EBB to seal the contaminated parenchyma and facilitate surgical access. The affected lung parenchyma was resected and the resection site was closed with staples. Lobar resection was performed successfully, but the loop of the EBB guide wire was inadvertently entrapped in the staple line of the lobectomy. Staples were removed to release the wire loop, and the resulting air leak caused loss of ventilation control until the parenchyma was re-sealed. We recommend removing the wire guide associate with the EBB after successful lung separation to avoid accidents that could have life-threatening consequences if not recognized. One-lung ventilation is useful to isolate healthy parenchyma from diseased parenchyma during lobectomy. Anesthesiologists and surgeons need to be aware of the potential complications associated with use of EBB.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poppiti, James; Nelson, Roger; MacMillan, Walter J.

The Waste Isolation Pilot Plant (WIPP) is a 655-meter deep mine near Carlsbad, New Mexico, used to dispose the nation’s defense transuranic waste. Limited airborne radioactivity was released from a container of radioactive waste in WIPP on 14 February, 2014. As designed, a mine ventilation filtration system prevented the large scale release of contamination from the underground. However, isolation dampers leaked, which allowed the release of low levels of contaminants after the event until they were sealed. None of the exposed individuals received any recordable dose. While surface contamination was limited, contamination in the ventilation system and portions of themore » underground was substantial. High efficiency particulate air (HEPA) filters in the operating ventilation system ensure continued containment during recovery and resumption of disposal operations. However, ventilation flow is restricted since the incident, with all exhaust air directed through the filters. Decontamination and natural fixation by the hygroscopic nature of the salt host rock has reduced the likelihood of further contamination spread. Contamination control and ventilation system operability are crucial for resumption of operations. This article provides an operational assessment and evaluation of these two key areas.« less

Indoor Environmental Quality in Mechanically Ventilated, Energy-Efficient Buildings vs. Conventional Buildings.

PubMed

Wallner, Peter; Munoz, Ute; Tappler, Peter; Wanka, Anna; Kundi, Michael; Shelton, Janie F; Hutter, Hans-Peter

2015-11-06

Energy-efficient buildings need mechanical ventilation. However, there are concerns that inadequate mechanical ventilation may lead to impaired indoor air quality. Using a semi-experimental field study, we investigated if exposure of occupants of two types of buildings (mechanical vs. natural ventilation) differs with regard to indoor air pollutants and climate factors. We investigated living and bedrooms in 123 buildings (62 highly energy-efficient and 61 conventional buildings) built in the years 2010 to 2012 in Austria (mainly Vienna and Lower Austria). Measurements of indoor parameters (climate, chemical pollutants and biological contaminants) were conducted twice. In total, more than 3000 measurements were performed. Almost all indoor air quality and room climate parameters showed significantly better results in mechanically ventilated homes compared to those relying on ventilation from open windows and/or doors. This study does not support the hypothesis that occupants in mechanically ventilated low energy houses are exposed to lower indoor air quality.

Lung scintigraphy in differential diagnosis of peripheral lung cancer and community-acquired pneumonia

NASA Astrophysics Data System (ADS)

Krivonogov, Nikolay G.; Efimova, Nataliya Y.; Zavadovsky, Konstantin W.; Lishmanov, Yuri B.

2016-08-01

Ventilation/perfusion lung scintigraphy was performed in 39 patients with verified diagnosis of community-acquired pneumonia (CAP) and in 14 patients with peripheral lung cancer. Ventilation/perfusion ratio, apical-basal gradients of ventilation (U/L(V)) and lung perfusion (U/L(P)), and alveolar capillary permeability of radionuclide aerosol were determined based on scintigraphy data. The study demonstrated that main signs of CAP were increases in ventilation/perfusion ratio, perfusion and ventilation gradient on a side of the diseased lung, and two-side increase in alveolar capillary permeability rate for radionuclide aerosol. Unlike this, scintigraphic signs of peripheral lung cancer comprise an increase in ventilation/perfusion ratio over 1.0 on a side of the diseased lung with its simultaneous decrease on a contralateral side, normal values of perfusion and ventilation gradients of both lungs, and delayed alveolar capillary clearance in the diseased lung compared with the intact lung.

Lung scintigraphy in differential diagnosis of peripheral lung cancer and community-acquired pneumonia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krivonogov, Nikolay G., E-mail: kng@cardio-tomsk.ru; Efimova, Nataliya Y., E-mail: efimova@cardio-tomsk.ru; Zavadovsky, Konstantin W.

Ventilation/perfusion lung scintigraphy was performed in 39 patients with verified diagnosis of community-acquired pneumonia (CAP) and in 14 patients with peripheral lung cancer. Ventilation/perfusion ratio, apical-basal gradients of ventilation (U/L(V)) and lung perfusion (U/L(P)), and alveolar capillary permeability of radionuclide aerosol were determined based on scintigraphy data. The study demonstrated that main signs of CAP were increases in ventilation/perfusion ratio, perfusion and ventilation gradient on a side of the diseased lung, and two-side increase in alveolar capillary permeability rate for radionuclide aerosol. Unlike this, scintigraphic signs of peripheral lung cancer comprise an increase in ventilation/perfusion ratio over 1.0 on amore » side of the diseased lung with its simultaneous decrease on a contralateral side, normal values of perfusion and ventilation gradients of both lungs, and delayed alveolar capillary clearance in the diseased lung compared with the intact lung.« less

Effects of volatile and intravenous anesthesia on the alveolar and systemic inflammatory response in thoracic surgical patients.

PubMed

Schilling, Thomas; Kozian, Alf; Senturk, Mert; Huth, Christof; Reinhold, Annegret; Hedenstierna, Göran; Hachenberg, Thomas

2011-07-01

One-lung ventilation (OLV) results in alveolar proinflammatory effects, whereas their extent may depend on administration of anesthetic drugs. The current study evaluates the effects of different volatile anesthetics compared with an intravenous anesthetic and the relationship between pulmonary and systemic inflammation in patients undergoing open thoracic surgery. Sixty-three patients scheduled for elective open thoracic surgery were randomized to receive anesthesia with 4 mg · kg⁻¹ · h⁻¹ propofol (n = 21), 1 minimum alveolar concentration desflurane (n = 21), or 1 minimum alveolar concentration sevoflurane (n = 21). Analgesia was provided by remifentanil (0.25 μg · kg⁻¹ · min⁻¹). After intubation, all patients received pressure-controlled mechanical ventilation with a tidal volume of approximately 7 ml · kg ideal body weight, a peak airway pressure lower than 30 cm H₂O, a respiratory rate adjusted to a Paco2 of 40 mmHg, and a fraction of inspired oxygen lower than 0.8 during OLV. Fiberoptic bronchoalveolar lavage of the ventilated lung was performed immediately after intubation and after surgery. The expression of inflammatory cytokines was determined in the lavage fluids and serum samples by multiplexed bead-based immunoassays. Proinflammatory cytokines increased in the ventilated lung after OLV. Mediator release was more enhanced during propofol anesthesia compared with desflurane or sevoflurane administration. For tumor necrosis factor-α, the values were as follows: propofol, 5.7 (8.6); desflurane, 1.6 (0.6); and sevoflurane, 1.6 (0.7). For interleukin-8, the values were as follows: propofol, 924 (1680); desflurane, 390 (813); and sevoflurane, 412 (410). (Values are given as median [interquartile range] pg · ml⁻¹). Interleukin-1β was similarly reduced during volatile anesthesia. The postoperative serum interleukin-6 concentration was increased in all patients, whereas the systemic proinflammatory response was negligible. OLV increases the alveolar concentrations of proinflammatory mediators in the ventilated lung. Both desflurane and sevoflurane suppress the local alveolar, but not the systemic, inflammatory responses to OLV and thoracic surgery.

