Abstract
The high sound pressure level generated by impulse noise produced in an indoor shooting range makes it necessary to protect the hearing of the people it affects. Due to the need for verbal communication during training at a shooting range, level-dependent hearing protectors are useful. The objective of this study was to answer the question of whether it is possible to properly protect the hearing of a shooting instructor using level-dependent hearing protectors. The noise parameters were measured in the places where the instructor was present at the shooting range. The division of a specific group of trained shooters into subgroups consisting of three or six simultaneously shooting individuals did not significantly affect the exposure of the shooting instructor to the noise. An assessment of noise reduction was carried out for eight models of earmuffs and two variants of earplugs, using computational methods for the selection of hearing protectors. Among the noise parameters, both the A-weighted equivalent sound pressure level and the C-weighted peak sound pressure level were taken into account. Depending on the assessment criterion adopted, a sufficient reduction in impulse noise was provided by either four or six out of the 10 hearing protectors included in the study.
Highlights
Impulse noise is dangerous for hearing due to its fast-changing nature
The occurrence of impulse noise is very often associated with the inability to apply engineering measures or administrative methods to reduce noise, which is especially true for people who are inside shooting ranges, where the sound source is in close proximity to the people
In view of the fact that impulse noise is generated at the shooting range, level-dependent hearing protectors are considered as if they were used in passive mode, because the electronic circuits of such protectors block the transmission of sound in the presence of an acoustic impulse
Summary
Impulse noise is dangerous for hearing due to its fast-changing nature. A single exposure to noise produced from an artillery shot can lead to a temporary hearing loss, while repeated exposure to noise associated with gunfire can result in permanent noise-induced hearing loss [1].Auditory dysfunction after the blast results from the loss of outer hair cells and decreased spiral ganglion neurons and afferent nerve synapses [2]. The occurrence of impulse noise is very often associated with the inability to apply engineering measures or administrative methods to reduce noise, which is especially true for people who are inside shooting ranges, where the sound source is in close proximity to the people. It has been found that the effectiveness of suppressors can significantly exceed the noise reduction of hearing protectors [5]. This effectiveness, at a level of 20–28 dB, was determined as not always sufficient [4]. In one of the reported studies, it was found that, despite the fact that suppressors significantly lower the peak sound pressure level (SPL) produced during shots—e.g., from AR-15 rifles—in most cases, its value exceeds 140 dB [6]. Due to the fact that the values of parameters of noise generated by shots most often exceed those that may be harmful to
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