KeywordsHealth Sciences, Occupational Health and Safety.
Health Sciences, Public Health.
AdvisorGerba, Charles P.
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractRespirators are used to minimize the exposure to air contaminants. A good fit is essential for the effective functioning of a respirator. The Occupational Safety and Health Administration (OSHA) requires an annual respirator fit testing. Respirator fit can be assessed either qualitatively or quantitatively. Two studies were conducted to assess the fit testing program with specific objectives to: (1) assess leak rates in full and half mask respirators; (2) assess the effectiveness of "feedback"1 on the quality of fit; (3) evaluate the effect of daily beard growth on respirator leak rates. In the first study, it was found that the half mask respirator has a significantly lower leak rate than the full face respirator. A significant reduction in leak rate in both respirator types with "feedback" was also observed. The finding that half mask respirators have lower leak rates directly contradicts American National Standard Institute's (ANSI) guidelines of higher Assigned Protection Factor (APF) for full mask respirator. Further studies are necessary to determine these findings and to amend respirator recommendations in the future. As expected in the second study, beard growth was associated with respirator leak rate. The effect of daily growth on leak rate over a period of twelve days could be defined by a second order regression equation. An attempt was made to describe some characteristics of beard that affect the leak rate. After 12 days of beard growth, it was found that the aspect ratio (length/diameter) of hair was inversely correlated with leak rate (r = 0.64). 1Feedback: A numerical value measuring the minimum leak rate that can be gotten from a respirator fitting with a normal donning.
Degree ProgramGraduate College
Soil, Water and Environmental Science