Energy efficiency buildings program

NASA Astrophysics Data System (ADS)

1981-05-01

Progress is reported in developing techniques for auditing the energy performance of buildings. The ventilation of buildings and indoor air quality is discussed from the viewpoint of (1) combustion generated pollutants; (2) organic contaminants; (3) radon emanation, measurements, and control; (4) strategies for the field monitoring of indoor air quality; and (5) mechanical ventilation systems using air-to-air heat exchanges. The development of energy efficient windows to provide optimum daylight with minimal thermal losses in cold weather and minimum thermal gain in hot weather is considered as well as the production of high frequency solid state ballasts for fluorescent lights to provide more efficient lighting at a 25% savings over conventional core ballasts. Data compilation, analysis, and demonstration activities are summarized.

Data on the natural ventilation performance of windcatcher with anti-short-circuit device (ASCD).

PubMed

Nejat, Payam; Calautit, John Kaiser; Majid, Muhd Zaimi Abd; Hughes, Ben Richard; Jomehzadeh, Fatemeh

2016-12-01

This article presents the datasets which were the results of the study explained in the research paper 'Anti-short-circuit device: a new solution for short-circuiting in windcatcher and improvement of natural ventilation performance' (P. Nejat, J.K. Calautit, M.Z. Abd. Majid, B.R. Hughes, F. Jomehzadeh, 2016) [1] which introduces a new technique to reduce or prevent short-circuiting in a two-sided windcatcher and also lowers the indoor CO2 concentration and improve the ventilation distribution. Here, we provide details of the numerical modeling set-up and data collection method to facilitate reproducibility. The datasets includes indoor airflow, ventilation rates and CO2 concentration data at several points in the flow field. The CAD geometry of the windcatcher models are also included.

The use of intermittent positive pressure ventilation to differentiate pneumonia from atelectasis during anesthesia in a red panda (Ailurus fulgens).

PubMed

Phair, Kristen; West, Gary; Biller, David

2010-12-01

Radiography is a valuable tool for assessment of pulmonary disease. Specifically, radiographs utilizing positive pressure ventilation can distinguish between anesthesia-induced atelectasis and pulmonary disease when survey radiographs are ambiguous. Positive pressure ventilation can be used to radiographically prove or disprove pulmonary disease. This is of particular clinical importance when working with exotic, zoo, or wildlife species because the majority of these patients require general anesthesia to perform physical examinations and diagnostics such as radiography safely and efficiently. This report is a case example of pulmonary disease in a red panda (Ailurus fulgens) and demonstrates how positive pressure ventilation verified both the presence of pulmonary disease and the eventual resolution of the disease. Anesthetized patients on gas anesthesia will rapidly become atelectic. Through the use of positive pressure ventilation, anesthesia-induced atelectasis and true pulmonary disease can readily be distinguished. This is a technique that should not be overlooked when performing thoracic radiography in zoo species.

Epidemiology of Noninvasive Ventilation in Pediatric Cardiac ICUs.

PubMed

Romans, Ryan A; Schwartz, Steven M; Costello, John M; Chanani, Nikhil K; Prodhan, Parthak; Gazit, Avihu Z; Smith, Andrew H; Cooper, David S; Alten, Jeffrey; Mistry, Kshitij P; Zhang, Wenying; Donohue, Janet E; Gaies, Michael

2017-10-01

To describe the epidemiology of noninvasive ventilation therapy for patients admitted to pediatric cardiac ICUs and to assess practice variation across hospitals. Retrospective cohort study using prospectively collected clinical registry data. Pediatric Cardiac Critical Care Consortium clinical registry. Patients admitted to cardiac ICUs at PC4 hospitals. None. We analyzed all cardiac ICU encounters that included any respiratory support from October 2013 to December 2015. Noninvasive ventilation therapy included high flow nasal cannula and positive airway pressure support. We compared patient and, when relevant, perioperative characteristics of those receiving noninvasive ventilation to all others. Subgroup analysis was performed on neonates and infants undergoing major cardiovascular surgery. To examine duration of respiratory support, we created a casemix-adjustment model and calculated adjusted mean durations of total respiratory support (mechanical ventilation + noninvasive ventilation), mechanical ventilation, and noninvasive ventilation. We compared adjusted duration of support across hospitals. The cohort included 8,940 encounters from 15 hospitals: 3,950 (44%) received noninvasive ventilation and 72% were neonates and infants. Medical encounters were more likely to include noninvasive ventilation than surgical. In surgical neonates and infants, 2,032 (55%) received postoperative noninvasive ventilation. Neonates, extracardiac anomalies, single ventricle, procedure complexity, preoperative respiratory support, mechanical ventilation duration, and postoperative disease severity were associated with noninvasive ventilation therapy (p < 0.001 for all). Across hospitals, noninvasive ventilation use ranged from 32% to 65%, and adjusted mean noninvasive ventilation duration ranged from 1 to 4 days (3-d observed mean). Duration of total adjusted respiratory support was more strongly correlated with duration of mechanical ventilation compared with noninvasive ventilation (Pearson r = 0.93 vs 0.71, respectively). Noninvasive ventilation use is common in cardiac ICUs, especially in patients admitted for medical conditions, infants, and those undergoing high complexity surgery. We observed wide variation in noninvasive ventilation use across hospitals, though the primary driver of total respiratory support time seems to be duration of mechanical ventilation.

Performance of ICU ventilators during noninvasive ventilation with large leaks in a total face mask: a bench study.

