Effects of air temperatures and humidities on efficiencies and lifetimes of air-purifying chemical respirator cartridges tested against methyl iodide.
Methyl iodide penetration curves through three types of respirator cartridges and canisters were determined at several temperatures to identify the significance of temperatures of testing and use. Three charcoal types showed similar results: triethylenediamine (5% TEDA-impregnated, (2% TEDA + 5% KI3)-impregnated, and unimpregnated. Penetration curves were shifted at higher temperatures in the range 25-38 degrees C, keeping relative humidity constant in the range 50-70%, but allowing absolute humidities to increase correspondingly. These shifts were such that penetrations were increased and service lives were decreased significantly (4-15% per degrees C). At constant water vapor concentration, service life of the (2% TEDA + 5% KI3)-impregnated charcoal increased with temperature, illustrating the complexity of temperature effects. For one case (5% TEDA) using cartridges at humidity equilibrium, temperature and humidity effects were sorted out. Until these effects are better understood, air-purifying respirator cartridge and canister testing should be done at conditions more representative of possible use and at more closely controlled temperatures.
D006813:Humidity; D006847:Hydrocarbons, Iodinated; D010879:Piperazines; D011482:Protective Devices; D012134:Respiratory Protective Devices; D013696:Temperature
D006847:Hydrocarbons, Iodinated; D010879:Piperazines; C014055:methyl iodide; C007306:triethylenediamine