The Experts below are selected from a list of 201 Experts worldwide ranked by ideXlab platform
Alex G. Pappas - One of the best experts on this subject based on the ideXlab platform.
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Domestic Preparedness Program: Protection Factor Testing of the Se-Shield Suit with the SE400 Powered Air Purifying Respirator (PAPR)
2004Co-Authors: Adam D. Seiple, Alex G. PappasAbstract:Abstract : Intact suit was challenged with corn oil to simulate a biological or chemical aerosol. Protection factors were determined for the suit.
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Protection Factor Testing of the 3M Breathe Easy (BE-10) Powered Air Purifying Respirator (PAPR)
2003Co-Authors: Adam D. Seiple, Alex G. PappasAbstract:Abstract : This report describes the results of the performance testing of the 3M Breathe Easy (BE-10) Powered Air Purifying Respirator. A series of tests were performed to determine the corn-oil protection factors using human subjects.
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Domestic Preparedness: Phase 2 Sarin Vapor Challenge and Corn Oil Protection Factor (PF) Testing of Commercial Powered Air Purifying Respirator (PAPR) Systems and Cartridges
2002Co-Authors: Lee E. Campbell, Ray Lins, Alex G. PappasAbstract:Abstract : Results of performance testing of commercial powered air purifying Respirator (PAPR) systems and cartridges are described. Three series of tests were performed: (1) breakthrough time determinations of cartridges against Sarin (GB); (2) GB vapor penetration determination of entire PAPR systems using manikin headform and simulated breathing; and (3) corn-oil protection factor determinations of PAPR systems using human subjects. Results indicate that cartridges provide complete penetration resistance against 200 mg/m(3) GB challenge concentrations for 60 min, but unacceptably high levels of GB vapor and corn oil aerosol may penetrate into the breathing zone of the PAPRs.
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Domestic Preparedness: Sarin Vapor Challenge and Corn Oil Protection Factor (PF) Testing of 3M BE10 Powered Air Purifying Respirator (PAPR) With AP3 Cartridge
2001Co-Authors: Lee E. Campbell, Ray Lins, Alex G. PappasAbstract:Abstract : Results of performance testing of the 3M Model BE10 powered Air-Purifying Respirator (PAPR) are described. Three series of tests were performed: (1) breakthrough time determinations of PAPR Cartridge Model AP3 against sarin (GB); (2) GB vapor penetration determination of entire PAPR systems using manikin headform and simulated breathing, and (3) corn-oil protection factor determinations of PAPR systems using human subjects. Results indicate that cartridges provide adequate resistance to GB penetration against high-concentration challenges, but that corn oil aerosol and high-concentration GB vapor penetration into the breathing zone of the PAPR occurs at high levels, possibly through the hood-type head enclosure and/or the exhalation valve.
Kaarle J. Hämeri - One of the best experts on this subject based on the ideXlab platform.
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Workplace performance of a loose-fitting powered air purifying Respirator during nanoparticle synthesis
Journal of Nanoparticle Research, 2020Co-Authors: Antti J. Koivisto, Mikko Aromaa, Ismo K. Koponen, Wouter Fransman, Keld A. Jensen, Jyrki M. Mäkelä, Kaarle J. HämeriAbstract:Nanoparticle (particles with diameter ≤100 nm) exposure is recognized as a potentially harmful size fraction for pulmonary particle exposure. During nanoparticle synthesis, the number concentrations in the process room may exceed 10 × 106 cm−3. During such conditions, it is essential that the occupants in the room wear highly reliable high-performance Respirators to prevent inhalation exposure. Here we have studied the in-use program protection factor (PPF) of loose-fitting powered air purifying Respirators, while workers were coating components with TiO 2 or Cu x O y nanoparticles under a hood using a liquid flame spray process. The PPF was measured using condensation particle counters, an electrical low pressure impactor, and diffusion chargers. The room particle concentrations varied from 4 × 106 to 40 × 106 cm−3, and the count median aerodynamic diameter ranged from 32 to 180 nm. Concentrations inside the Respirator varied from 0.7 to 7.2 cm−3. However, on average, tidal breathing was assumed to increase the Respirator concentration by 2.3 cm−3. The derived PPF exceeded 1.1 × 106, which is more than 40 × 103 times the Respirator assigned protection factor. We were unable to measure clear differences in the PPF of Respirators with old and new filters, among two male and one female user, or assess most penetrating particle size. This study shows that the loose-fitting powered air purifying Respirator provides very efficient protection against nanoparticle inhalation exposure if used properly. © 2015, Springer Science+Business Media Dordrecht.