PubMed

Nakamura, Maria Aparecida Miyuki; Costa, Eduardo Leite Vieira; Carvalho, Carlos Roberto Ribeiro; Tucci, Mauro Roberto

2014-01-01

Discomfort and noncompliance with noninvasive ventilation (NIV) interfaces are obstacles to NIV success. Total face masks (TFMs) are considered to be a very comfortable NIV interface. However, due to their large internal volume and consequent increased CO2 rebreathing, their orifices allow proximal leaks to enhance CO2 elimination. The ventilators used in the ICU might not adequately compensate for such leakage. In this study, we attempted to determine whether ICU ventilators in NIV mode are suitable for use with a leaky TFM. This was a bench study carried out in a university research laboratory. Eight ICU ventilators equipped with NIV mode and one NIV ventilator were connected to a TFM with major leaks. All were tested at two positive end-expiratory pressure (PEEP) levels and three pressure support levels. The variables analyzed were ventilation trigger, cycling off, total leak, and pressurization. Of the eight ICU ventilators tested, four did not work (autotriggering or inappropriate turning off due to misdetection of disconnection); three worked with some problems (low PEEP or high cycling delay); and one worked properly. The majority of the ICU ventilators tested were not suitable for NIV with a leaky TFM.

A complete audit cycle to assess adherence to a lung protective ventilation strategy.

PubMed

Joynes, Emma; Dalay, Satinder; Patel, Jaimin M; Fayek, Samia

2014-11-01

There is clear evidence for the use of a protective ventilation protocol in patients with acute respiratory distress syndrome (ARDS). There is evidence to suggest that protective ventilation is beneficial in patients at risk of ARDS. A protective ventilation strategy was implemented on our intensive care unit in critical care patients who required mechanical ventilation for over 48 h, with and at risk for ARDS. A complete audit cycle was performed over 13 months to assess compliance with a safe ventilation protocol in intensive care. The ARDS network mechanical ventilation protocol was used as the standard for our protective ventilation strategy. This recommends ventilation with a tidal volume (V t) of 6 ml/kg of ideal body weight (IBW) and plateau airway pressure of ≤30 cm H2O. The initial audit failed to meet this standard with V t's of 9.5 ml/kg of IBW. Following the implementation of a ventilation strategy and an educational program, we demonstrate a significant improvement in practice with V t's of 6.6 ml/kg of IBW in the re-audit. This highlights the importance of simple interventions and continuous education in maintaining high standards of care.

Adherence to the items in a bundle for the prevention of ventilator-associated pneumonia.

PubMed

Sachetti, Amanda; Rech, Viviane; Dias, Alexandre Simões; Fontana, Caroline; Barbosa, Gilberto da Luz; Schlichting, Dionara

2014-01-01

To assess adherence to a ventilator care bundle in an intensive care unit and to determine the impact of adherence on the rates of ventilator-associated pneumonia. A total of 198 beds were assessed for 60 days using a checklist that consisted of the following items: bed head elevation to 30 to 45º; position of the humidifier filter; lack of fluid in the ventilator circuit; oral hygiene; cuff pressure; and physical therapy. Next, an educational lecture was delivered, and 235 beds were assessed for the following 60 days. Data were also collected on the incidence of ventilator-acquired pneumonia. Adherence to the following ventilator care bundle items increased: bed head elevation from 18.7% to 34.5%; lack of fluid in the ventilator circuit from 55.6% to 72.8%; oral hygiene from 48.5% to 77.8%; and cuff pressure from 29.8% to 51.5%. The incidence of ventilator-associated pneumonia was statistically similar before and after intervention (p=0.389). The educational intervention performed in this study increased the adherence to the ventilator care bundle, but the incidence of ventilator-associated pneumonia did not decrease in the small sample that was assessed.

Innovative ventilation system for animal anatomy laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lacey, D.R.; Smith, D.C.

1997-04-01

A unique ventilation system was designed and built to reduce formaldehyde fumes in the large animal anatomy lab at the Vet Medical Center at Cornell University. The laboratory includes four rooms totaling 5,500 ft{sup 2}. The main room has 2,300 ft{sup 2} and houses the laboratory where up to 60 students dissect as many as 12 horses at a time. Other rooms are a cold storage locker, an animal preparation room and a smaller lab for specialized instruction. The large animal anatomy laboratory has a history of air quality complaints despite a fairly high ventilation rate of over 10 airmore » changes/hour. The horses are embalmed, creating a voluminous source of formaldehyde and phenol vapors. Budget constraints and increasingly stringent exposure limits for formaldehyde presented a great challenge to design a ventilation system that yields acceptable air quality. The design solution included two innovative elements: air-to-air heat recovery, and focused ventilation.« less

Change-over natural and mechanical ventilation system energy consumption in single-family buildings

NASA Astrophysics Data System (ADS)

Kostka, Maria; Szulgowska-Zgrzywa, Małgorzata

2017-11-01

The parameters of the outside air in Poland cause that in winter it is reasonable to use a mechanical ventilation equipped with a heat recovery exchanger. The time of spring, autumn, summer evenings and nights are often characterized by the parameters of the air, which allow for a natural ventilation and reduce the electricity consumption. The article presents the possibilities of energy consumption reduction for three energy standards of buildings located in Poland, ventilated by a change-over hybrid system. The analysis was prepared on the assumption that the air-to-water heat pump is the heat source for the buildings.

Building Assessment Survey and Evaluation (BASE) Study: Summarized Data - Test Space HVAC Characteristics

EPA Pesticide Factsheets

Information on the characteristics of the heating, ventilation, and air conditioning (HVAC) system(s) in the entire BASE building including types of ventilation, equipment configurations, and operation and maintenance issues

ACHP | News | ACHP Issues Program Comment for GSA on Select Repairs and

Science.gov Websites

to windows, lighting, roofing, and heating, ventilating, and air-conditioning (HVAC) systems within Upgrades Windows Lighting Roofing Heating, Ventilation, and Air Conditioning (HVAC) Systems Updated March

SUBSURFACE VOLATIZATION AND VENTILATION SYSTEM (SVVS) - INNOVATIVE TECHNOLOGY REPORT

EPA Science Inventory

This report summarizes the findings associated with a Demonstration Test of Environmental Improvement Technologies’ (EIT) Subsurface Volatilization and Ventilation System (SVVS) process. The technology was evaluated under the EPA Superfund Innovative Technology Evaluation (SITE) ...

Sound attenuation of fiberglass lined ventilation ducts

NASA Astrophysics Data System (ADS)

Albright, Jacob

Sound attenuation is a crucial part of designing any HVAC system. Most ventilation systems are designed to be in areas occupied by one or more persons. If these systems do not adequately attenuate the sound of the supply fan, compressor, or any other source of sound, the affected area could be subject to an array of problems ranging from an annoying hum to a deafening howl. The goals of this project are to quantify the sound attenuation properties of fiberglass duct liner and to perform a regression analysis to develop equations to predict insertion loss values for both rectangular and round duct liners. The first goal was accomplished via insertion loss testing. The tests performed conformed to the ASTM E477 standard. Using the insertion loss test data, regression equations were developed to predict insertion loss values for rectangular ducts ranging in size from 12-in x 18-in to 48-in x 48-in in lengths ranging from 3ft to 30ft. Regression equations were also developed to predict insertion loss values for round ducts ranging in diameters from 12-in to 48-in in lengths ranging from 3ft to 30ft.

