A proposal for a more refined single number rating system for hearing protector attenuation specification.
From a study of recent hearing protector attenuation test data, this work presents a proposal to reconsider how data, gathered by recognized standard subjective test procedures, is used to calculate the single number performance rating of hearing protectors. Current practice is to embed the expected performance (mean) and the variation in performance (standard deviation) in a single rating figure. A proposal is made for clearly separating expected performance from the variation while retaining the use of the current subjective test procedures. This proposal is applicable to all current single number rating systems including SNR, NRR, SLC(80), and the newer ANSI NRS(Ax).
Senior Research Engineer, National Acoustic Laboratories, Chatswood, NSW 2067, Australia. warwick.williams@nal.gov.au
Warwick
W
Williams
D001315:Australia; D004430:Ear Protective Devices / Q000592:standards*; D004867:Equipment Design; D006317:Hearing Loss, Noise-Induced / Q000517:prevention & control*; D006801:Humans; D008422:Materials Testing; D009520:New Zealand