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Evaluation of the filtration performance of 21 N95 filtering face piece respirators after prolonged storage
Evaluation of the filtration performance of 21 N95 filtering face piece respirators after prolonged storage
Dennis J. Viscusi, BSa, Mike Bergman, MSb, Edward Sinkule, MSa, Ronald E. Shaffer, PhDa
published online 02 February 2009.
Background
Organizations are stockpiling respirators to prepare for an influenza pandemic. To understand better the effects of prolonged storage, this investigation evaluated the filtration efficiency of 21 different models of National Institute for Occupational Safety and Health (NIOSH)-certified disposable N95 filtering face piece respirators. These respirators had been stored in their original packaging for a period of at least 6 years in research laboratories and dry warehouse facilities, ranging in temperature between 15?C and 32?C and relative humidity between 20% and 80%.
Methods
Filter penetration was measured using an abbreviated version of the NIOSH respirator certification test incorporating a polydisperse sodium chloride aerosol at 85 L/min.
Results
Of the 21 respirator models tested, 19 models had both average penetration results of less than 5%. Mean initial penetration values ranged from 0.39% to 5.83%, whereas mean maximum penetration values ranged from 0.95% to 5.83%. There did not appear to be any correlation between the length of storage and failure to pass the filtration test.
Conclusion
Results indicate that most N95 filtering face piece respirators stored for up to 10 years at warehouse conditions will likely have expected levels of filtration performance and that the degree of filtration efficiency degradation is likely model specific.
Pittsburgh, Pennsylvania
a National Institute for Occupational Safety and Health
b National Personal Protective Technology Laboratory; and EG&G Technical Services, Inc, Pittsburgh, PA
Address correspondence to Ronald E. Shaffer, PhD, Chief, Technology Research Branch, National Personal Protective Technology Lab (NPPTL), National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC), 626 Cochrans Mill Road, Building 29, P.O. Box 18070, Pittsburgh, PA 15236.
The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health (NIOSH). Mention of company names or products does not constitute endorsement by NIOSH. Conflicts of interest: The authors report no conflicts of interest.
PII: S0196-6553(08)00853-5
doi:10.1016/j.ajic.2008.09.021
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<cite cite="http://www.ajicjournal.org/article/S0196-6553(08)00853-5/abstract">Evaluation of the filtration performance of 21 N95 filtering face piece respirators after prolonged storage</cite>
Dennis J. Viscusi, BSa, Mike Bergman, MSb, Edward Sinkule, MSa, Ronald E. Shaffer, PhDa
published online 02 February 2009.
Background
Organizations are stockpiling respirators to prepare for an influenza pandemic. To understand better the effects of prolonged storage, this investigation evaluated the filtration efficiency of 21 different models of National Institute for Occupational Safety and Health (NIOSH)-certified disposable N95 filtering face piece respirators. These respirators had been stored in their original packaging for a period of at least 6 years in research laboratories and dry warehouse facilities, ranging in temperature between 15?C and 32?C and relative humidity between 20% and 80%.
Methods
Filter penetration was measured using an abbreviated version of the NIOSH respirator certification test incorporating a polydisperse sodium chloride aerosol at 85 L/min.
Results
Of the 21 respirator models tested, 19 models had both average penetration results of less than 5%. Mean initial penetration values ranged from 0.39% to 5.83%, whereas mean maximum penetration values ranged from 0.95% to 5.83%. There did not appear to be any correlation between the length of storage and failure to pass the filtration test.
Conclusion
Results indicate that most N95 filtering face piece respirators stored for up to 10 years at warehouse conditions will likely have expected levels of filtration performance and that the degree of filtration efficiency degradation is likely model specific.
Pittsburgh, Pennsylvania
a National Institute for Occupational Safety and Health
b National Personal Protective Technology Laboratory; and EG&G Technical Services, Inc, Pittsburgh, PA
Address correspondence to Ronald E. Shaffer, PhD, Chief, Technology Research Branch, National Personal Protective Technology Lab (NPPTL), National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC), 626 Cochrans Mill Road, Building 29, P.O. Box 18070, Pittsburgh, PA 15236.
The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health (NIOSH). Mention of company names or products does not constitute endorsement by NIOSH. Conflicts of interest: The authors report no conflicts of interest.
PII: S0196-6553(08)00853-5
doi:10.1016/j.ajic.2008.09.021
-