Suitability of Commercially Available Systems for Individual Fit Tests of Hearing Protectors

摘要

Hearing protector attenuation is measured according to the REAT method given by ISO 4869-1. This method relies on optimum fitting under laboratory conditions and group statistics to predict an individual wearer's hearing protector performance. The consequence is that there has been an emergence of commercially available systems that offer the capability of individual fit testing of hearing protectors in the field to control how much attenuation each individual user will actually experience. The purpose of this paper is to appraise these methods. Four commercially available systems were used under laboratory conditions to assess the performance of two ear-muffs, 4 pre-formed or foam ear-plugs and 2 custom molded ear-plugs for at least 20 test subjects. Results were compared to REAT attenuations (obtained for the same group of subjects) and also to attenuations obtained from MIRE (ISO 11904-1). Three of the four systems provided mean attenuations close to the benchmark values. For these three systems, individual comparisons are acceptable in terms of personal attenuation rating, although discrepancies with REAT individual can be improved. Thus, these systems can be used to validate the hearing protection choice as long as a 10 dB safety margin is considered.