Noise reduction at the shooting range by means of level-dependent hearing protectors

Abstract

Background: The aim of the tests was to establish the possibilities of reducing impulse noise by using level-dependent hearing protectors at a shooting range. The tests included 9 models of level-dependent earmuffs and 2 models of level-dependent earplugs. They were conducted in the presence of impulse noise generated by 7 types of firearms (pistols, a submachine gun, rifles, a shotgun). Material and Methods: The tests were conducted at an outdoor shooting range, using an acoustic test fixture that meets the requirements of the ANSI/ASA S12.42-2010 standard. Noise parameters were established for the noise reaching the microphones installed in the ear simulators of the acoustic test fixture: uncovered and protected by the tested hearing protectors. Results: All 11 tested level-dependent hearing protectors allow to satisfactorily (below the exposure limit values) reduce the C-weighted peak sound pressure level and A-weighted maximum sound pressure level parameters of noise produced during shots from the 7 types of firearms included in the study. Moreover, in the most unfavorable case, the permissible number of impulses due to the value of the A-weighted noise exposure level normalized to an 8-h working day parameter exceeds 5000 per day. Conclusions: Level-dependent hearing protectors constitute the appropriate means to protect the hearing of people at a shooting range, while maintaining the functionality of these protection devices to transmit speech signals.

Selection of Earmuffs and Other Personal Protective Equipment Used in Combination

“…The acoustic test fixture GRAS 45CB used in this study is a fairly new solution and so far, it has been used mainly for testing hearing protectors under the conditions of impulsive noise [24,25]. The microphone in real ear (MIRE) [20,21,26,27] method and the above-mentioned REAT method [19,22] have been used more often for testing the impact of OPPE on earmuff attenuation.…”