Survey report: control technology evaluation for controlling worker exposure to asphalt fumes from roofing kettles: kettle operated using an afterburner system at 5900 Broadway, San Antonio, Texas, report no. CT-231-16a.
On August 30 and 31, 2000, a field survey was conducted at a construction site where a built up asphalt roof was being installed on an addition to a strip mall building at 5900 Broadway Avenue in San Antonio, Texas. The survey was conducted to evaluate the effectiveness of using an afterburner system with a safety loading door fitted to an asphalt kettle to reduce worker exposure to asphalt fumes. Personal breathing zone and area air samples were collected and analyzed for total particulate (TP), benzene soluble fraction (BSF) of the TP, and total polycyclic aromatic compounds (PAC). These three analyses were chosen to represent indices of exposure to asphalt fumes. Air samples were collected under three different scenarios: afterburner on and kettle lid closed; afterburner off and kettle lid closed; and afterburner off and kettle lid opened. Air samples were collected on the kettle operator, two roof level workers, and area air samples were collected around the four corners of the kettle. The kettle operator's exposures to TP, BSF, and total PAC were all reduced when the afterburner was on and the kettle lid was closed when compared to when the afterburner was off and the kettle lid was opened. Reductions in exposures for the kettle operator of 40%, 60%, and 66% for TP, BSF, and total PAC, respectively, were measured. Reductions of 76%, 84%, and 85% in TP, BSF, and total PAC, respectively, were measured for the area air samples collected around the kettle. For the roof level workers, exposures to TP, BSF, and total PAC were reduced 10%, 23%, and 14%, respectively. None of the reductions measured were statistically significant (p less than or equal to 0.05). The greatest reductions in asphalt fume exposure occurred when the afterburners were on and the kettle lid was closed. Using the afterburner system with the kettle lid closed provided the most protection from asphalt fume exposure, particularly for the kettle operator.
National Institute for Occupational Safety and Health, Division of Applied Research and Technology, Mail stop R-5, 4676 Columbia Parkway, Cincinnati, OH 45226