Engineering Controls for Controlling Wood Dust Exposures During Sanding

High wood dust exposures resulting from the use of hand-held orbital sanding equipment are common in the forest products industry, despite the successful control of such exposures from large, semi-automated equipment (sanders, planers, saws). Exposures associated with manual sanding have been effectively reduced using downdraft tables and sanding equipment fitted with LEV. Downdraft tables, which capture dust by pulling air around the work piece in a downward direction, are effective for small work pieces having a minimum dimension no greater than 8 to 10 inches. Ventilation air for the downdraft table is provided by a small blower and should maintain a minimum face velocity of 100 feet per minute. LEV utilizes a shroud mounted on the orbital sander through which air is pulled by a ventilation source and are effective if the work piece is at least as wide as the shroud. Ventilation for orbital sanders is self generated by an impeller or exhaust air, or through an independent source, typically an industrial vacuum cleaner. An industrial vacuum is recommended, as impeller or exhaust air powered devices cannot maintain a minimum airflow rate 50 CFM and as a result, do not provide adequate dust control. Field based monitoring data has shown downdraft tables and LEV to be effective reducing airborne wood dust exposures by 80 to 90 percent. In addition to presenting field based monitoring data, criteria for the successful design and implementation of engineering dust controls for orbital sanding will be presented.