Effects of work conditions simulated in a laboratory environment and wearer fit on attenuation of slow-recovery foam earplugs.
J Sound Vib 1990 Nov; 143(1):153-165
The effects of physical activity and wearer fit on the attenuation performance of slow recovery foam ear plugs were examined. The study group consisted of ten volunteers, five males, mean age 21.5 year. They had normal hearing and had never used foam ear plugs. They inserted foam ear plugs under two conditions: without any guidance other than the instructions on the package (subject fit condition) or with verbal instructions from the experimenter (trained fit condition). They wore the plugs 2 hours while sitting in a chair, performing vigorous temporomandibular movements, or performing a set of simulated industrial jobs that required vigorous upper torso and limb movements. The effects on ear plug attenuation performance were assessed by measuring hearing thresholds over the frequency range 125 to 8000 hertz (Hz) with and without the plugs. The differences in hearing threshold were taken as a measure of attenuation by the ear plug. Ear plug attenuation did not vary significantly with type of activity over the study period. Attenuation performance was significantly improved when the ear plugs were inserted under the trained fit condition compared to the subject fit condition. The improvements ranged from 12 to 14 decibels (dB) at 1000Hz to 3 to 5dB for 2000 to 8000Hz. The authors conclude that when persons are given brief instructions on how to insert slow/recovery foam ear plugs by a qualified individual they improve their level of hearing protection markedly compared to that obtained when the package instructions only are followed. Hearing protection offered by the plugs is not degraded over a 2 hour wearing period or by vigorous physical activity.
NIOSH-Publication; NIOSH-Grant; Noise-induced-hearing-loss; Hearing-protection; Hearing-threshold; Laboratory-testing; Simulation-methods; Work-environment; Psychophysiology; Hearing-tests
Indus Engr and Operations Res Virginia Polytechnic Institute Blacksburg, VA Blacksburg, VA 24061
Journal of Sound and Vibration
Virginia Polytechnic Inst and St Univ, Blacksburg, Virginia