Performance characteristics of axisymmetric convergent-divergent exhaust nozzles with longitudinal slots in the divergent

NASA Technical Reports Server (NTRS)

Leavitt, L. D.; Bangert, L. S.

1982-01-01

An investigation was conducted in the Langley 16 foot Transonic Tunnel and in the static test facility of that tunnel to determine the effects of divergent flap ventilation of an axisymmetric nozzle on nozzle internal (static) and wind on performance. Tests were conducted at 0 deg angle of attack at static conditions and at Mach numbers from 0.6 to 1.2. Ratios of jet total pressure to free stream static pressure were varied from 1.0 (jet off) to approximately 14.0 depending on Mach number. The results of this study indicate that divergent flap ventilation generally provided large performance benefits at overexpanded nozzle conditions and performance reductions at underexpanded nozzle conditions when compared to the baseline (unventilated) nozzles. Ventilation also reduced the peak static and wind on performance levels.

46 CFR 154.1205 - Mechanical ventilation system: Standards.

Code of Federal Regulations, 2013 CFR

2013-10-01

... operational controls outside the ventilated space. (g) No ventilation duct for a gas-dangerous space may pass... Section 154.1205 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and...

46 CFR 154.1205 - Mechanical ventilation system: Standards.

Code of Federal Regulations, 2014 CFR

2014-10-01

... operational controls outside the ventilated space. (g) No ventilation duct for a gas-dangerous space may pass... Section 154.1205 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and...

46 CFR 154.1205 - Mechanical ventilation system: Standards.

Code of Federal Regulations, 2012 CFR

2012-10-01

... operational controls outside the ventilated space. (g) No ventilation duct for a gas-dangerous space may pass... Section 154.1205 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and...

Respiratory mechanics in brain injury: A review.

PubMed

Koutsoukou, Antonia; Katsiari, Maria; Orfanos, Stylianos E; Kotanidou, Anastasia; Daganou, Maria; Kyriakopoulou, Magdalini; Koulouris, Nikolaos G; Rovina, Nikoletta

2016-02-04

Several clinical and experimental studies have shown that lung injury occurs shortly after brain damage. The responsible mechanisms involve neurogenic pulmonary edema, inflammation, the harmful action of neurotransmitters, or autonomic system dysfunction. Mechanical ventilation, an essential component of life support in brain-damaged patients (BD), may be an additional traumatic factor to the already injured or susceptible to injury lungs of these patients thus worsening lung injury, in case that non lung protective ventilator settings are applied. Measurement of respiratory mechanics in BD patients, as well as assessment of their evolution during mechanical ventilation, may lead to preclinical lung injury detection early enough, allowing thus the selection of the appropriate ventilator settings to avoid ventilator-induced lung injury. The aim of this review is to explore the mechanical properties of the respiratory system in BD patients along with the underlying mechanisms, and to translate the evidence of animal and clinical studies into therapeutic implications regarding the mechanical ventilation of these critically ill patients.

Experimental research on the indoor temperature and humidity fields in radiant ceiling air-conditioning system under natural ventilation

NASA Astrophysics Data System (ADS)

Huang, Tao; Xiang, Yutong; Wang, Yonghong

2017-05-01

In this paper, the indoor temperature and humidity fields of the air in a metal ceiling radiant panel air conditioning system with fresh air under natural ventilation were researched. The temperature and humidity distributions at different height and different position were compared. Through the computation analysis of partial pressure of water vapor, the self-recovery characteristics of humidity after the natural ventilation was discussed.

Alternatives generation and analysis for double-shell tank primary ventilation systems emissions control and monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

SEDERBURG, J.P.

1999-09-30

This AGA addresses the question: ''What equipment upgrades, operational changes, and/or other actions are required relative to the DST tanks farms' ventilation systems to support retrieval, staging (including feed sampling), and delivery of tank waste to the Phase I private contractor?'' Issues and options for the various components within the ventilation subsystem affect each other. Recommended design requirements are presented and the preferred alternatives are detailed.

Study of Alternate Material for Pedal Ventilator Kits.

DTIC Science & Technology

1980-04-01

to fans with diameters of 36 inches or less, revealed that a shelter ventilation system of minimum cost would require three units with 36-inch...doorways, it was decided, with OCD approval, to develop pre-assembled one and two-operator bicycle ventilator kits utilizing a fan and ducting system of...polypropylene matrix. According to Ford Motor Company, an enthusiastic user, this material hybrid offers large potential savings in direct substitution for glass

Effect of a ceiling fan ventilation system on finishing young bulls' health, behaviour and growth performance.

PubMed

Magrin, L; Brscic, M; Lora, I; Rumor, C; Tondello, L; Cozzi, G; Gottardo, F

2017-06-01

This research aimed at assessing the effects of a ceiling fan ventilation system on health, feeding, social behaviour and growth response of finishing young bulls fattened indoors during a mild summer season. A total of 69 Charolais young bulls were housed in six pens without any mechanical ventilation system (Control) and in six pens equipped with ceiling fans. The experimental period lasted 98 days from June until mid-September 2014. Four experimental days were considered in order to assess the effect of the ventilation system under two different microclimatic conditions: 2 alert days at monthly interval with temperature humidity index (THI) between 75 and 78, and 2 normal days with THI⩽74. Health and behaviour of the bulls were evaluated through 8-h observation sessions starting after morning feed delivery. The study was carried out during a rather cool summer with a climate average THI of 68.9 and 4 days with average THI>75. Despite these mild climate conditions, ceiling fans lowered litter moisture and acted as a preventive measure for bulls' dirtiness (odd ratio=47.9; 95% CI 19.6 to 117.4). The risk of abnormal breathing was increased for Control bulls (odd ratio=40.7; 95% CI 5.4 to 304.2). When exposed to alert THI conditions, respiration rate and panting scores increased and rumination duration dropped in Control bulls compared with bulls provided with a ceiling fan. During observations under alert THI, bulls spent less time eating, more time being inactive and consumed more water compared with normal THI conditions. Bulls' daily dry matter intake measured during the observation sessions decreased on alert compared with normal THI days (P<0.001) due to a drop of intake during the daylight hours. Ceiling fan treatment had no effect on bulls' growth performance or water consumption but these results most likely depended on the mild climate conditions. Ceiling fans proved to mitigate some of the negative effects of heat stress on bulls' behaviour (rumination, lying down and drinking water) and respiration rate, however. The lack of a significant improvement of bulls' growth response should not discourage beef farmers from using ceiling fans in indoor systems, considering the likely increase in frequency and intensity of heat waves in the planet's temperate areas induced by global warming.

