Environmental control of a large paint booth

The environmental hazard posed by escaping visible clouds of paint was investigated in a factory that manufactures dump truck and earth moving machines. The investigation began when painters complained of eye and throat irritation and noticed solid pieces of paint on their bodies. The paint booth, the paint type, ventilatory system, and airborne xylene (1330207) and white-spirit (8030306) concentrations were measured before and after the investigation. The major constituents of the paint were found to be titanium-oxide (13463677), iron-oxide (1309371), and xylene but these did not exceed the time weighted averages (TWA) of 100 parts per million. The paint was thus of relatively low toxicity. The tolerated values (TV) and TWA for xylene and white-spirit were not exceeded but lachrymatory reactions were observed during spraying operations. The ventilatory survey showed several deficiencies. The input volume was in excess of the extracted volume by about 17 percent, causing discharge through the canvas end curtains of the paint booth. This high input of 23.1 cubic meters was due to the collapsed baffle plate in the main duct. The smoke tube showed badly adjusted louvres in the roof vents causing air streams of high velocity to be sprayed towards the operators. The filter panels in the extraction unit had leaks which reduced the extraction volume. Improvements were made by fitting electrostatic guns and air pressure regulators to improve the spraying performance. Deficiencies in the damaged baffle plate and faulty louvres were corrected and the system operated under close monitoring for 2 weeks. Workers were also supplied with protective goggles, overall, and respirators. Post improvement inspection showed a considerable reduction in the amount of paint solids, xylene, and white-spirit in the atmosphere. The authors conclude that instituting a routine monitoring program at a company that does heavy duty painting can provide relatively safe working conditions for the workers.