Fit-testing systems for hearing protectors: ANSI standards to the rescue

Abstract

To standardize the performance of fit-testing systems for hearing protection devices (HPDs), an ANSI/ASA standard has been in development since 2008. As of this writing, BSR/ASA S12.71 “Performance criteria for systems that estimate the attenuation of passive hearing protectors for individual users” has been submitted for public comment and ballot. This standard refers to fit-testing systems as field attenuation estimation systems (FAESs). In this talk, we introduce important FAES concepts, as handled in the draft S12.71. There are two types of FAESs: physical systems that take an objective measurement and psychophysical systems that rely on subjective responses from the user being tested. FAESs may produce a quantitative output as a personal attenuation rating (PAR) or simply indicate pass/fail for a given HPD fit. For all types of systems, S12.71 specifies methods to assess the quality of the attenuation estimates, by comparing the FAES results to a laboratory real-ear attenuation at threshold (REAT) measurement. Other important considerations covered in S12.71 include the maximum levels of ambient noise in which FAESs may be operated, the incorporation of uncertainties due to HPD fitting and spectral variability in users’ noise exposures, calibration intervals, and information that must be provided to users.