QUESTION 1

1. The maintenance manager of your facility has asked you to evaluate a particular welding booth

that utilizes a local exhaust ventilation (LEV) system to remove the contaminant at the source.

The exhaust system does not appear to be drawing enough of the welding fumes away from the

employees to reduce the iron oxide below the permissible exposure limit (PEL) of 10 mg/m³.

During your investigation, you determine that the diameter of the duct system is 8 inches and has

an air velocity of 350 fpm (feet per minute). The welding operation is performed at a distance of

1.5 feet from the exhaust opening. Determine the flow rate, and provide your recommendations

on the control measures that could improve the capture of the iron oxide contaminant.