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Noise and Hearing

其他書名	Relationship of Industrial Noise to Hearing Acuity in a Controlled Population
出版	U.S. Department of Health, Education, and Welfare, Public Health Service, 1961
URL	http://books.google.com.hk/books?id=-T9rAAAAMAAJ&hl=&source=gbs_api

註釋The relationship of changes in hearing acuity to long-term exposure to industrial noise was studied in Federal penitentiaries during the period 1953-59 by the Division of Occupational Health of the U.S Public Health Service. The workers studied were employed in textile mills; wood products and sheet metal products manufacturing; brush, shoe, and clothing factories; and printing. Overall noise levels in these operations ranged from approximately 75 to 110 decibels. Men employed in these plants had their hearing tested periodically. A group of approximately 600 men was maintained during the course of the study. Since replacements were made to take care of turnover, data were collected on 1, 952 different individuals during the study. Of these, 1,070 had preemployment audiograms. Approximately 12,000 men had their hearing tested at the time of admission to the penitentiaries. Findings are compared with four well-known proposed sets of criteria. For hearing conservation purposes the findings are in agreement with the recommendations of the Subcommittee on Noise of the American Academy of Ophthalmology and Otolaryngology and Air Force Regulation 160-3. In general, the damage risk criteria proposed by Rosenblith and Stevens for Broad band noise are also confirmed. The theory that narrow band noise requires more stringent criteria is not substantiated by the findings of these studies. Approximately half of commonly encountered industrial noise would be classed as narrow band by this definition. The lower limit of 50 sones per octave band does not always provide sufficient protection.