ANSI/ASA S12.6-2008
This Standard specifies laboratory-based procedures for measuring, analyzing, and reporting thepassive noise-reducing capabilities of hearing protection devices. The procedures consist ofpsychophysical tests conducted on human subjects to determine the real-ear attenuation measured athearing threshold. Two fitting procedures are provided: Method A) trained-subject fit, intended todescribe the capabilities of the devices fitted by thoroughly trained users, and Method B)inexperienced-subject fit, intended to approximate the protection that can be attained by groups ofinformed users in workplace hearing conservation programs. Regardless of test method, theattenuation data will be valid only to the extent that the users wear the devices in the same manner asduring the tests. This Standard does not address issues pertaining to computational schemes or ratingsystems for applying hearing protector attenuation values (see ANSI/ASA S12.68), nor does it specifyminimum performance values for hearing protectors, or address comfort or wearability features.Method A of this Standard corresponds to International Standard ISO 4869-1:1990, Acoustics--Hearing protectors --Part 1: Subjective method for the measurement of sound attenuation, andMethod B corresponds to ISO/TS 4869-5:2006, Acoustics--Hearing protectors-- Part 5: Method forestimation of noise reduction using fitting by inexperienced test subjects.