Ventilation control of lead in indoor firing ranges: inlet configuration and booth and fluctuating flow contributions.
Crouch-KG; Peng-T; Murdock-DJ
Am Ind Hyg Assoc J 1991 Feb; 52(2):81-91
Studies on controlling lead (7439921) exposures at indoor firing ranges were described. Two NIOSH smoke release studies at indoor firing ranges indicated that the ventilation systems did not adequately control lead exposures because of recirculation zones created by barriers and panels near the air inlets above the fronts of the booths that impeded air flow. Attempts were made to correct the situation at one of the firing ranges by extending a dropped ceiling from the bottom edge of the barriers to the downrange edge of the booths. This moved the recirculation zone to a point downrange of the firing line, which reduced lead exposures to below the OSHA standard. Laboratory studies using a full scale mockup of an indoor firing range were conducted to assess the effects of inlet and booth configuration on air flow patterns. The air flow pattern was determined by a smoke release technique. These indicated that installing double pegboard partitions at the air inlets of the booths and utilizing double inlets with air flows alternating between them improved air flow and eliminated formation of eddies and wakes. Introducing a fluctuating flow at air inlets fitted with the double pegboards was the most effective technique for eliminating eddies and wakes. The presence of obstacles between the air inlet and booths created backflows that resulted in eddy and wake formation. The authors conclude that obstructions should be kept out of the air flow path and firing line. Using double pegboard paneled inlets with provision for lateral flow between the panels and fluctuating air flows can significantly reduce lead exposures caused by eddies.
NIOSH-Author; Heavy-metals; Air-flow; Airborne-particles; Ventilation-systems; Simulation-methods; Laboratory-testing; Lead-fumes
American Industrial Hygiene Association Journal