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Workplace performance of a loose-fitting powered air purifying Respirator during nanoparticle synthesis
Journal of Nanoparticle Research, 2015Co-Authors: Antti J. Koivisto, Mikko Aromaa, Ismo K. Koponen, Wouter Fransman, Keld A. Jensen, Jyrki M. Mäkelä, Kaarle J. HämeriAbstract:Nanoparticle (particles with diameter ≤100 nm) exposure is recognized as a potentially harmful size fraction for pulmonary particle exposure. During nanoparticle synthesis, the number concentrations in the process room may exceed 10 × 10^6 cm^−3. During such conditions, it is essential that the occupants in the room wear highly reliable high-performance Respirators to prevent inhalation exposure. Here we have studied the in-use program protection factor (PPF) of loose-fitting powered air purifying Respirators, while workers were coating components with TiO_2 or Cu_ x O_ y nanoparticles under a hood using a liquid flame spray process. The PPF was measured using condensation particle counters, an electrical low pressure impactor, and diffusion chargers. The room particle concentrations varied from 4 × 10^6 to 40 × 10^6 cm^−3, and the count median aerodynamic diameter ranged from 32 to 180 nm. Concentrations inside the Respirator varied from 0.7 to 7.2 cm^−3. However, on average, tidal breathing was assumed to increase the Respirator concentration by 2.3 cm^−3. The derived PPF exceeded 1.1 × 10^6, which is more than 40 × 10^3 times the Respirator assigned protection factor. We were unable to measure clear differences in the PPF of Respirators with old and new filters, among two male and one female user, or assess most penetrating particle size. This study shows that the loose-fitting powered air purifying Respirator provides very efficient protection against nanoparticle inhalation exposure if used properly.
Gerry O. Wood - One of the best experts on this subject based on the ideXlab platform.
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Estimating Reusability of Organic Air-Purifying Respirator Cartridges
Journal of Occupational and Environmental Hygiene, 2011Co-Authors: Gerry O. Wood, Jay L. SnyderAbstract:Reuse of organic vapor Air-Purifying Respirator cartridges after a job or shift can provide economy and energy savings. However, standards and manufacturers' guidance discourage reuse, presumably due to a lack of quantitative objective exposure and use information. Storage and simulated reuse laboratory studies and modeling have been done to provide such information. Two important parameters of breakthrough curves, midpoint time (related to adsorption capacity) and midpoint slope (related to adsorption rate), have been shown to be unchanged during storage for reuse. Extrapolations to smaller breakthrough concentrations and times can be made from this reference breakthrough and time. Significant step increases in breakthrough concentration upon cartridge reuse have been observed in some cases. Values of immediate breakthrough concentrations upon reuse (IBURs) have been measured and correlated. The Dubinin/Radushkevich adsorption isotherm equation has been used to estimate maximum IBURs, which depend on man...
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Estimating service lives of Air-Purifying Respirator cartridges for reactive gas removal.