Water spray ventilator system for continuous mining machines

DOEpatents

Page, Steven J.; Mal, Thomas

1995-01-01

The invention relates to a water spray ventilator system mounted on a continuous mining machine to streamline airflow and provide effective face ventilation of both respirable dust and methane in underground coal mines. This system has two side spray nozzles mounted one on each side of the mining machine and six spray nozzles disposed on a manifold mounted to the underside of the machine boom. The six spray nozzles are angularly and laterally oriented on the manifold so as to provide non-overlapping spray patterns along the length of the cutter drum.

[Non-invasive mechanical ventilation with a facial interface during sedation for a percutaneous endoscopic gastrostomy in a patient with amyotrophic lateral sclerosis].

PubMed

González-Frasquet, M C; García-Covisa, N; Vidagany-Espert, L; Herranz-Gordo, A; Llopis-Calatayud, J E

2015-11-01

Amyotrophic lateral sclerosis is a chronic neurodegenerative disease of the central nervous system which affects the motor neurons and produces a progressive muscle weakness, leading to atrophy and muscle paralysis, and ultimately death. Performing a percutaneous endoscopic gastrostomy with sedation in patients with amyotrophic lateral sclerosis can be a challenge for the anesthesiologist. The case is presented of a 76-year-old patient who suffered from advanced stage amyotrophic lateral sclerosis, ASA III, in which a percutaneous endoscopic gastrostomy was performed with deep sedation, for which non-invasive ventilation was used as a respiratory support to prevent hypoventilation and postoperative respiratory complications. Copyright © 2014 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

WE-AB-202-08: Feasibility of Single-Inhalation/Single-Energy Xenon CT for High-Resolution Imaging of Regional Lung Ventilation in Humans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pinkham, D; Schueler, E; Diehn, M

Purpose: To demonstrate the efficacy of a novel functional lung imaging method that utilizes single-inhalation, single-energy xenon CT (Xe-CT) lung ventilation scans, and to compare it against the current clinical standard, ventilation single-photon emission CT (V-SPECT). Methods: In an IRB-approved clinical study, 14 patients undergoing thoracic radiotherapy received two successive single inhalation, single energy (80keV) CT images of the entire lung using 100% oxygen and a 70%/30% xenon-oxygen mixture. A subset of ten patients also received concurrent SPECT ventilation scans. Anatomic reproducibility between the two scans was achieved using a custom video biofeedback apparatus. The CT images were registered tomore » each other by deformable registration, and a calculated difference image served as surrogate xenon ventilation map. Both lungs were partitioned into twelve sectors, and a sector-wise correlation was performed between the xenon and V-SPECT scans. A linear regression model was developed with forced expiratory volume (FEV) as a predictor and the coefficient of variation (CoV) as the outcome. Results: The ventilation comparison for five of the patients had either moderate to strong Pearson correlation coefficients (0.47 to 0.69, p<0.05). Of these, four also had moderate to strong Spearman correlation coefficients (0.46 to 0.80, p<0.03). The patients with the strongest correlation had clear regional ventilation deficits. The patient comparisons with the weakest correlations had more homogeneous ventilation distributions, and those patients also had diminished lung function as assessed by spirometry. Analysis of the relationship between CoV and FEV yielded a non-significant trend toward negative correlation (Pearson coefficient −0.60, p<0.15). Conclusion: Significant correlations were found between the Xe-CT and V-SPECT ventilation imagery. The results from this small cohort of patients indicate that single inhalation, single energy Xe-CT has the potential to quantify regional lung ventilation volumetrically with high resolution using widely accessible radiologic equipment. Bill Loo and Peter Maxim are founders of TibaRay, Inc. Bill Loo is also a board member. Bill Loo and Peter Maxim have received research grants from Varian Medical Systems, Inc. and RaySearch Laboratory.« less

29 CFR 1926.62 - Lead.

Code of Federal Regulations, 2013 CFR

2013-07-01

... annually to reflect the current status of the program. (3) Mechanical ventilation. When ventilation is used... potentially harmful effects of exposure to lead. (vii)(A) The employer shall ensure that the containers of... remove lead from any surface unless the compressed air is used in conjunction with a ventilation system...

29 CFR 1926.62 - Lead.

Code of Federal Regulations, 2012 CFR

2012-07-01

... annually to reflect the current status of the program. (3) Mechanical ventilation. When ventilation is used... potentially harmful effects of exposure to lead. (vii)(A) The employer shall ensure that the containers of... remove lead from any surface unless the compressed air is used in conjunction with a ventilation system...

29 CFR 1926.62 - Lead.

Code of Federal Regulations, 2010 CFR

2010-07-01

... annually to reflect the current status of the program. (3) Mechanical ventilation. When ventilation is used... potentially harmful effects of exposure to lead. (vii) The employer shall assure that the containers of... remove lead from any surface unless the compressed air is used in conjunction with a ventilation system...

29 CFR 1926.62 - Lead.

Code of Federal Regulations, 2014 CFR

2014-07-01

... annually to reflect the current status of the program. (3) Mechanical ventilation. When ventilation is used... potentially harmful effects of exposure to lead. (vii)(A) The employer shall ensure that the containers of... remove lead from any surface unless the compressed air is used in conjunction with a ventilation system...

29 CFR 1926.62 - Lead.

Code of Federal Regulations, 2011 CFR

2011-07-01

... annually to reflect the current status of the program. (3) Mechanical ventilation. When ventilation is used... potentially harmful effects of exposure to lead. (vii) The employer shall assure that the containers of... remove lead from any surface unless the compressed air is used in conjunction with a ventilation system...

Worsening respiratory function in mechanically ventilated intensive care patients: feasibility and value of xenon-enhanced dual energy CT.

PubMed

Hoegl, Sandra; Meinel, Felix G; Thieme, Sven F; Johnson, Thorsten R C; Eickelberg, Oliver; Zwissler, Bernhard; Nikolaou, Konstantin

2013-03-01

To evaluate the feasibility and incremental diagnostic value of xenon-enhanced dual-energy CT in mechanically ventilated intensive care patients with worsening respiratory function. The study was performed in 13 mechanically ventilated patients with severe pulmonary conditions (acute respiratory distress syndrome (ARDS), n=5; status post lung transplantation, n=5; other, n=3) and declining respiratory function. CT scans were performed using a dual-source CT scanner at an expiratory xenon concentration of 30%. Both ventilation images (Xe-DECT) and standard CT images were reconstructed from a single CT scan. Findings were recorded for Xe-DECT and standard CT images separately. Ventilation defects on xenon images were matched to morphological findings on standard CT images and incremental diagnostic information of xenon ventilation images was recorded if present. Mean xenon consumption was 2.95 l per patient. No adverse events occurred under xenon inhalation. In the visual CT analysis, the Xe-DECT ventilation defects matched with pathologic changes in lung parenchyma seen in the standard CT images in all patients. Xe-DECT provided additional diagnostic findings in 4/13 patients. These included preserved ventilation despite early pneumonia (n=1), more confident discrimination between a large bulla and pneumothorax (n=1), detection of an airway-to-pneumothorax fistula (n=1) and exclusion of a suspected airway-to-mediastinum fistula (n=1). In all 4 patients, the additional findings had a substantial impact on patients' management. Xenon-enhanced DECT is safely feasible and can add relevant diagnostic information in mechanically ventilated intensive care patients with worsening respiratory function. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

A new global and comprehensive model for ICU ventilator performances evaluation.

