1 Scope
This Technical Specification specifies a method for measuring noise reduction of passive hearing protectors at the threshold of hearing . The method is designed to provide estimates of the noise reduction obtained by typical groups of users in real-world occupational settings, who may lack the training and motivation to wear hearing protectors in an optimum manner.
The principle of the test method is to measure the difference in hearing threshold with and without wearing a hearing protector . This difference between the thresholds constitutes the noise reduction. The measurement is done twice on a given number of test subjects.
NOTE 1 The principle of measuring the influence of a hearing protector on the hearing threshold is used in ISO 4869-1 and in this Technical Specification. The method described in ISO 4869-1 yields the sound attenuation of the hearing protector under test. The result of the measurement is a pure physical characteristic of the hearing protector . The method described in this Technical Specification yields the performance of the system as a whole, i.e. the influence of hearing protector , test subjects, fitting and instruction.
This test method yields data that are collected at low sound pressure levels (close to the threshold of hearing ), but which are also representative of the noise reduction values of hearing protectors at higher sound pressure levels. This Technical Specification is i...
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