Review of Influential Factors Affecting the Performance of Organic Vapor Air-Purifying Respirator Cartridges

Abstract

Industrial hygienists must consider numerous diverse factors prior to selecting a respirator. An accurate evaluation of environmental conditions as well as work functions is essential if an organic vapor air purifying device is to be properly chosen. Environmental factors which need careful consideration are oxygen level, contaminant composition, contaminant concentration, contaminant's warning properties, temperature, and relative humidity. In addition, work rate and numerous other work-related factors must be carefully evaluated to assure worker safety. In fact, safety precautions are built into the regulations themselves (30 CFR Part 11) by imposing environmental and use limitations for organic vapor respirator cartridges. These include: 1. not for atmospheres which are immediately dangerous to life and health (IDLH), 2. not for use against gases or vapors with poor warning properties (unless permitted by MSHA/OSHA), and 3. not for use against gases or vapors which generate high heats of reaction with the sorbent. Further, there are concentration limitations for use of an organic vapor chemical cartridge respirator: the IDLH concentration of the specific organic vapors, a maximum use concentration (MUC) of 1000 PPM for organic vapors, and the allowable faceseal and exhalation valve leakages. Chemical cartridge respirators are not approved for use at concentrations above the lower of these three values. Thus, extreme care must be exercised when selecting organic vapor cartridges due to these constraints. It is therefore essential that one be knowledgeable concerning the influential factors affecting cartridge performance. This paper reviews and discusses some critical cartridge performance factors (environmental and other) which must be considered prior to the appropriate selection of an organic vapor air purifying cartridge respirator.