Evaluation of Carbon Tetrachloride Replacement Agents for Use in Testing Nonpowered Organic Vapor Chin-Style Canisters

Abstract

For years, charcoal's ability to adsorb organic compounds has been evaluated employing carbon tetrachloride. The breakthrough characteristics for chin-style canisters against organic vapors mandate the use of carbon tetrachloride as per 30 CFR, Part 11. However, due to carbon tetrachloride's toxicity and the lack of commercial availability, a substitute organic vapor test agent is needed. This article deals with the evaluation of four potential substitute agents (ethyl acetate, pentane, n-hexane, and heptane) for testing chin-style canisters. Screening tests identified replacement agent challenge concentrations that gave breakthrough characteristics similar to 5000 parts per million (ppm) carbon tetrachloride. Side-by-side correlation testing was done between 4000 ppm pentane at 64 L/min, 80 percent relative humidity (RH), and 25°C with the most critical 30 CFR, Part 11 test condition (85% precondition followed by testing at 50% RH, 32 L/min, and 25°C). Finally, a reproducibility study was performed employing the 4000 ppm pentane system. The data show that pentane at 4000 ppm, 80 percent RH, 64 L/min, and 25°C correlated with carbon tetrachloride data, and that the pentane system gives reproducibility test breakthrough times. A pentane testing regimen using “as received” canisters tested at 25, 50, and 80 percent RH at a flow rate of 64 L/min and 25°C can be established to replace the present 30 CFR, Part 11 carbon tetrachloride test criteria for chin-style canisters.