Page:NIOSH DM DFM respirator evaluation draft.pdf/45

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  Most QLFT and QNFT protocols are the same as the one used in OSHA's quantitative-fit-test procedure in the lead health standard (29 CFR 1910.1025). TheOSHA protocol is essentially the same as that developed in the early 1970s at the Los Alamos Scientific Laboratory (LASL) for respirator-performance research, which was supported in part by NIOSH. Originally, NIOSH and LASL had hoped to test respirator performance during simulated-workplace use of the respirators. However, as reported in 1976, LASL was unable to accomplish this:

The LASL Human Studies Review Committee's only major objection was to stressing of test subjects. Part of the original test procedure called for test subjects to be stressed by treadmill, while undergoing a quantitative respirator leak evaluation. The purpose of this stressing was to simulate actual workplace use of the respirators. We accordingly abandoned the "stress" portion of the exercises, and substituted a period to be spent in a hot humid chamber, to work up a sweat, as a substitute for physical activity. . . .

The use of the humid chamber was abandoned because of the time pressure on completion of the required number of tests.^[1]

As with the LASL protocol, the current OSHA fit-test protocol does not use a "hot humid chamber, to work up a sweat, as a substitute for physical activity" as LASL intended. Regarding the OSHA test protocol, a noted respirator expert stated in 1990:

The exercise time limits are very short. The required exercises are sedentary and do not replicate movements of workers that may occur in workplaces.^[2]

In 1987, NIOSH cautioned with regard to the efficacy of both qualitative and quantitative fit tests:

No qualitative or quantitative fit tests have been demonstrated to be capable of effectively identifying inadequately fitting respirators (i.e., respirator-wearer combinations that provide less protection than the APF). The presently used tests (e.g., ANSI-recommended, OSHA-approved) may fail to identify individual wearers with inadequate respiratory protection. Thus fit tests should be used with caution and with recognition of their possible deficiencies. As appropriate, periodic

 

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1. Douglas, D. D. et al.: Respirator Studies for the National Institute for Occupational Safety and Health, July 1, 1974–June 30, 1975, Los Alamos Scientific Laboratory Progress Report LA-6386-PR, Los Alamos, New Mexico (August 1976), pp. 35-36.
2. Revoir, W. H.: Comments on OSHA's Proposal to Modify Existing Provisions for Controlling Employee Exposure to Toxic Substances Found in 29 CFR 1910.1000(3) and 29 CFR 1910.134(a)(1). Comments submitted to OSHA (May 30, 1990), p. 20.