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Characterizing TWA noise exposures using statistical analysis and normality.

Henry SD
Proceedings: 1992 hearing conservation conference, April 1-4, 1992. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, task order 91-37982, 1992 Apr; :65-68
The characterization of time weighted average (TWA) noise exposures using statistical analysis and normality was discussed. A program and risk assessment method developed at Anniston Army Depot, Alabama, in 1984 to evaluate noise exposure in 2500 employees whose TWAs varied significantly from day to day was discussed. Whether results of a Canadian study that indicated that risk assessments could be made by calculating the probability to equal or exceed an 85 decibels average (dBA) TWA were valid for the depot was investigated. Instead of occupations, work site specific noise exposure populations were identified and daily TWAs were analyzed. The Kilmogorov Smirnov test was applied in the statistical analysis. The probability for this population to be at or above 85dBA TWA was 22%. It was decided that the hearing conservation program would be administered for employees who had a probability greater than 5% (13 days per year) of equaling or exceeding a TWA of 85dBA. From 1984 to 1991, 448 audiodosimeter evaluations of populations from 76 job classifications were carried out. The probabilities of exceeding 81, 85, and 90dBA TWA were calculated using computer methods, for populations of sandblasters and electroplaters, as well as for heavy mobile equipment mechanics and body shop welders. Comparisons for 5 years showed little difference from the original survey. The author concludes that the techniques are usable tools for evaluating variable noise exposures, and provide a means to illustrate long term potential TWA noise exposure at various dBA levels.
Audiometry; Employee-exposure; Hearing-disorders; Industrial-exposures; Occupational-exposure; Industrial-noise; Measurement-equipment; Statistical-analysis; Noise-induced-hearing-loss
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Proceedings: 1992 hearing conservation conference, April 1-4, 1992
Page last reviewed: February 25, 2022
Content source: National Institute for Occupational Safety and Health Education and Information Division