Abstract
Carbon tetrachloride has been used for years as a standard material for evaluating charcoal's ability to adsorb organic materials. It has also been the standard organic compound for testing organic vapor breakthrough characteristics of respirator cartridges and canisters. However, due to the potential carcinogenic characteristic of carbon tetrachloride and the lack of commercial availability, a suitable substitute organic vapor cartridge test agent is needed. Four potential replacement agents were tested (ethyl acetate, pentane, n-hexane, and heptane). Initially, testing was performed using the stacked-cartridge test system. This screening method identified replacement agent challenge concentrations which gave breakthrough characteristics equivalent to 1000 parts per million (ppm) carbon tetrachloride. Breakthrough time was the critical criterion. Two test conditions (550 ppm pentane and 1000 ppm n-hexane) were selected for side-by-side testing with 1000 ppm carbon tetrachloride. The results show that for the most stringent test condition (“as received” cartridges tested at 64 L/min and 80% relative humidity) the breakthrough times for two different manufacturers' organic vapor cartridges were identical for these three test conditions (1000 ppm carbon tetrachloride, 550 ppm pentane, and 1000 ppm n-hexane). Pentane's lower toxicity makes it the replacement agent of choice.