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Collection of Silica and Asbestos Aerosols by Respirators at Steady and Cyclic Flow.

PB90154691

Publication Date	1990
Personal Author	Brosseau, L. M.; Ellenbecker, M. J.; Evans, J. S.
Page Count	36
Abstract	Experiments were described which evaluated the predictive ability of tests using a silica (7631869) aerosol under conditions of steady flow for determining respiratory efficiency. Measurements taken of silica penetration at steady flow were reasonably predictive of silica penetration under cyclic flow. Mass penetration of silica under continuous flow conditions was typically less than 0.1 percent. In general, the penetration of silica under conditions of cyclic flow was about one and a half times as great as that measured under steady flow conditions. However, the same was not true for testing with asbestos (1332214) fibers under steady versus cyclic flow. Furthermore, the potential for exhalation valve failure under cyclic flow was also identified. The study indicates that these results call for a reevaluation of the current NIOSH protocols for evaluating respirator performance. The authors urge the development of a NIOSH testing method for evaluating the life cycle performance of respirator components such as exhalation valves.
Keywords	Asbestos Aerosols Silicon dioxide Respirators Protectors Flow rate Air flow Filters Dust Air pollution Respiration Predictive value of tests CAS 7631-86-9 CAS 1332-21-4
Source Agency	National Institute for Occupational Safety and Health
NTIS Subject Category	95G - Protective Equipment 68A - Air Pollution & Control 41I - Job Environment 94D - Job Environment
Corporate Authors	Harvard School of Public Health, Boston, MA. Dept. of Environmental Science and Physiology.; National Inst. for Occupational Safety and Health, Cincinnati, OH.; Lowell Univ., MA.
Supplemental Notes	Prepared in cooperation with Lowell Univ., MA. Sponsored by National Inst. for Occupational Safety and Health, Cincinnati, OH.
Document Type	Technical Report
NTIS Issue Number	199008

Collection of Silica and Asbestos Aerosols by Respirators at Steady and Cyclic Flow.

Collection of Silica and Asbestos Aerosols by Respirators at Steady and Cyclic Flow.
PB90154691

Publication Date	1990
Personal Author	Brosseau, L. M.; Ellenbecker, M. J.; Evans, J. S.
Page Count	36
Abstract	Experiments were described which evaluated the predictive ability of tests using a silica (7631869) aerosol under conditions of steady flow for determining respiratory efficiency. Measurements taken of silica penetration at steady flow were reasonably predictive of silica penetration under cyclic flow. Mass penetration of silica under continuous flow conditions was typically less than 0.1 percent. In general, the penetration of silica under conditions of cyclic flow was about one and a half times as great as that measured under steady flow conditions. However, the same was not true for testing with asbestos (1332214) fibers under steady versus cyclic flow. Furthermore, the potential for exhalation valve failure under cyclic flow was also identified. The study indicates that these results call for a reevaluation of the current NIOSH protocols for evaluating respirator performance. The authors urge the development of a NIOSH testing method for evaluating the life cycle performance of respirator components such as exhalation valves.
Keywords	Asbestos Aerosols Silicon dioxide Respirators Protectors Flow rate Air flow Filters Dust Air pollution Respiration Predictive value of tests CAS 7631-86-9 CAS 1332-21-4
Source Agency	National Institute for Occupational Safety and Health
NTIS Subject Category	95G - Protective Equipment 68A - Air Pollution & Control 41I - Job Environment 94D - Job Environment
Corporate Authors	Harvard School of Public Health, Boston, MA. Dept. of Environmental Science and Physiology.; National Inst. for Occupational Safety and Health, Cincinnati, OH.; Lowell Univ., MA.
Supplemental Notes	Prepared in cooperation with Lowell Univ., MA. Sponsored by National Inst. for Occupational Safety and Health, Cincinnati, OH.
Document Type	Technical Report
NTIS Issue Number	199008