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Abstract:
Most current Damage Risk Criteria (DRC) for human exposure to impulse noise are written in terms of peak pressure as the primary index of the traumatic potential or hazard associated with exposure to an impulse noise. Since the peak pressure is only one of many parameters of an impulse, there is a question whether or not a DRC based on peak pressure can reflect accurately the hazard to hearing posed by impulse noise. The experiments described in this report were designed to determine whether peak pressure is an adequate quantifier for an impulse noise DRC. The general approach was to construct two types of impulse noise with the same Fourier pressure spectrum, but with different peak pressures. This makes it possible to compare the hearing loss and injury resulting from impulses which have the same total energy distributed the same way across frequency, but with different peak pressures. The threshold shift measured during the first few hours after exposure showed systematic variation with both peak pressure and energy level. The permanent threshold shift (20 to 30 days postexposure) and the loss of sensory cells showed strong dependence on energy level, with a less pronounced dependence on peak pressure. These results indicate that peak pressure is not a sufficient indicator of auditory hazard; however, energy alone is not a sufficient indicator either.
| Limitations: |
APPROVED FOR PUBLIC RELEASE |
| Pages: |
219 |
| Report Date: |
APR 86 |
| Contract Number: |
DAMD17-80-C-0109 |
| Report Number: |
A609202 |
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