An evaluation of wet and dry methods for decreasing exposure to refractory ceramic fibers (RCF) during grinding and sanding.
Dunn-K; Cecala-A; Shulman-S; Cleary-J; Venturin-D; Chen-S; Treadway-J
American Industrial Hygiene Conference and Exposition, May 20-25, 2000, Orlando, Florida. Fairfax, VA: American Industrial Hygiene Association, 2000 May; :48
A cooperative research study is being performed by researchers at NIOSH and the Refractory Ceramic Fibers Coalition (RCFC) to determine cost effective methods for lowering worker exposure to RCFs. The results of sampling at manufacturing and downstream plants have shown that many of the highest documented exposures were encountered in the finishing (grinding, sanding, and sawing) of RCF products. A preliminary study was conducted to evaluate the potential for wet and dry control methods to reduce worker exposure during grinding and sanding. A series of test runs were carried out at NIOSH's Pittsburgh Research Laboratory. The local exhaust ventilation (LEV) consisted of two hoods, while the wet control method consisted of a simple compressed air atomization nozzle directed at the RCF product during machining. A series of test runs were performed according to the following sequence: 1) LEV on; 2) water mister on; and 3) control off. Personal breathing zone and area samples were collected during each 10-minute trial run. Grinding data and sanding data were analyzed as two separate experiments. For grinding, the personal breathing zone (BZ) concentrations showed a 99% reduction for LEV relative to no control and a 88% reduction with water mist relative to no control. Overall, both comparisons are statistically significant at the 5% level. For belt sanding, the personal BZ concentrations showed a 99% reduction for LEV relative to no control and a 42% reduction with water mist relative to no control. At the 5% significance level, the LEV reduction is statistically significant, but the water mist is not. The results of this study may be useful in developing controls that can be used by both the manufacturer and downstream RCF customers.
Refractories; Ceramic-materials; Ceramics; Fibrous-bodies; Employee-exposure; Sampling; Grinding-equipment; Control-methods; Ventilation-systems; Exhaust-ventilation; Exhaust-hoods; Machine-operators; Breathing-zone; Control-technology
American Industrial Hygiene Conference and Exposition, May 20-25, 2000, Orlando, Florida
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