ANSI/ASA S12.71:2018

This standard specifies methods of characterizing the performance of systems that estimate the real-ear attenuation provided by hearing protection devices (HPDs) on individual wearers. These systems are designated by this standard as field attenuation estimation systems (FAESs). The quality of the estimates is assessed by comparison of FAES data to those from the standard laboratory real-ear attenuation at threshold (REAT) procedure (ANSI/ASA S12.6) for the same fit of the device on an identical group of test subjects. This standard defines ways to quantify and state uncertainty (see JCGM 100:2008) for FAESs so that measurements can be compared among systems and to the standardized REAT procedure.
The criteria in this standard are intended to provide guidance to manufacturers of FAESs in the development of systems and the specification of their performance in a prescribed manner. A further goal is to assure that FAESs provide data that are both useful for estimates of the attenuation obtained by individual wearers and are comparable between systems. This standard does not apply to systems that measure a physical quantity that cannot be linked to an attenuation value.
This standard also specifies the procedures for computation of a personal attenuation rating (PAR) that provides a simple easy-to-apply single number that may be used together with A-weighted sound level measurements for hearing protector assignment.
FAES-derived data do not replace the attenuation data from ANSI/ASA S12.6 or the insertion-loss data from ANSI/ASA S12.42, nor are such data suitable for hearing-protector labeling purposes. FAESs that comply with this standard are not suitable to estimate attenuation for electronic hearing protectors in their active mode, nor for passive amplitude-sensitive HPDs for sound pressure levels above the point at which their level-dependent characteristics become effective. However, PARs may be used to estimate attenuation for passive and non-level-dependent HPDs for impulsive noises up to at least 170 dB peak sound pressure level.