An exploratory study of moderate physical activity and selected design attribute effects on earmuff attenuation.
Hearing protective devices are tested for their attenuation characteristics under controlled laboratory conditions. Unfortunately, these tests overestimate the typical attenuation performance of the devices in the field, posing the possibility of inadequate protection for the user. Many factors may affect achieved in-field attenuation. This research investigated the influence of the user's work-related movement and variations in headband compression force and earcup cushion material (liquid- or foam-filled) on the frequency-specific noise attenuation achieved with earmuffs. Real-ear attenuation at threshold (REAT) testing procedures were used to collect attenuation data on 24 subjects both prior to and following completion of a simulated work task. Statistical analyses indicated that moderate work-related movement significantly decreased low-frequency attenuation but by only a small amount (1.5 dB at 125 Hz). A high headband compression force was found to increase attenuation by approximately 1.5 to 4 dB at 125, 250, 500, and 8000 Hz. There was no significant difference at any frequency between cushion types. The results indicate a small effect of moderate physical work activity on hearing protector effectiveness and illustrate the importance of certain earmuff design parameters to achieved attenuation.
Casali
J G
JG
Auditory Systems Laboratory, Virginia Polytechnic Institute and State University, Blacksburg.
Grenell
J F
JF
D004430:Ear Protective Devices; D004867:Equipment Design; D005260:Female; D006309:Hearing; D006801:Humans; D008297:Male; D005082:Physical Exertion; D011482:Protective Devices