Journal of Occupational and Environmental Hygiene, 2005Co-Authors: Gerry O. WoodAbstract:A mathematical model has been developed to estimate service lives of Air-Purifying Respirator cartridges that remove gases reactively from flowing air. Most gases, because of their high volatility and low polarizability, are not effectively removed by physical adsorption on activated carbon. Models previously developed for toxic organic vapors cannot estimate service lives of cartridges for toxic gases. Often, an activated carbon is impregnated with a chemical to enhance gas removal by chemical reaction(s). The kinds of reactions, types and amounts of impregnants, and effects of the presence of water vary; therefore, the model requires user inputs of gas capacity and water effect parameters. Ideally, these should be available from manufacturers of the cartridges. If they are not, they can be extracted from measured breakthrough times using this model. The key to this model is the observation that adsorption rates of gases can be adequately quantified by the same correlations that have been reported for or...
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Estimating Service Lives of Organic Vapor Cartridges II: A Single Vapor at All Humidities
Journal of Occupational and Environmental Hygiene, 2004Co-Authors: Gerry O. WoodAbstract:A widely used equation model for estimating service lives of organic vapor Air-Purifying Respirator cartridges has been updated with more recent research results. It has been expanded to account for effects of high relative humidities. Adsorption capacity competition between water vapor and organic vapor is largely explained by mutual exclusion of adsorption volume of the activated carbon. The Dubinin/Radushkevich equation is used to describe the adsorption isotherms of both water and organic vapors. Effects of relative humidity and adsorbed water on adsorption rates are described by an empirical correlation with breakthrough times. The dynamic natures of adsorption and competition are incorporated using an expanding zone model with displaced water rollup. The complete model has been tested and verified with published and unpublished data from many sources.
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Carbon Tetrachloride Replacement Compounds for Organic Vapor Air-Purifying Respirator Cartridge and Activated Carbon Testing—A Review
American Industrial Hygiene Association Journal, 2001Co-Authors: Ernest S. Moyer, Simon J. Smith, Gerry O. WoodAbstract:This article reviews efforts by researchers and organizations around the world to identify chemicals as substitutes for carbon tetrachloride in measuring activated carbon activity (adsorption capacity) or organic vapor Air-Purifying Respirator cartridge (or other packed carbon bed) breakthrough times. Such measurements usually are done to determine if a minimum performance standard is met. Different criteria have been established, supporting data developed and used, and conclusions reached. This article presents relevant published, unpublished, obscure, and recalculated data which the reader can use to make a choice of replacement chemical and testing conditions. No recommendations for a specific replacement chemical are endorsed or promoted in this review.
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Reusability study with organic vapor Air-Purifying Respirator cartridges
1997Co-Authors: Gerry O. Wood, R. KissaneAbstract:The question often arises about the reusability of organic vapor adsorption beds, such as air- purifying Respirator cartridges, after periods of storage without use (airflow). The extremes of practice are: (1) use once and discard or (2) reuse multiple times assuming the protection is still afforded. The goal is to develop data and a model to provide guidance to decide when reuse is acceptable. They have studied the loss of protection of a commercial organic vapor cartridge after storage for varying periods of time. Three vapors (ethyl acetate, methylene chloride, and hexane) were individually loaded onto test cartridges using a breathing pump. Extents of loading, times of loading, and vapor concentrations were varied. After selected periods of storage the cartridges were again challenged with the same vapor concentration. The increases in concentration of a vapor in the effluent air (simulated breaths) from a cartridge immediately upon reuse depended on the storage period, the extent of loading during initial use, the volatility of the vapor, and the water vapor adsorbed, but not much on the vapor concentration.
Antti J. Koivisto - One of the best experts on this subject based on the ideXlab platform.
