DEVELOPMENT OF A FIELD METHOD FOR EVALUATING THE SERVICE LIVES OF ORGANIC VAPOR CARTRIDGES—PART III: RESULTS OF LABORATORY TESTING USING BINARY ORGANIC VAPOR MIXTURES

Results of a third study on the use of small, carbon-filled glass tubes, referred to as respirator carbon tubes (RCTs), for predicting the service lives of organic-vapor respirator cartridges are presented. Previous work demonstrated that accurate prediction of cartridge breakthrough time was possible for exposure to carbon tetrachloride in atmospheres containing 5–94% relative humidity (RH) with both “as-received” and prehumidified carbon beds. This report examines the effects of binary organic vapor mixtures and intermittent testing on the predictive accuracy of the method. Results of this study demonstrated the RCT method predicted cartridge breakthrough times to an accuracy of ±17% at the 95% confidence level for n-hexane, pyridine, and binary mixtures of each with carbon tetrachloride in an approximately 50% RH environment. Estimated kinetic adsorption capacities for each adsorbate-carbon bed system tested were reduced when a second adsorbate was introduced at the same concentration. There was no evi...