Engineering Controls Database
Stamping Press – Noise Control Study
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Overview: The case history presented here is one of sixty-one case histories that were published by the National Institute for Occupational Safety and Health (NIOSH) in 1978 as part of an industrial noise control manual [NIOSH 1979]. The case histories are examples of engineering tasks that have been completed not only by professional noise control engineers but also by non-acoustical specialists who used common sense to solve their noise problems. The case histories were chosen primarily because the amount of noise reduction actually achieved was measured. Such engineering results, even if not directly applicable to a specific situation, illustrate general principles that may point the way to a successful result. They are intended to be useful to production and safety engineers, health personnel, and other factory personnel who are not specialists in noise control. Case study: This case history concerns noise emissions caused by operation of a high-speed 290-ton stamping press. Sound levels in the vicinity of the press were high enough to contribute to OSHA noise over-exposures of workers near the press as well as of the press operator. Sound levels were found to be in the 95-dBA to 101-dBA continuous slow meter response, at distances of 15 to 25 ft from the operating press when it was the only noise source operating. (Distances were chosen to represent possible nearby worker locations.) |
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| Hearing loss is one of the most common occupational diseases in America today and the second most self-reported occupational illness or injury. Approximately 30 million workers are exposed to hazardous noise on the job and there are approximately 16 million Americans with noise-induced hearing loss. | |
| The U.S. Gypsum Company decided to install their Acoustisorber™ Industrial Sound Control Panel System around the press, to determine how effective the system would be in reducing sound levels in the shielded positions. The panel system employed consists of 2-ft x 8-ft modules made of hardboard on one face, expanded and flattened metal on the other side, with a mineral fiber absorbent sandwiched in 'between. The absorbent is fully wrapped with a thin heat-shrunk plastic film. Individual panels are joined together by light steel framing to form enclosure walls. The two long walls in this example were suspended on an overhead roller track for access to the press. The installation is open-topped and about 24 ft x 32 ft in size. Walls are 16 ft high, except at one short end where the height was dropped to 8 ft to allow for overhead crane clearance. Material feed and discharge are through openings cut into the short sides of the walls. | |
| NIOSH [1979]. Industrial noise control manual – revised edition. Cincinnati, OH: U.S. Department of Health Education and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, DHEW (NIOSH) Publication No. 79-117. | |
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noise control noise control press operator press operator stamping press stamping press |
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Sound levels at the original measurement locations were reduced by 7 to 14 dB to a maximum of 88 dBA at those locations. (See Figure 1) Enclosure systems need not always be elaborate when moderate amounts of noise reduction are needed, and relatively inexpensive materials can be used. The panels provide more than enough transmission loss, mainly from the hardboard backing, to reduce sound levels by the amount needed. The key is making sure that spillover sound, escaping over the top of the enclosure, through joint leaks, etc., does not short-circuit the transmission loss potential. The absorbent material on the inner surface of the walls minimizes that effect here. [img=1] |