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The efficacy of four fit-test methods with N95 filtering-facepiece respirators.

CoffeyC; Zhuang-Z; Lawrence-R; Campbell-D
American Industrial Hygiene Conference and Exposition, May 20-25, 2000, Orlando, Florida. Fairfax, VA: American Industrial Hygiene Association, 2000 May; :45
The OSHA regulations on respirators (29 CFR 1910.134) allow respirator wearers to use four fittest methods to screen out poorly fitting N95 filtering- facepiece respirators: 1) the Bitrex(TM) (Denatonium benzoate) solution aerosol qualitative fit test; 2) the Portacount Test Instrument with the N95-Companion(TM) accessory (Companion); 3) the Portacount Test Instrument without the N95- Companion(TM) accessory (PortaCount); and 4) the generated aerosol quantitative fit-test. In this study, the results of these four tests were compared with total penetration factors, an indicator of whether a respirator provided an adequate facepiece fit to its wearer using the PortaCount Plus(TM). Total penetration, as defined in this study, comprises face-seal leakage and filter penetration. A respirator was determined to provide adequate protection if the 95th percentile of the total penetration calculated from six tests was less than or equal to 10 percent, which is equivalent to a protection factor greater than 10 - the level of protection often expected for a half-mask respirator. A panel of 25 subjects with varying face sizes tested 10 models of N95 half-mask filtering-facepiece respirators. The order in which the tests were performed was randomized. Redonning occurred between the tests. Four statistics: sensitivity, predictive value of a pass, specificity, and predictive value of a failure were computed. The sensitivity values ranged from 0.87 to 0.98, the predictive value of a pass from 0.86 to 0.95, the specificity from 0.22 to 0.44, and the predictive value of a failure from 0.33 to 0.43. The best screening test was the corn oil, with 2% of the subjects receiving a false adequate conclusion, followed by the PortaCount (3%), the Companion (13%), and the Bitrex (13%). The Companion and Bitrex methods might not adequately screen out poorly fitting respirators.
Respirators; Respiratory-equipment; Air-purifying-respirators; Equipment-reliability; Performance-capability; Testing-equipment; Materials-testing; Laboratory-testing; Regulations; Personal-protective-equipment; Face-masks; Aerosols; Filters; Filtration; Leak-prevention; Failure-analysis
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American Industrial Hygiene Conference and Exposition, May 20-25, 2000, Orlando, Florida
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division