ASA 127th Meeting M.I.T. 1994 June 6-10

2pNS8. Limits of exposure to high-intensity impulse noise with a 1.5-ms A duration.

James H. Patterson, Jr.

U.S. Army Aeromed. Res. Lab., P.O. Box 620577, Fort Rucker, AL 36362

Daniel L. Johnson

EG&G Management Systems, Inc., Albuquerque, NM 87119

Over the past several years, the U.S. Army Medical Research and Development Command has sponsored a series of studies to determine the human tolerance limits of exposure to high-intensity free-field impulse noise. These studies have been conducted at the Blast Overpressure Test Site in Albuquerque, NM, by EG&G. The results of these studies for impulses with A-durations of 0.8 and 2.9 ms have been reported previously. In the latest study, human volunteers have been exposed to intensities ranging from 173 to 193 dB SPL with an A duration of 1.5 ms. The number of impulses per exposure was varied from 6 to 100. Hearing protection was worn during all exposures. For 6 impulses and 120 impulses, the safe upper intensity limit was approximately 187 dB peak SPL. For 25 to 100 impulses, the limit was approximately 184 dB SPL. [Work supported by U.S. Army Medical Research & Development Command, Contract DAMD17-88-C-8141.] In the conduct of research where humans were the subjects, the investigator(s) adhered to the policies regarding the protection of human subjects as prescribed by 45 CFR 46 (Protection of Human Subjects).