Abstract
In order to better characterize airborne fiber concentrations arising in manufacturing operations that use glass wool insulation, and to determine the proportion of these fibers that are glass fibers, airborne fiber concentrations were measured in a number of different operations involving Owens-Corning Fiberglas insulation products. The operations sampled included those that fabricate or assemble metal building insulation, manufactured housing, pipe insulation, kitchen ranges, air-handling ducts, and water heaters. Some operations in which pipe insulation and ceiling boards were removed and discarded were also measured. Sample collection and fiber-counting procedures followed National Institute for Occupational Safety and Health Method 7400 procedures (phase contrast light microscopy), with some modifications to allow identification of the fiber type. The arithmetic mean concentration of total airborne fibers during 11 different manufacturing operations ranged from 0.02–0.2 fibers/cm3, of which typically half or less were identified as glass fibers. The mean concentrations of glass fibers ranged from 0.002–0.14 fibers/cm3, whereas respirable glass fibers were from 0.001–0.07 fibers/cm3. For the removal of pipe insulation and ceiling boards, the mean concentration of total airborne fibers was 0.29 fibers/cm3 (95% confidence limits 0.20–0.41 fibers/cm3), whereas the mean respirable airborne fiber concentration was only 0.042 fibers/cm3 (0.023–0.059).