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Filtration and face-fit characteristics of respirators.
Willeke-K; Myojo-T; Chen-C; Weber-A; Marchioni-R
Ninth Symposium on Aerosol Science and Technology in Conjunction with International Aerosol Seminar and Symposium, Part II, Ota, Japan, August 19-21, 1992, Japan Association of Aerosol and Technology 1992:59-63
The filtration and face fit characteristics of filtering (disposable) respirators were discussed. The results of studies investigating the filtration, face fit, and fit test characteristics of disposable respirators were discussed. Filtration tests performed on surgical masks, selected as an example of a disposable respirator, have shown that they can be penetrated by submicrometer sized aerosols, which in operating rooms and other clinical settings could potentially expose the wearer to aerosolized bloodborne pathogens. Face fit tests have shown that disposable respirators under normal conditions show greater leakage of submicrometer size particles than industrial dust/mist/fume (DMF) respirators. When leaks are added to the DMF respirators, they show a much larger increase in leakage rate than the surgical mask. This is attributed to there being a much larger pressure drop across the DMF respirator. Fit tests have shown that when leaks are placed in the respirators, particles larger than 1 micrometer in size penetrate more readily through DMF respirators than surgical masks despite the fact that disposable masks have a lower filtration quality. The authors suggest that when fit testing disposable respirators, the penetration of the test aerosol be evaluated at high and low flow rates. By computing a fit index (FI), defined as the difference between penetration measured at high and low flow rates, for a respirator with and without a leak, a quantity the ratio of the FI with a leak to an FI without a leak that can be directly related to the fit characteristics of any respirator can be obtained.
NIOSH-Grant; Respirators; Respiratory-protective-equipment; Dust-masks; Industrial-hygiene; Laboratory-testing; Equipment-reliability
Environmental Health University of Cincinnati 3223 Eden Avenue Cincinnati, OH 45267-0056
Respirator Research; Respirators
Ninth Symposium on Aerosol Science and Technology in Conjunction with International Aerosol Seminar and Symposium, Part II, Ota, Japan, August 19-21, 1992, Japan Association of Aerosol and Technology
University of Cincinnati, Cincinnati, Ohio
Page last reviewed: May 5, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division