Workplace Protection Factor Evaluation of Respiratory Protective Equipment in a Primary Aluminum Smelter

Abstract

A study was performed at the Arvida Works of Alcan to determine the suitability of a helmeted Powered Air Purifying Respirator (PAPR) in a primary aluminum smelting plant using the horizontal stud Söderberg process. Participants in the test program were worker volunteers drawn from various jobs performed by the anode crews. The research protocol was developed to complement the work methodologies used by Alcan with as little change as possible in their work schedules. Half the crews wore dual cartridge half-mask negative pressure respirators and the other half wore helmeted PAPRs. The dual cartridge half-mask negative pressure respirators were equipped with organic vapors/acid gas cartridges and dust/mist/fumes or dust/mist prefilters; the PAPRs were equipped with organic vapors/HEPA filter cartridges. B(a)P was selected as the measurable contaminant. Under the conditions of this study—that is, strict adherence to the test protocol—we found that 95 percent of the Workplace Protection Factors (also called the 5th percentile) were above 275 for helmeted PAPRs and above 9 for dual cartridge half-mask negative pressure respirators. However, if results under less than ideal worker compliance conditions brought Workplace Protection Factors down by a factor of 10, then the helmeted PAPRs would still provide adequate respiratory protection in this study. The results indicate that the B(a)P concentrations expressed as time-weighted average exposure were significantly less than 0.5 μg/m³ for both types of respirators. Gaboury, A.; Burd, D.H.; Friar, R.S.: Workplace Protection Factor Evaluation of Respiratory Protective Equipment in a Primary Aluminum Smelter. Appl. Occup. Environ. Hyg. 8(1):19-25; 1993.