AIRBORNE GLASS-FIBER CONCENTRATIONS DURING MANUFACTURING OPERATIONS INVOLVING GLASS WOOL INSULATION

In order to better characterize airborne fiber concentrations arising in manufacturing operations that use glass wool insulation, and to det ermine 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 insu lation, manufactured housing, pipe insulation, kitchen ranges, air-han dling ducts, and water heaters. Some operations in which pipe insulati on and ceiling boards were removed and discarded were also measured. S ample collection and fiber-counting procedures followed National Insti tute for Occupational Safety and Health Method 7,400 procedures (phase contrast light microscopy), with some modifications to allow identifi cation of the fiber type. The arithmetic mean concentration of total a irborne fibers during 11 different manufacturing operations ranged fro m 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 board s, the mean concentration of total airborne fibers was 0.29 fibers/cm3 (95% confidence limits 0.20-0.41 fibers/cm3), whereas the mean respir able airborne fiber concentration was only 0.042 fibers/cm3 (0.023-0.0 59).