title: Inward Leakage Variability between Respirator Fit Test Panels - Part I. Deterministic Approach.
abstract: Inter-panel variability has never been investigated. The objective of this study was to determine the variability between different anthropometric panels used to determine the inward leakage (IL) of N95 filtering facepiece respirators (FFRs) and elastomeric half-mask respirators (EHRs). A total of 144 subjects, who were both experienced and non-experienced N95 FFR users, were recruited. Five N95 FFRs and five N95 EHRs were randomly selected from among those models tested previously in our laboratory. The PortaCount Pro+ (without N95-Companion) was used to measure IL of the ambient particles with a detectable size range of 0.02 to 1 μm. The Occupational Safety and Health Administration standard fit test exercises were used for this study. IL test were performed for each subject using each of the 10 respirators. Each respirator/subject combination was tested in duplicate, resulting in a total 20 IL tests for each subject. Three 35-member panels were randomly selected without replacement from the 144 study subjects stratified by the National Institute for Occupational Safety and Health bivariate panel cell for conducting statistical analyses. The geometric mean (GM) IL values for all 10 studied respirators were not significantly different among the three randomly selected 35-member panels. Passing rate was not significantly different among the three panels for all respirators combined or by each model. This was true for all IL pass/fail levels of 1%, 2%, and 5%. Using 26 or more subjects to pass the IL test, all three panels had consistent passing/failing results for pass/fail levels of 1% and 5%. Some disagreement was observed for the 2% pass/fail level. Inter-panel variability exists, but it is small relative to the other sources of variation in fit testing data. The concern about inter-panel variability and other types of variability can be alleviated by properly selecting: pass/fail level (IL 1-5%); panel size (e.g., 25 or 35); and minimum number of subjects required to pass (e.g., 26 of 35 or 23 of 35).
authors.affiliation: a National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory , Pittsburgh , Pennsylvania.
authors.forename: Ziqing
authors.initials: Z
authors.lastname: Zhuang
authors.affiliation: a National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory , Pittsburgh , Pennsylvania.|b Institute of Health Surveillance, Analysis and Protection, Hubei Center for Disease Control and Prevention , Wuhan , Hubei , China.
authors.forename: Yuewei
authors.initials: Y
authors.lastname: Liu
authors.affiliation: a National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory , Pittsburgh , Pennsylvania.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Coffey
authors.affiliation: a National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory , Pittsburgh , Pennsylvania.
authors.forename: Colleen
authors.initials: C
authors.lastname: Miller
authors.affiliation: a National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory , Pittsburgh , Pennsylvania.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Szalajda
mesh_terms: D000328:Adult; D005374:Filtration / Q000295:instrumentation*; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis / Q000517:prevention & control*; D008397:Masks / Q000592:standards*; D008422:Materials Testing / Q000379:methods*; D009314:National Institute for Occupational Safety and Health, U.S.; D016273:Occupational Exposure / Q000517:prevention & control; D052638:Particulate Matter; D015203:Reproducibility of Results; D012134:Respiratory Protective Devices / Q000592:standards*; D014481:United States; D014489:United States Occupational Safety and Health Administration
chemical_list: D052638:Particulate Matter
keywords: fit test; inter- and intra-subject variability; inter-panel variability; respirator fit test panel; respirators