Influence of spray painting parameters on breathing zone particle size distributions.
Appl Occup Environ Hyg 1997 Nov; 12(11):744-750
The effects of spray painting task parameters on breathing zone particle size distribution were examined. A newly developed method, in which droplets were sampled on polycarbonate membrane filters and analyzed microscopically, was used to measure volatile paint mist size distributions. Laboratory breathing zone samples were obtained in a wind tunnel using a mannequin and corn-oil to simulate a spray painting task. Field breathing zone samples were obtained in an actual spray painting booth using either a conventional gun or a high volume, low pressure (HVLP) gun. Nozzle pressure, air to liquid mass flow ratio, and worker orientation to the freestream were varied. In the laboratory, the average geometric mean diameters (GMDs) differed significantly according to worker orientation, equaling 13.5 micrometers (microm) in the 90 degree orientation and 10.9microm in the 180 degree orientation. While nozzle pressure was not a significant influence on the GMDs in the 90 degrees orientation, the GMDs decreased significantly with increasing nozzle pressure in the 180 degrees orientation. Air to liquid mass flow ratio was not a significant factor in either orientation. The overall mass median diameter (MMD) was smaller in the 180 degree orientation than in the 90 degree orientation. The breathing zone MMD was not correlated with the spray MMD. In the field, using the conventional gun, the average GMD in the 90 degree orientation, 8.6microm, was significantly higher than that in the 180 degree orientation, 7.5microm. Using the HVLP gun, the average GMD in the 90 degrees orientation, 9.7microm, was significantly higher than that in the 180 degree orientation, 7.4microm. Nozzle pressure was not a significant influence in either orientation. The MMDs were smaller in the 180 degrees orientation than in the 90 degrees orientation. The authors conclude that worker orientation affects the droplet size distributions of volatile paint mist.
Spray-painting; Breathing-zone; Spraying-booths; Spraying-equipment; Aerosol-particles; Aerosol-sampling; Air-sampling-equipment; Simulation-methods
Environmental Sciences & Engr University of North Carolina CB 7400 Rosenau Chapel Hill, NC 27599-7400
Research Tools and Approaches: Exposure Assessment Methods
Applied Occupational and Environmental Hygiene
University of North Carolina Chapel Hill, Chapel Hill, North Carolina