PubMed

Marjanovic, Nicolas S; De Simone, Agathe; Jegou, Guillaume; L'Her, Erwan

2017-12-01

This study aimed to provide a new global and comprehensive evaluation of recent ICU ventilators taking into account both technical performances and ergonomics. Six recent ICU ventilators were evaluated. Technical performances were assessed under two FIO 2 levels (100%, 50%), three respiratory mechanics combinations (Normal: compliance [C] = 70 mL cmH 2 O -1 /resistance [R] = 5 cmH 2 O L -1  s -1 ; Restrictive: C = 30/R = 10; Obstructive: C = 120/R = 20), four exponential levels of leaks (from 0 to 12.5 L min -1 ) and three levels of inspiratory effort (P0.1 = 2, 4 and 8 cmH 2 O), using an automated test lung. Ergonomics were evaluated by 20 ICU physicians using a global and comprehensive model involving physiological response to stress measurements (heart rate, respiratory rate, tidal volume variability and eye tracking), psycho-cognitive scales (SUS and NASA-TLX) and objective tasks completion. Few differences in terms of technical performance were observed between devices. Non-invasive ventilation modes had a huge influence on asynchrony occurrence. Using our global model, either objective tasks completion, psycho-cognitive scales and/or physiological measurements were able to depict significant differences in terms of devices' usability. The level of failure that was observed with some devices depicted the lack of adaptation of device's development to end users' requests. Despite similar technical performance, some ICU ventilators exhibit low ergonomics performance and a high risk of misusage.

DOE Office of Scientific and Technical Information (OSTI.GOV)

ALTIC, NICK A

In March 2011, the USNS Bridge was deployed off northeastern Honshu, Japan with the carrier USS Ronald Reagan to assist with relief efforts after the 2011 Tōhoku earthquake and tsunami. During that time, the Bridge was exposed to air-borne radioactive materials leaking from the damaged Fukushima I Nuclear Power Plant. The proximity of the Bridge to the air-borne impacted area resulted in the contamination of the ship’s air-handling systems and the associated components, as well as potential contamination of other ship surfaces due to either direct intake/deposition or inadvertent spread from crew/operational activities. Preliminary surveys in the weeks after themore » event confirmed low-level contamination within the heating, ventilation, and air conditioning (HVAC) ductwork and systems, and engine and other auxiliary air intake systems. Some partial decontamination was performed at that time. In response to the airborne contamination event, Military Sealift Fleet Support Command (MSFSC) contracted Oak Ridge Associated Universities (ORAU), under provisions of the Oak Ridge Institute for Science and Education (ORISE) contract, to assess the radiological condition of the Bridge. Phase I identified contamination within the CPS filters, ventilation systems, miscellaneous equipment, and other suspect locations that could not accessed at that time (ORAU 2011b). Because the Bridge was underway during the characterization, all the potentially impacted systems/spaces could not be investigated. As a result, MSFSC contracted with ORAU to perform Phase II of the characterization, specifically to survey systems/spaces previously inaccessible. During Phase II of the characterization, the ship was in port to perform routine maintenance operations, allowing access to the previously inaccessible systems/spaces.« less

Weaning from mechanical ventilation: why are we still looking for alternative methods?

PubMed

Frutos-Vivar, F; Esteban, A

2013-12-01

Most patients who require mechanical ventilation for longer than 24 hours, and who improve the condition leading to the indication of ventilatory support, can be weaned after passing a first spontaneous breathing test. The challenge is to improve the weaning of patients who fail that first test. We have methods that can be referred to as traditional, such as the T-tube, pressure support or synchronized intermittent mandatory ventilation (SIMV). In recent years, however, new applications of usual techniques as noninvasive ventilation, new ventilation methods such as automatic tube compensation (ATC), mandatory minute ventilation (MMV), adaptive support ventilation or automatic weaning systems based on pressure support have been described. Their possible role in weaning from mechanical ventilation among patients with difficult or prolonged weaning remains to be established. Copyright © 2012 Elsevier España, S.L. and SEMICYUC. All rights reserved.

Circuit compliance compensation in lung protective ventilation.

PubMed

Masselli, Grazia Maria Pia; Silvestri, Sergio; Sciuto, Salvatore Andrea; Cappa, Paolo

2006-01-01

Lung protective ventilation utilizes low tidal volumes to ventilate patients with severe lung pathologies. The compensation of breathing circuit effects, i.e. those induced by compressible volume of the circuit, results particularly critical in the calculation of the actual tidal volume delivered to patient's respiratory system which in turns is responsible of the level of permissive hypercapnia. The present work analyzes the applicability of the equation for circuit compressible volume compensation in the case of pressure and volume controlled lung protective ventilation. Experimental tests conducted in-vitro show that the actual tidal volume can be reliably estimated if the compliance of the breathing circuit is measured with the same parameters and ventilation technique that will be utilized in lung protective ventilation. Differences between volume and pressure controlled ventilation are also quantitatively assessed showing that pressure controlled ventilation allows a more reliable compensation of breathing circuit compressible volume.

No Sweat.

ERIC Educational Resources Information Center

Strickland, Gary

2001-01-01

Explains how changes in school design in the last 10 years have caused heating, ventilation, and cooling system (HVAC) designers to reexamine their choice of classroom unit ventilators (UV). The influence of indoor lighting systems, insulation, indoor air quality, energy code compliance, and HVAC system design on UV decision making are also…

Positive pressure ventilation in a patient with a right upper lobar bronchocutaneous fistula: right upper bronchus occlusion using the cuff of a left-sided double lumen endobronchial tube.

PubMed

Omori, Chieko; Toyama, Hiroaki; Takei, Yusuke; Ejima, Yutaka; Yamauchi, Masanori

2017-08-01

In patients with a bronchocutaneous fistula, positive pressure ventilation leads to air leakage and potential hypoxemia. A male patient with a right upper bronchocutaneous fistula was scheduled for esophageal reconstruction. His preoperative chest computed tomography image revealed aeration in the right middle and lower lobe, a large bulla in the left upper lobe, and pleural effusion and pneumonia in the left lower lobe. Therefore, left one-lung ventilation was considered to result in hypoxemia. Before anesthesia induction, the bronchocutaneous fistula was covered with gauze and film to prevent air leakage. After anesthesia induction, mask ventilation was performed with a peak positive pressure of 10 cmH 2 O. A left-sided double lumen endobronchial tube (DLT) was then inserted into the right main bronchus for occluding only the right superior bronchus, and two-lung ventilation was performed to minimize airway pressure and maintain oxygenation, which did not cause air leakage through the fistula. During anesthesia, no ventilation-related difficulty was faced. The method of inserting a left-sided DLT into the right main bronchus and occluding the right upper bronchus selectively by bronchial cuff is considered to be an option for mechanical ventilation in patients with a right upper bronchial fistula, as demonstrated in the present case.

