Accession Number : ADA331738

Title :   Pressures Measured Under Earmuffs Worn by Human Volunteers During Exposure to Freefield Blast Overpressures

Descriptive Note : Final rept.,

Corporate Author : EG AND G MANAGEMENT SYSTEMS INC ALBUQUERQUE NM

Personal Author(s) : Patterson, James H., Jr. ; Mozo, Ben T. ; Gordon, Elmaree ; Canales, Jesus R. ; Johnson, Daniel L.

PDF Url : ADA331738

Report Date : AUG 1997

Pagination or Media Count : 106

Abstract : A series of studies to determine the maximum safe exposures to blast overpressure (high intensity impulse noise) were conducted at the Blast Overpressure Test Site on Kirtland Air Force Base, NM, by EG&G Management Systems. Inc., Albuquerque, NM. The studies focused on temporary changes in the threshold of hearing in volunteers wearing earmuffs for hearing protection. From these studies, maximum safe exposure levels have been derived in terms of the parameters of the freefield blast signatures. In collaboration with the contractor researchers at the test site, a field measurement team from the U.S. Army Aeromedical Research Laboratory (USAARL) recorded the pressure signatures under the earmuffs of a subset of the volunteers participating in the studies. These pressure signatures are representative of the effective exposure stimuli arriving at the ears of the volunteers. This report presents the results of these under-the-muff measurements. An analysis of indicators of auditory hazard derived from the pressure-time signatures under the muffs indicated that weighted sound exposure level (SEL) measures and peak levels corrected for B-duration are good indicators of auditory hazard when a correction factor of 1 to 5 dB per 10 fold change in number of impulses is used as the number-intensity trading rule.

Descriptors :   *VOLUNTEERS, *OVERPRESSURE, *BLAST, *EAR PROTECTORS, ARMY RESEARCH, PERFORMANCE(HUMAN), THRESHOLD EFFECTS, TEAMS(PERSONNEL), PRESSURE MEASUREMENT, HIGH INTENSITY, STIMULI, IMPULSE NOISE, HEARING, EAR, SAFETY EQUIPMENT, AVIATION MEDICINE, DEPTH INDICATORS, PRESSURE SIGNATURES.

Subject Categories : Acoustic Detection and Detectors
      Protective Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE