Chamber for Testing Asbestos-Containing Products: Validation and Testing of a Re-created Chrysotile-Containing Joint Compound

Abstract

Joint compound products containing chrysotile asbestos were commonly used for building con-struction from the late 1940s through the mid-1970s. Few relevant data exist to support recon-structing historical worker exposures to fibers generated by working with this material. Therefore, we re-created 1960s-era chrysotile-containing joint compound (JCC) and compared its characteristics to a current-day asbestos-free joint compound (JCN). Validation studies showed that a bench-scale chamber with controlled flow dynamics, designed to quantify partic-ulate emissions from joint compound products, provided precise and reliable measurements of generated airborne dust mass, chrysotile fiber concentrations, and corresponding activity-specific emission rates. Subsequent chamber studies characterized fibers counted by phase con-trast microscopy (PCM) per mass of respirable dusts and total suspended particulate dusts (total dusts), generated during JCC sanding or sweeping, as well as corresponding dust emission rates for JCC and JCN, and the ratio of total to respirable dust mass for JCN. From these data we estimated factors, FCH-rd and FCH-td (in units of f cm 23 per mg m23), by which respirable JCN dust mass concentrations collected during construction use can be converted to correspond