Effects of humidity and contaminant concentration on respirator cartridge breakthrough.
Am Ind Hyg Assoc J 1990 Apr; 51(4):202-209
The original theory of symmetric curves was applied to assess the effect of both humidity and contaminant concentration on respirator cartridge performance. The study emphasized the potential application of the original model to the assessment of the effects of humidity and contaminant assault concentration on contaminant breakthrough in the breakthrough region of approximately 0 to 50%. The study specifically addressed a contaminant range of 250 to 2500 parts per million and a relative humidity range of dry to 80% for the environment in which the respirator was used. The contaminants used in the test were benzene (71432) and methyl-chloroform (71556). The approach assumed that the breakthrough curve for specified conditions of respirator cartridge use was symmetric and sigmoidal. The results of the study demonstrated that the logarithm of the breakthrough time (log-t) was proportional to the logarithm of concentration (log-Ci). The constant of proportionality was the parameter-a. The linear relationship between log-t and log-Ci, the development of associated expressions, and the determination of pertinent values of parameter-a and additional theoretical parameters permits the generation of an entire set of contaminant breakthrough curves, each curve corresponding to a specific contaminant concentration, for a specified test humidity and a given contaminant. If manufacturers of respirators were to provide pertinent values of parameter-a and the additional parameters, for each combination of cartridge type, humidity conditions, and contaminant, the user could evaluate the potential efficacy of respirator cartridge type regarding specific applications.
NIOSH-Publication; NIOSH-Grant; Respirators; Personal-protective-equipment; Respiratory-equipment; Organic-vapors; Respiratory-protective-equipment; Respiratory-protection; Toxic-gases
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American Industrial Hygiene Association Journal
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