Respirator cartridge efficiency studies: VIII. summary and conclusions

Abstract

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.

Quantitative Evaluation of the Effect of Moisture Contents of Coconut Shell Activated Carbon Used for Respirators on Adsorption Capacity for Organic Vapors

“…They used vapors at concentrations of 300-1,000 ppm and at relative humidities of 5 and 85%. Their results are slightly different from those of Nelson et al [3][4][5] , in that particularly in adsorption of trichloroethylene vapor at low concentrations, the moisture effect was not negligible even at relative humidities below 50%. That is, all levels of relative humidity could affect the lifetimes of the carbon beds of their specimens.…”

“…Later, in the 1970s, Nelson et al reported [3][4][5] the effects of the above mentioned influencing factors on adsorption capacity of activated carbon for many kinds of organic vapor in detail. The measurements in their reports were carried out using both petroleum and coconut shell activated carbons for comparatively high concentrations of organic vapors (1,000 ppm).…”

“…Nelson et al stated that petroleum activated carbon was increasingly being used for economic reasons 5) . At present, coconut shell activated carbon is assumed to be affected by moisture content more than petroleum activated carbon [3][4][5] , and further analysis of this point in detail is desirable. Moreover, relative humidity varies significantly from season to season in indoor atmospheres without air-conditioning in Japan.…”

“…Among these influencing factors, moisture content has been the focus of many quantitative researches, and there are many reports [1][2][3][4][5][6][7][8][9][10][11][12][13][14] regarding its effect on the gas filters of respirators or experimental packed beds of activated carbon at room temperature (approximately at 293-298 K).…”

Revising Organic Vapour Respirator Cartridge Change Schedule: a Case Study of a Paint Plant in Iran

“…Nelson et al (5) determined the service life for organic vapour cartridges for a wide variety of air fl ow concentrations, air fl ows, humidity and temperatures (6), and solvent vapour concentrations (7). They also presented an empirical model for estimating cartridge service life (8).…”