Accession Number:

ADA164746

Title:

Hearing Protection against Low Frequency Weapon Noise.

Descriptive Note:

Final rept. 30 Mar 82-30 Jun 83,

Corporate Author:

AUBURN UNIV AL

Report Date:

1983-12-05

Pagination or Media Count:

60.0

Abstract:

This investigation sought to determine the material properties that are responsible for low frequency 100 Hz noise attenuation in foam earplugs. An attempt was made to determine the following for each earlplug type investigated 1 chemical structure 2 energy absorption at low frequencies 3 noise attenuation as a function of foam density and 4 the foam geometry. One experimental foam was found to give good low frequency noise protection but the physical properties responsible are unknown. Earplug materials tested were either polyvinyl chloride or polyurethane. All the commercial plugs contained some extractable plasticizer. Energy absorption was measured on two different dynamic mechanical analysis testers. Density was determined from weight and volume measurements and foam geometry was determined microscopically. Although the properties of foam varied widly, no property was found which gave a reasonable correlation with the foams ability to attenuate low frequency noise. A suggestion is made for the collection of air permeability data, along with the basis for that suggestion. One additonal foam material was found which gave reasonable low-frequency noise attenuation in tests on the laboratory manekin. Keywords Acoustic attenuation.

Subject Categories:

  • Anatomy and Physiology
  • Acoustics
  • Protective Equipment

Distribution Statement:

APPROVED FOR PUBLIC RELEASE