Comparison of A-weighted Auditory Risk Criteria with Octave-Band Estimates.
Final rept. Nov 70-Mar 71,
SCHOOL OF AEROSPACE MEDICINE BROOKS AFB TEX
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The recent trend toward adoption of A-weighted sound levels to identify degrees of auditory risk has prompted investigations to determine modifications which must be made when applying the A-weighted method to specific noise environments. This report compares recently proposed criteria based on A-weighted sound levels with critical limits based on octave-band data as proposed by Working Group 46 of the Committee on Hearing, Bioacoustics, and Biomechanics of the National Academy of Sciences--National Research Council. The use of C--A as a correction factor to equate dBA levels with octave-band assessments is discussed. Noise conditions within the cockpits of fixed- and rotary-wind aircraft were used as the basis for the comparisons. Results indicate that use of A-weighted sound levels for estimating potentially hazardous exposures of the type encountered in aircraft must be approached with caution for two reasons 1 Spectrum content of a given noise influences the degree of auditory risk associated with single values of dBA, and 2 the relationship between duration and intensity of noise is curvilinear, rather than linear as assumed by the Walsh-Healey Act provisions. Author
- Stress Physiology