Earplug fit-testing system applying pure-tone audiometer

Abstract

As for the sound attenuation measurement method of hearing protectors, such as earplugs and earmuffs, the real-ear attenuation at threshold (REAT) method is established by some standards such as ISO, ANSI, AS, etc. As known, however, sound attenuation differences between workers wearing protectors in real occupational noise fields are not small due to personal size-fitness or wearing conditions of hearing protectors. Although personal hearing protector fit-testing systems have been developed and standardized in Western countries, the systems have not yet been standardized in Japan, so they are not applicable easily. The authors tried to apply the pure-tone audiometric system equipped with circumaural earphones used for a medical check-up to the fitting system for earplugs on this occasion, where the Japanese guidelines for preventing noise-induced impairments were revised for the first time in about 30 years. This paper describes the overview of the earplug fit-test system applying the audiometer and trial test results of sound attenuation ratings by the proposed system.