The effectiveness of local exhaust ventilated (shrouded) hand power tools used for grinding/sanding composite materials

The effectiveness of one particular shrouded tool type in capturing composite dust generated during dry machining operations was tested. The effectiveness of the shrouded tool was measured by comparing exposures during identical operations done by the same worker. The operation was conducted by dividing the time into two equal portions, one using an unshrouded tool and the other with same tool shrouded. The operations included sanding and grinding operations of fibrous glass/epoxy composite materials. Unshrouded short-term exposures ranged from 2.17 mg/m(3) to 50.81 mg/m(3). There was a significant reduction in exposure using the shroud (paired t-test, p=0.005). The effect of a shroud on respirable dust exposures was inconclusive, because of the limited amount of respirable dust collected in these short-term samples.