FIELD PERFORMANCE-MEASUREMENTS OF HALF-FACEPIECE RESPIRATORS - STUDY PROTOCOL

This article presents the research protocol used for a series of field studies that were conducted to measure workplace protection factors ( WPF) for elastomeric and disposable half-facepiece respirators against particulate contaminants. The protocol was used for studies at three brass foundries, an aircraft painting operation, and a steel mill sint er plant. Particulate contaminants evaluated in these industries-opera tions included various metal dusts and fumes and paint overspray that included metallic pigment. In this article findings are reported on as pects of the sampling and analytical methodology that were employed fo r the first time in these studies. These include (1) collection of WPF samples during different parts of the shift, (2) collection of respir able dust samples, (3) washing of sample cassettes, and (4) use of pro ton induced X-ray emission analysis. Workplace protection factor resul ts measured after the respirator was worn for several hours were gener ally higher than those measured when it was first put on, but the incr ease was nor significant. Results suggest that mixing respirable and t otal dust collection techniques, when determining C-o and C-i, can lea d to errors in estimating WPF. Data from cassette washing suggest that average wall losses for the ambient and infacepiece samples were, res pectively, less than 2% and 6%. Details of WPF data in each operation will be reported in subsequent articles.