Validation of a recommended approach to recirculation of industrial exhaust air -- volume II (lead battery, woodworking metal grinding, and enamel blending operations).
An evaluative supplement to a previous NIOSH publication on the design, installation, and operation of a recirculation system for exhaust air is presented. Evaluations of recently installed recirculating air exhaust systems, including breathing zone, workplace, and in duct contaminant concentrations measurements, were conducted in four facilities, involving lead (7439921) battery assembly, woodworking, wet grinding, and enamel blending. Results of the evaluations were applied retrospectively in accordance with the previously prescribed guidelines to determine whether findings supported or contradicted the recommended approach. Case histories, complete with conclusions and recommendations, are included. Conclusions addressing the overall effectiveness of the original document are detailed. The author recommends further research and development to bridge the gap between theory and practice.