A Summary of Chipping and Grinding Noise Research at Rensselaer Polytechnic Institute.
Scarton-HA; Kennedy-WC; Caplan-CR; Lacey-JA; Gaylo-KR
NIOSH 1981 Aug:238-252
Work on the control of noise at the source which was carried out at the Rensselear Polytechnic Institute was reviewed, and an analysis was made of the noise generated by a 15,000 revolutions per minute pneumatic horizontal grinder and a pneumatic metal chipping hammer. A new muffler concept was developed and retrofitted to the tested machines. Improvements made in the horizontal extension grinder resulted in the reduction of its free running noise level from 89 to 84 decibels-A (dBA) measured at a distance of 61 centimeters in a room with reverberant noise; the grinding noise of the machine was reduced by 4dBA to 87dBA, while the grinder transient shutoff response declined by 14dBA to 92.5dBA. Noise data recorded for a pneumatic metal chipping hammer were also presented. From a comparison of anechoic data to data recorded during the actual cutting of heavy stock, it was established that the noise from this tool was generated primarily from within the hammer, especially from the chisel. Slow response readings yielded levels of about 106dBA, while peak readings were as high as 128dBA. Mechanical signature analysis of the chipping hammer signal revealed structure borne resonance. The authors state that this problem is under study, and further muffler development for this tool requires answers to the resonance problem.
NIOSH-Contract; Contract-210-79-0048; Noise-sources; Occupational-exposure; Noise-control; Control-methods; Industrial-equipment; Laboratory-testing;
DHHS (NIOSH) Publication No. 81-144
Proceedings of the Symposium on Occupational Health Hazard Control Technology in the Foundry and Secondary Non-ferrous Smelting Industries, December 10-12, 1979, Chicago, Illinois, Division of Physical Sciences and Engineering, NIOSH, U.S. Department of Health and Human Services, Cincinnati, Ohio, DHHS (NIOSH) Publication No. 81-114