Organic vapor (OV) respiratory cartridge testing--potential Jonas model applicability

More efficient methods of characterizing organic vapor (OV) respirator performance against the wide range of compounds and environmental conditions found in industrial settings are needed to improve respiratory protection in the workplace. One method, based on Jonas' kinetic model, has potential application for evaluating OV cartridges and more efficiently utilizing available research, testing and certification resources. Jonas has shown that the kinetic adsorption capacity and gas adsorption rate of a small packed charcoal sorbent bed is described by the linear relationship between gas breakthrough time and sorbent weight as predicted by the modified Wheeler equation. This research is based on the hypothesis that characterizing sorbent performance against a reference compound will allow prediction of breakthrough times, and therefore prediction of cartridge life, for other compounds under similar conditions. Baseline data on dried cartridges at dry conditions are presented that demonstrate that the linear relationship between breakthrough time and and sorbent weight that Jonas showed for small sorbent columns also holds when commercially manufactured respiratory cartridges are stacked in series to resemble a packed column of varying bed length and sorbent weight. This suggests the potential applicability of the Jonas model for characterizing and evaluating commercially available OV respirator cartridges.