Effect of mechanical ventilation on systemic oxygen extraction and lactic acidosis during early septic shock in rats.

PubMed

Griffel, M I; Astiz, M E; Rackow, E C; Weil, M H

1990-01-01

We studied the effect of mechanical ventilation on systemic oxygen extraction and lactic acidosis in peritonitis and shock in rats. Sepsis was induced by cecal ligation and perforation. After tracheostomy, rats were randomized to spontaneous breathing (S) or mechanical ventilation with paralysis (V). Five animals were studied in each group. The V animals were paralyzed with pancuronium bromide to eliminate respiratory effort. Mechanical ventilation consisted of controlled ventilation using a rodent respirator with periodic adjustment of minute ventilation to maintain PaCO2 and pH within normal range. Arterial and central venous blood gases and thermodilution cardiac output were measured at baseline before abdominal surgery, and sequentially at 0.5, 3.5, and 6 h after surgery. At 6 h, cardiac output was 193 +/- 30 ml/kg.min in S animals and 199 +/- 32 ml/kg.min in V animals (NS). The central venous oxygen saturation was 27.4 +/- 4.7% in S animals and 30.0 +/- 6.4% in V animals (NS). Systemic oxygen extraction was 70 +/- 5% in S animals and 67 +/- 6% in V animals (NS). Arterial lactate was 2.4 +/- 0.4 mmol/L in S animals and 2.2 +/- 0.5 mmol/L in V animals (NS). The S animals developed lethal hypotension at 6.6 +/- 0.4 h compared to 6.8 +/- 0.4 h in V animals (NS). These data suggest that mechanical ventilation does not decrease systemic oxygen extraction or ameliorate the development of lactic acidosis during septic shock.

Influence of ambient temperature and minute ventilation on passive and active heat and moisture exchangers.

PubMed

Lellouche, François; Qader, Siham; Taillé, Solenne; Lyazidi, Aissam; Brochard, Laurent

2014-05-01

During invasive mechanical ventilation, inspired gases must be humidified. We previously showed that high ambient temperature greatly impaired the hygrometric performance of heated wire-heated humidifiers. The aim of this bench and clinical study was to assess the humidification performance of passive and active heat and moisture exchangers (HMEs) and the impact of ambient temperature and ventilator settings. We first tested on the bench a device with passive and active humidification properties (Humid-Heat, Teleflex), and 2 passive hydrophobic/hygroscopic HMEs (Hygrobac and Hygrobac S, Tyco Healthcare). The devices were tested at 3 different ambient temperatures (from 22 to 30 °C), and at 2 minute ventilation settings (10 and 20 L/min). Inspired gas hygrometry was measured at the Y-piece with the psychrometric method. In addition to the bench study, we measured the hygrometry of inspired gases in 2 different clinical studies. In 15 mechanically ventilated patients, we evaluated Humid-Heat at different settings. Additionally, we evaluated Humid-Heat and compared it with Hygrobac in a crossover study in 10 patients. On the bench, with the Hygrobac and Hygrobac S the inspired absolute humidity was ∼ 30 mg H2O/L, and with the Humid-Heat, slightly < 35 mg H2O/L. Ambient temperature and minute ventilation did not have a clinically important difference on the performance of the tested devices. During the clinical evaluation, Humid-Heat provided inspired humidity in a range from 28.5 to 42.0 mg H2O/L, depending on settings, and was only weakly influenced by the patient's body temperature. In this study both passive and active HMEs had stable humidification performance with negligible influence of ambient temperature and minute ventilation. This contrasts with previous findings with heated wire-heated humidifiers. Although there are no clear data demonstrating that higher humidification impacts outcomes, it is worth noting that humidity was significantly higher with the active HME.

Joint Service Chemical and Biological Defense Program FY 08-09 Overview

DTIC Science & Technology

2007-10-01

of human plasma-derived butyrylcholinesterase Electronmicrograph of bacillus spores adhering to cell membrane processes Jo i n t Se rv i c e ch e m i...human performance within CB-protective systems. Carbon monolith for electro-swing adsorption Bacillus globigii spores collecting on an...integrated with the ship’s heating, ventilation, and air-conditioning ( HVAC ) systems and provides a filter air supply air for overpressurization of

Evaluation of Variable Refrigerant Flow Systems Performance on Oak Ridge National Laboratory s Flexible Research Platform: Part 1 Cooling Season Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Im, Piljae; Malhotra, Mini; Munk, Jeffrey D.

This report provides second-year cooling season test results for the multi-year project titled “Evaluation of Variable Refrigeration Flow (VRF) System on Oak Ridge National Laboratory (ORNL)’s Flexible Research Platform (FRP).” The purpose of the second-year project was to (1) evaluate the full- and partload performance of VRF systems compared with an existing baseline heating, ventilation, and airconditioning (HVAC) system, which is a conventional rooftop unit (RTU) variable-air-volume (VAV) system with electric resistance heating and (2) use hourly building energy simulation to evaluate the energy savings potential of using VRF systems in major US cities. The second-year project performance period wasmore » from July 2015 through June 2016.« less

Effect of switching off unidirectional downflow systems of operating theaters during prolonged inactivity on the period before the operating theater can safely be used.

PubMed

Traversari, A A L; Bottenheft, C; van Heumen, S P M; Goedhart, C A; Vos, M C

2017-02-01

Switching off air handling systems in operating theaters during periods of prolonged inactivity (eg, nights, weekends) can produce a substantial reduction of energy expenditure. However, little evidence is available regarding the effect of switching off the air handling system during periods of prolonged inactivity on the air quality in operating theaters during operational periods. The aim of this study is to determine the amount of time needed after restarting the ventilation system to return to a stable situation, with air quality at least equal to the situation before switching off the system. Measurements were performed in 3 operating theaters, all of them equipped with a unidirectional downflow (UDF) system. Measurements (particle counts of emitted particles with a particle size ≥0.5 µm) were taken during the start-up of the ventilation system to determine when prespecified degrees of protection were achieved. Temperature readings were taken to determine when a stable temperature difference between the periphery and the protected area was reached, signifying achievement of a stable condition. After starting up the system, the protected area achieved the required degrees of protection within 20 minutes (95% upper confidence limit). A stable temperature difference was achieved within 23 minutes (95% upper confidence limit). Both findings lie well within the period of 25 minutes normally required for preparations before the start of surgical procedures. Switching off the ventilation system during prolonged inactivity (during the night and weekend) has no negative effect on the air quality in UDF operating theaters during normal operational hours. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Low-Flow Extracorporeal Carbon Dioxide Removal Using the Hemolung Respiratory Dialysis System® to Facilitate Lung-Protective Mechanical Ventilation in Acute Respiratory Distress Syndrome.

