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Determination of known exhalation valve damage using a negative pressure user seal check method on full facepiece respirators.

Authors
Delaney-LJ; McKay-RT; Freeman-A
Source
Appl Occup Environ Hyg 2003 Apr; 18(4):237-243
NIOSHTIC No.
20032393
Abstract
A negative pressure user seal check (NPUSC) method was evaluated for its ability to adequately detect known exhalation valve leakage into a respirator. Three valves with different types of damage were included. Twenty-six test subjects, wearing full facepiece respirators, were asked to perform a NPUSC. Their responses as to whether they passed or failed the user seal check were compared to fit testing results from two quantitative fit test methods: ambient aerosol and controlled negative pressure. In addition, equipment developed at the University of Cincinnati was used to measure in-mask pressures that are generated during the performance of NPUSCs. This technique was employed to assess the ability of respirator wearers to properly conduct user seal checks. The data were analyzed to determine if the user seal check procedure is an effective method for detecting known exhalation valve damage. All test subjects reported passing the user seal check with the undamaged valve. With the warped valve installed, 95 percent of test subjects reported passing the user seal check. With the slit valve installed, 73 percent of test subjects reported passing. With the dirty valve installed, 65 percent reported passing. All fit factors, measured with the damaged valves, were below the Occupational Safety and Health Administration-recognized pass/fail criteria except one fit test with the respirator equipped with the slit valve. Results from the in-mask pressure measurements confirmed whether or not the subject properly conducted a user seal check, but did not detect respirator leakage. In conclusion, the performance of a NPUSC rarely helped to identify damaged exhalation valves. These results support the need for respirator inspection prior to donning with periodic fit testing and the performance of user seal checks as necessary components of an adequate respiratory protection program.
Keywords
Respirators; Respiratory-protective-equipment; Face-masks; Leak-detectors; Failure-analysis; Equipment-reliability; Quality-control; Quantitative-analysis; Standards; Filters
CODEN
AOEHE9
Publication Date
20030401
Document Type
Journal Article
Funding Amount
1070124
Funding Type
Grant
Fiscal Year
2003
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-T42-CCT-510420
Issue of Publication
4
ISSN
1047-322X
NIOSH Division
OD
Source Name
Applied Occupational and Environmental Hygiene
State
OH; GA
Performing Organization
University of Cincinnati
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