Cartridge service life is not appreciably affected at relative humidities below 50%. However, performance is severely compromised when the humidity exceeds 65%. Experimental values are compared from those calculated from the adsorption isotherm, Mecklenburg and modified Wheeler equations. Calculations indicate that temperature does not play a significant role in service life predictions.

The theory of solvent vapor adsorption of activated carbon is reviewed. Calculated and experimental cartridge service life values are compared using various breathing rates, relative humidities, concentrations and solvent vapors. Cartridge service life (the 10% breakthrough time) can be estimated from the emperical expression: t 10% = 2.4 X 10(6) WC (A + BT)/C 2/3 MQ Carbon weight (wc), relative solvent volatility (a, b and t) concentration (C), molecular weight (M) and breathing rate (Q) all play a vital role in cartridge performance predictions.