Development of a noise metric for assessment of exposure risk to complex noises.
Zhu-X; Kim-JH; Song-WJ; Murphy-WJ; Song-S
J Acoust Soc Am 2009 Aug; 126(2):703-712
Many noise guidelines currently use A-weighted equivalent sound pressure level LAeq as the noise metric and the equal energy hypothesis to assess the risk of occupational noises. Because of the time-averaging effect involved with the procedure, the current guidelines may significantly underestimate the risk associated with complex noises. This study develops and evaluates several new noise metrics for more accurate assessment of exposure risks to complex and impulsive noises. The analytic wavelet transform was used to obtain time-frequency characteristics of the noise. 6 basic, unique metric forms that reflect the time-frequency characteristics were developed, from which 14 noise metrics were derived. The noise metrics were evaluated utilizing existing animal test data that were obtained by exposing 23 groups of chinchillas to, respectively, different types of noise. Correlations of the metrics with the hearing losses observed in chinchillas were compared and the most promising noise metric was identified.
Exposure-assessment; Exposure-levels; Exposure-methods; Hearing-disorders; Hearing-loss; Laboratory-animals; Laboratory-testing; Noise-exposure; Noise-induced-hearing-loss; Noise-measurement; Occupational-exposure; Risk-analysis; Risk-factors; Standards; Statistical-analysis; Time-weighted-average-exposure;
Author Keywords: acoustic intensity; acoustic noise; acoustic noise measurement; wavelet transforms
Jay H. Kim, Department of Mechanical Engineering, University of Cincinnati, Cincinnati, Ohio 45221-0072
Journal of the Acoustical Society of America
University of Cincinnati