You are here:
DEGREASING SYSTEM POLLUTION PREVENTION MODIFICATION VS. INDUSTRIAL HYGIENE CONCERNS
Citation:
Darvin, C. AND J. Wander. DEGREASING SYSTEM POLLUTION PREVENTION MODIFICATION VS. INDUSTRIAL HYGIENE CONCERNS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/D-91/196.
Description:
The paper describes using a vapor degreaser at Wright-Patterson AFB to evaluate various modifications to reduce 1,1,1-trichloroethane (TCA) emissions. he modifications included freeboard extension, refrigerated chiller, lip vent removal, covers, and combinations of each. he evaluation was aimed at maintaining a safe industrial hygiene environment. he lip vent, installed to maintain the breathing zone concentration of solvent at below the OSHA PEL (permissible exposure limit), also enhanced the discharge of solvent to the atmosphere. he solvent concentration of the discharge duct averaged 300 ppm solvent during normal operation. reeboard extension reduced emissions by up to 50%, but at the expense of increased breathing zone concentration when the lip vent was off. sing extended freeboard combined with a below-zero freeboard chiller reduced the discharge of solvent by more than 75%, while keeping the breathing zone solvent concentration at 10 ppm and below, although the freeboard fan was turned off. tudy results show that both industrial hygiene and air pollution concerns can be satisfied with proper engineering and operation of the degreasing system. he involved degreaser was a 26 sq ft (2.4 sq m) open-top vapor system. pproximately 93,000 lb (42.222 kg) of TCA solvent is used each year in the system. remodification breathing zone solvent concentration averaged 10 ppm.