Abstract
Size-selective gravimetric sampling was conducted along with sampling by impinger for dust in 22 foundries. Three-hour personal samples were taken with a 10-mm cyclone to remove nonrespirable dust, and with a polyvinyl chloride membrane filter to collect a dust sample for weighing. Respirable free silica was determined on samples passing a horizontal elutriator. The evaluation of the potential silicosis hazard by a gravimetric limit was not inconsistent with judgment of the hazard based on impinger samples and the present ACGIH Threshold Limit Value. Size-selective gravimetric sampling is recommended as an alternative to impinger sampling.