evaluations of the effectiveness of each respirator during use in the workplace should be conducted to ensure that each wearer is being provided with adequate respiratory protection.[1]
NIOSH has concluded that this 1987 statement continues to best summarize the questionable efficacy of QLFTs and QNFTs. NIOSH also concluded that the OSHA fit-test protocol (and those similar to it) represents, at best, respirator wearers undergoing no physical activity and no rapid motions of the head. That is, at best the protocol is representative only of sedentary use of a respirator.
NIOSH has concluded that the Hyatt/LASL approach for determining class APFS
for air purifying respirators contains a critical assumption that has not been satisfac-
torily substantiated and must be considered questionable. The Hyatt/LASL approach
assumes that the required proper fit testing conducted by a respirator wearer's
employer will be 100% efficient at identifying those prospective wearer's who cannot
achieve a given APF. However, NIOSH concluded that proper fit tests are not 100%
efficient at identifying those prospective wearer's who cannot achieve a given APF.
At this time there is insufficient evidence to provide reasonable assurance of their
efficacy. Thus any of these fit tests should be selected by respirator-program admin-
istrators and utilized by fit-test operators with due caution and appreciation of their
possible deficiencies. Respirator wearers should be explicitly informed that these fit
tests may fail to identify individual wearers with inadequately-fitting respirators.
NIOSH concluded that the Hyatt/LASL approach for determining APFs embodies a
basically sound requirement. That is, that 100% of respirator users in the workplace
must attain protection exceeding a class APF after proper fitting (i.e., fit testing) has
been performed by the employer. Meeting this requirement is a technical matter of
developing proper fit test methodologies, whether they be quantitative or qualitative,
that can adequately screen out those prospective wearers that are incapable of
achieving an adequate fit with a given respirator.
NIOSH has concluded that due to excessive face-seal leakage, while wearing air-
purifying, NIOSH-certified respirators in the workplace as part of a state-of-the-art
respirator program, from less than 1% to substantially more than 10% of American
workers will not achieve with their respirator facepieces the APF-level protection
computed according to the recommendations of Hyatt/LASL. This is because current-
ly available quantitative and qualitative fit tests have not been satisfactorily demon-
strated to be capable of effectively identifying (screening out) those wearers with
Qualitative or quantitative fit testing accepted by OSHA or generally considered acceptable for
professional practice.
- ↑ NIOSH Respirator Decision Logic, DHHS (NIOSH) Publication # 87-108, Cincinnati, OH (May, 1987), p. 2.
