Development and implementation of procedures for testing and assessing the acoustic properties of hearing protectors in real-world exposure to noise

The concept and methodology of testing real-world acoustic efficiency was experimentally verified in laboratory and in real conditions. 34 different types of earmuffs were tested in a laboratory, in conditions simulating typical industrial indoor conditions. Tests were conducted for 3 test signals: high-, medium- and low-frequency noise. The acquired experience was used to develop a procedure for testing the acoustic properties of earmuffs in real-world exposure to noise. A formula describing expanded uncertainty in estimating real-world efficiency of earmuffs was worked out. A methodology of assessing uncertainty which is implied by dispersion data of measurements carried on at repeatability measurement conditions is presented. This methodology was used in respect to 10 models of earmuffs (4 samples of each).