Document DvGZydMBRxN7Ky12Q1rVQxO05

NOISE CLASSIFICATIONS For descriptive purposes, it is possible to categorize noise exposures in terms of the approximate effect on a group of workers. As a result of the data analysis of a large number of surveys, we have grouped noise exposures in the following four classifications. CLASSIFICATION A - Severe Exposures - Whenever the noise levels in any octave band above (but not including) the 150 to 300 cycle per second band are in excess of 105 decibels, we may expect that the majority of personnel exposed to such noise for a working period of from 10 to 20 years will have sufficient hearing loss to cause slight difficulty in understanding normal speech. CLASSIFICATION B - Moderate Exposures - Whenever the noise levels in any octave band above (but not including) the 150 to 300 cycle per second band are between 95 and 105 decibels, we may expect that a significant percentage of workers exposed to such noise for a working period of from 10 to 20 years will have sufficient hearing loss to cause slight difficulty in understanding normal speech. CLASSIFICATION C - Marginal Exposures - Whenever the noise levels in any octave bands (but not including) the 150 to 300 cycle per second band are between 85 and 94 decibels, we may expect that the rare noise sensitive worker exposed to such noise for a 10 to 20 year period will have sufficient hearing loss to cause sl%ht difficulty in understanding normal speech. CIASSIFICATI0N D - No Exposure - Noise levels below 85 decibels are not hazardous. Even after a lifetime in such an environment, it is unlikely that hearing loss will be incurred. While the classifications will be of value as a guide in evaluating exposures, it should be remembered that the decibel groupings are based upon relatively constant exposure over an 8 hour day. -LIBERTY MUTUAL INSURANCE COMPANY SPNY 000389