In an effort to better characterize airborne fiber levels associated with the installation of residential insulation and to determine the proportion of airborne fibers that are glass fibers, airborne fiber concentrations were measured during the installation of several Owens-Corning Fiberglas insulation products. Sample collection and fiber counting procedures followed National Institute for Occupational Safety and Health Method 7400 with some modifications to allow identification of the fiber type. The arithmetic mean concentration of total airborne fibers during installation of batt-type insulation was 0.22 fibers per cubic centimeter (f/cc) (95% confidence limits of 0.18-0.27 f/cc). Significantly, approximately 60% of these total fibers were glass fibers and approximately 20% were respirable glass fibers. For applications of blowing wool, the total airborne fiber concentrations were higher, with means of 1.0 f/cc (0.9-1.1) or 2.1 f/cc (15-2.7), depending on the product type. Glass fibers were 0.7 f/cc (0.6-0.8) or 1.7 f/cc (1.2-2.5) and respirable glass fibers were 0.3 f/cc (02-0.4) or 0.8 f/cc (05-1.3). Similar to the batt installation results, only 20-40% of the total airborne fibers were respirable glass fibers. The night after installation of the insulation was complete, the airborne fiber concentrations dropped to the levels measured before the insulation work began.

• IAQ: particulate, dust,
• insulation