ILO Home
Go to the home page
Site map | Contact us Franšais | Espa˝ol

CISDOC database

Document ID (ISN)112182
CIS number 11-0843
ISSN - Serial title 1545-9624 - Journal of Occupational and Environmental Hygiene
Year 2009
Convention or series no.
Author(s) Grinshpun S.A., Haruta H., Eninger R.M., Reponen T., McKay R.T., Lee S.A.
Title Performance of an N95 filtering facepiece particulate respirator and a surgical mask during human breathing: Two pathways for particle penetration
Bibliographic information Oct. 2009, Vol.6, No.10, p.593-603. Illus. 20 ref.
Internet access Performance_of_an_N95.pdf [in English]
Abstract The protection level offered by filtering facepiece particulate respirators and face masks is defined by the percentage of ambient particles penetrating inside the protection device. There are two penetration pathways, through the faceseal leakage and through the filter medium. This study aimed at differentiating the contributions of these two pathways for particles in the size range of 0.03-1 μm under actual breathing conditions. One N95 filtering facepiece respirator and one surgical mask commonly used in health care environments were tested on 25 subjects (matching the latest National Institute for Occupational Safety and Health fit testing panel) as the subjects performed conventional fit test exercises. The respirator and the mask were also tested with breathing manikins that precisely mimicked the pre-recorded breathing patterns of the tested subjects. The penetration data obtained in the human subject- and manikin-based tests were compared for different particle sizes and breathing patterns. Overall, 5250 particle size- and exercise-specific penetration values were determined. For each value, the faceseal leakage-to-filter ratio was calculated to quantify the relative contributions of the two penetration pathways. The number of particles penetrating through the faceseal leakage of the tested respirator/mask far exceeded the number of those penetrating through the filter medium. Because most of the penetrated particles entered through the faceseal, the priority in respirator/mask development should be shifted from improving the efficiency of the filter medium to establishing a better fit that would eliminate or minimize faceseal leakage.
Descriptors (primary) filtration efficiency; leakage testing; particulate removing respirators
Descriptors (secondary) particle size; equipment testing; comparative study; reliability; public OSH institutions
Document type D - Periodical articles
Subject(s) Personal protection
Broad subject area(s) Chemical safety
Browse category(ies) Personal protection