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Workplace performance of a loose-fitting powered air purifying Respirator during nanoparticle synthesis
Journal of Nanoparticle Research, 2020Co-Authors: Antti J. Koivisto, Mikko Aromaa, Ismo K. Koponen, Wouter Fransman, Keld A. Jensen, Jyrki M. Mäkelä, Kaarle J. HämeriAbstract:Nanoparticle (particles with diameter ≤100 nm) exposure is recognized as a potentially harmful size fraction for pulmonary particle exposure. During nanoparticle synthesis, the number concentrations in the process room may exceed 10 × 106 cm−3. During such conditions, it is essential that the occupants in the room wear highly reliable high-performance Respirators to prevent inhalation exposure. Here we have studied the in-use program protection factor (PPF) of loose-fitting powered air purifying Respirators, while workers were coating components with TiO 2 or Cu x O y nanoparticles under a hood using a liquid flame spray process. The PPF was measured using condensation particle counters, an electrical low pressure impactor, and diffusion chargers. The room particle concentrations varied from 4 × 106 to 40 × 106 cm−3, and the count median aerodynamic diameter ranged from 32 to 180 nm. Concentrations inside the Respirator varied from 0.7 to 7.2 cm−3. However, on average, tidal breathing was assumed to increase the Respirator concentration by 2.3 cm−3. The derived PPF exceeded 1.1 × 106, which is more than 40 × 103 times the Respirator assigned protection factor. We were unable to measure clear differences in the PPF of Respirators with old and new filters, among two male and one female user, or assess most penetrating particle size. This study shows that the loose-fitting powered air purifying Respirator provides very efficient protection against nanoparticle inhalation exposure if used properly. © 2015, Springer Science+Business Media Dordrecht.
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Workplace performance of a loose-fitting powered air purifying Respirator during nanoparticle synthesis
Journal of Nanoparticle Research, 2015Co-Authors: Antti J. Koivisto, Mikko Aromaa, Ismo K. Koponen, Wouter Fransman, Keld A. Jensen, Jyrki M. Mäkelä, Kaarle J. HämeriAbstract:Nanoparticle (particles with diameter ≤100 nm) exposure is recognized as a potentially harmful size fraction for pulmonary particle exposure. During nanoparticle synthesis, the number concentrations in the process room may exceed 10 × 10^6 cm^−3. During such conditions, it is essential that the occupants in the room wear highly reliable high-performance Respirators to prevent inhalation exposure. Here we have studied the in-use program protection factor (PPF) of loose-fitting powered air purifying Respirators, while workers were coating components with TiO_2 or Cu_ x O_ y nanoparticles under a hood using a liquid flame spray process. The PPF was measured using condensation particle counters, an electrical low pressure impactor, and diffusion chargers. The room particle concentrations varied from 4 × 10^6 to 40 × 10^6 cm^−3, and the count median aerodynamic diameter ranged from 32 to 180 nm. Concentrations inside the Respirator varied from 0.7 to 7.2 cm^−3. However, on average, tidal breathing was assumed to increase the Respirator concentration by 2.3 cm^−3. The derived PPF exceeded 1.1 × 10^6, which is more than 40 × 10^3 times the Respirator assigned protection factor. We were unable to measure clear differences in the PPF of Respirators with old and new filters, among two male and one female user, or assess most penetrating particle size. This study shows that the loose-fitting powered air purifying Respirator provides very efficient protection against nanoparticle inhalation exposure if used properly.
Raymond J. Roberge - One of the best experts on this subject based on the ideXlab platform.
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Powered Air-Purifying Respirator use in healthcare: Effects on thermal sensations and comfort
Journal of Occupational and Environmental Hygiene, 2020Co-Authors: Jeffrey B. Powell, Raymond J. RobergeAbstract:ABSTRACTTwelve subjects wore an N95 filtering facepiece Respirator (N95 FFR), one tight-fitting full facepiece powered Air-Purifying Respirator (PAPR), two loose-fitting PAPRs, and one elastomeric/PAPR hybrid for 1 hr each during treadmill walking at 5.6 km/hr while undergoing physiological and subjective response monitoring. No significant interaction (p ≥ .05) was noted between the five Respirators in heart rate, Respiratory rate, oxygen saturation, transcutaneous carbon dioxide, and perceptions of breathing effort or discomfort, exertion, facial heat, and overall body heat. Respirator deadspace heat/humidity were significantly greater for the N95 FFR, whereas tympanic forehead skin temperatures were significantly greater for the hybrid PAPR. Temperature of the facial skin covered by the Respirator was equivalent for the N95 FFR and hybrid PAPR, and both were significantly higher than for the other three PAPRs. Perception of eye dryness was significantly greater for a tight-fitting full facepiece PAPR t...
