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A control strategy matrix for the autobody repair industry: spray painting autobody parts in a down draft hood.

Yacher JM; Wallace M; Heitbrink W; Hoermann T
American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia. Fairfax, VA: American Industrial Hygiene Association, 1998 May; :53-54
As part of product stewardship partnership for the autobody repair industry, an exposure control strategy for the autobody refinishing industry has been developed. The objective of this strategy is to keep worker exposure to polyisocyanates below 1mg/m3, which is the limit recommended by the paint manufacturers. This strategy recommends half-face piece respirators when automobiles are painted in a properly operated and maintained down draft spray painting booth. Prior work has shown that the use of these booths results in lower paint overspray exposures than other booths when spray painting whole vehicles. However, excess exposures still occur when painting individual autobody parts. Prior data collections indicated that painting parts suspended from the ceiling caused paint overspray to be dispersed throughout the booth and that an air purifying respirator was not likely to be sufficiently protective. For parts painting off the car, a better approach is to place the part on a saw horse at waist height. This painting technique was simulated with the paint spray gun operated with compressed air only. Smoke tube traces indicated that the paint overspray would stay out of the worker's breathing zone. The jet from the spray painting gun moves air parallel to the floor until the jet's energy is dispersed. The air then moves toward the exhaust grates in the floor of the booth. Experimental work was done in a paint manufacturer's test and refinishing training facility to evaluate whether total paint overspray concentrations could be maintained below 10 mg/m3 during autobody parts painting operations. The worker used an HVLP (high ve1ocity, low pressure) spray gun with gravity feed to paint four autobody parts at a time, all positioned on sawhorses, in a down draft booth. Both color base coats and clear coats were applied to each autobody part. Personal sampling for total particulates was performed with both open and closed filter cassettes; charcoal tubes were used to sample for solvents, notably n-butyl acetate. Additionally, area sampling for total particulate was performed using eight-stage impactors. Airflow in the down draft booth appeared to carry the paint overspray away from the painter and his breathing zone and into the floor exhaust grates.
Spray-painting; Spraying-booths; Spraying-equipment; Automobile-repair-shops; Automotive-industry; Employee-exposure; Exposure-assessment; Engineering-controls; Control-equipment; Control-methods; Control-technology; Paint-shops; Paint-spraying; Paints; Exposure-levels; Isocyanates; Respirators; Respiratory-equipment; Respiratory-protective-equipment; Breathing-zone; Exhaust-ventilation; Motor-vehicle-parts; Sampling; Particulates; Air-flow; Acetates; Particle-aerodynamics
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American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia
Page last reviewed: April 1, 2022
Content source: National Institute for Occupational Safety and Health Education and Information Division