PubMed

Akkanti, Bindu; Rajagopal, Keshava; Patel, Kirti P; Aravind, Sangeeta; Nunez-Centanu, Emmanuel; Hussain, Rahat; Shabari, Farshad Raissi; Hofstetter, Wayne L; Vaporciyan, Ara A; Banjac, Igor S; Kar, Biswajit; Gregoric, Igor D; Loyalka, Pranav

2017-06-01

Extracorporeal carbon dioxide removal (ECCO 2 R) permits reductions in alveolar ventilation requirements that the lungs would otherwise have to provide. This concept was applied to a case of hypercapnia refractory to high-level invasive mechanical ventilator support. We present a case of an 18-year-old man who developed post-pneumonectomy acute respiratory distress syndrome (ARDS) after resection of a mediastinal germ cell tumor involving the left lung hilum. Hypercapnia and hypoxemia persisted despite ventilator support even at traumatic levels. ECCO 2 R using a miniaturized system was instituted and provided effective carbon dioxide elimination. This facilitated establishment of lung-protective ventilator settings and lung function recovery. Extracorporeal lung support increasingly is being applied to treat ARDS. However, conventional extracorporeal membrane oxygenation (ECMO) generally involves using large cannulae capable of carrying high flow rates. A subset of patients with ARDS has mixed hypercapnia and hypoxemia despite high-level ventilator support. In the absence of profound hypoxemia, ECCO 2 R may be used to reduce ventilator support requirements to lung-protective levels, while avoiding risks associated with conventional ECMO.

[Monitorization of respiratory mechanics in the ventilated patient].

PubMed

García-Prieto, E; Amado-Rodríguez, L; Albaiceta, G M

2014-01-01

Monitoring during mechanical ventilation allows the measurement of different parameters of respiratory mechanics. Accurate interpretation of these data can be useful for characterizing the situation of the different components of the respiratory system, and for guiding ventilator settings. In this review, we describe the basic concepts of respiratory mechanics, their interpretation, and their potential use in fine-tuning mechanical ventilation. Copyright © 2013 Elsevier España, S.L. y SEMICYUC. All rights reserved.

Analysis on ventilation pressure of fire area in longitudinal ventilation of underground tunnel

NASA Astrophysics Data System (ADS)

Li, Jiaxin; Li, Yanfeng; Feng, Xiao; Li, Junmei

2018-03-01

In order to solve the problem of ventilation pressure loss in the fire area under the fire condition, the wind pressure loss model of the fire area is established based on the thermodynamic equilibrium relation. The semi-empirical calculation formula is obtained by using the model experiment and CFD simulation. The validity of the formula is verified. The results show that the ventilation pressure loss in the fire zone is proportional to the convective heat release rate at the critical velocity, which is inversely proportional to the upstream ventilation velocity and the tunnel cross-sectional area. The proposed formula is consistent with the law of the tunnel fire test fitting formula that results are close, in contrast, the advantage lies in a clear theoretical basis and ventilation velocity values. The resistance of road tunnel ventilation system is calculated accurately and reliably, and then an effective emergency ventilation operation program is developed. It is necessary to consider the fire zone ventilation pressure loss. The proposed ventilation pressure loss formula can be used for design calculation after thorough verification.

Outbreak of Bacillus cereus infections in a neonatal intensive care unit traced to balloons used in manual ventilation.

PubMed

Van Der Zwet, W C; Parlevliet, G A; Savelkoul, P H; Stoof, J; Kaiser, A M; Van Furth, A M; Vandenbroucke-Grauls, C M

2000-11-01

In 1998, an outbreak of systemic infections caused by Bacillus cereus occurred in the Neonatal Intensive Care Unit of the University Hospital Vrije Universiteit, Amsterdam, The Netherlands. Three neonates developed sepsis with positive blood cultures. One neonate died, and the other two neonates recovered. An environmental survey, a prospective surveillance study of neonates, and a case control study were performed, in combination with molecular typing, in order to identify potential sources and transmission routes of infection. Genotypic fingerprinting by amplified-fragment length polymorphism (AFLP) showed that the three infections were caused by a single clonal type of B. cereus. The same strain was found in trachea aspirate specimens of 35 other neonates. The case control study showed mechanical ventilation with a Sensormedics ventilation machine to be a risk factor for colonization and/or infection (odds ratio, 9.8; 95% confidence interval, 1.1 to 88.2). Prospective surveillance showed that colonization with B. cereus occurred exclusively in the respiratory tract of mechanically ventilated neonates. The epidemic strain of B. cereus was found on the hands of nursing staff and in balloons used for manual ventilation. Sterilization of these balloons ended the outbreak. We conclude that B. cereus can cause outbreaks of severe opportunistic infection in neonates. Typing by AFLP proved very useful in the identification of the outbreak and in the analysis of strains recovered from the environment to trace the cause of the epidemic.

Outbreak of Bacillus cereus Infections in a Neonatal Intensive Care Unit Traced to Balloons Used in Manual Ventilation

PubMed Central

Van Der Zwet, Wil C.; Parlevliet, Gerard A.; Savelkoul, Paul H.; Stoof, Jeroen; Kaiser, Annie M.; Van Furth, A. Marceline; Vandenbroucke-Grauls, Christina M.

2000-01-01

In 1998, an outbreak of systemic infections caused by Bacillus cereus occurred in the Neonatal Intensive Care Unit of the University Hospital Vrije Universiteit, Amsterdam, The Netherlands. Three neonates developed sepsis with positive blood cultures. One neonate died, and the other two neonates recovered. An environmental survey, a prospective surveillance study of neonates, and a case control study were performed, in combination with molecular typing, in order to identify potential sources and transmission routes of infection. Genotypic fingerprinting by amplified-fragment length polymorphism (AFLP) showed that the three infections were caused by a single clonal type of B. cereus. The same strain was found in trachea aspirate specimens of 35 other neonates. The case control study showed mechanical ventilation with a Sensormedics ventilation machine to be a risk factor for colonization and/or infection (odds ratio, 9.8; 95% confidence interval, 1.1 to 88.2). Prospective surveillance showed that colonization with B. cereus occurred exclusively in the respiratory tract of mechanically ventilated neonates. The epidemic strain of B. cereus was found on the hands of nursing staff and in balloons used for manual ventilation. Sterilization of these balloons ended the outbreak. We conclude that B. cereus can cause outbreaks of severe opportunistic infection in neonates. Typing by AFLP proved very useful in the identification of the outbreak and in the analysis of strains recovered from the environment to trace the cause of the epidemic. PMID:11060080