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Reusable elastomeric Air-Purifying Respirators: Physiologic impact on health care workers
American Journal of Infection Control, 2010Co-Authors: Raymond J. Roberge, Jeffrey B. Powell, Aitor Coca, W. Jon Williams, Andrew J. PalmieroAbstract:Background Elastomeric Air-Purifying Respirators offer the benefit of reusability, but their physiological impact on health care workers is unknown. Methods Ten health care workers exercised at 2 health care-associated work rates wearing an elastomeric Air-Purifying Respirator. Mixed inhalation/exhalation Respirator dead space gases (oxygen, carbon dioxide) were sampled, and physiological parameters were monitored (heart rate, breathing rate, tidal volume, minute volume, oxygen saturation, transcutaneous carbon dioxide). Numerical rating scales were used to evaluate comfort and exertion. Results Compared with controls (no Respirator), significant decreases in the breathing rate at both work rates ( P P Conclusion Reusable elastomeric Air-Purifying Respirators impose little additional physiological burden over the course of 1 hour at usual health care work rates. However, the potential for carbon dioxide retention in a significant proportion of users exists and requires further investigation.
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Wearing an N95 Respirator Concurrently With a Powered Air-Purifying Respirator: Effect on Protection Factor
Respiratory Care, 2008Co-Authors: Marc R. Roberge, Raymond J. Roberge, Mark R Vojtko, Richard J Vojtko, Douglas P. LandsittelAbstract:OBJECTIVE: To determine if using an N95 filtering face-piece Respirator concurrently with a loose-fitting powered Air-Purifying Respirator (PAPR) offers additional protection to the wearer. METHODS: We used a breathing mannequin programmed to deliver minute volumes of 25 L/min and 40 L/min. We measured the baseline protection factor of the PAPR with its motor operational and then deactivated (to simulate mechanical or battery failure). We tested 3 replicates of 3 different N95 models. We glued each N95 to the breathing mannequin and obtained a minimum protection factor of 100 at 25 L/min. We then placed the PAPR on the mannequin and took protection factor measurements with the N95-plus-PAPR combination, at 25 L/min and 40 L/min, with the PAPR operational and then deactivated. RESULTS: The N95 significantly increased the PAPR9s protection factor, even with the PAPR deactivated. The effect was multiplicative, not merely additive. CONCLUSIONS: An N95 decreases the concentration of airborne particles inspired by the wearer of a PAPR.
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Evaluation of the rationale for concurrent use of N95 filtering facepiece Respirators with loose-fitting powered Air-Purifying Respirators during aerosol-generating medical procedures
American Journal of Infection Control, 2008Co-Authors: Raymond J. RobergeAbstract:The concurrent use of N95 filtering facepiece Respirators with powered Air-Purifying Respirators during aerosol-generating medical procedures in patients with severe Respiratory pathogens has been promoted as offering additional protection against infectious agents. The purpose of this article is to examine the impact of this additional Respiratory equipment upon protection and personal performance. The presumed additive protective effect of an N95 filtering facepiece Respirator used concurrently with a powered Air-Purifying Respirator has not been subjected to rigorous scientific investigation. The burden imposed by additional Respiratory protective equipment should not be discounted, and the potentially minor contribution to protection may be offset by the negative impact on personal performance. Novel uses of protective equipment occasionally are spawned during crisis situations, but their generalized applicability to healthcare workers should ultimately be evidence-based.
