Industrial facilities gain new area classification guidelines

Abstract

Both the United States National Electrical Code (NEC) and the Canadian Electrical Code (CEC) provide special rules for installing electrical equipment in hazardous (classified) locations. Hazardous locations are those locations where fire or explosion hazards may exist due to flammable gases or vapors, flammable liquids, combustible dust, or easily ignitible fibers or flyings. Only Class I materials (gases and vapors) are within the scope of American Petroleum Institute (API) RP500 and RP505. These recommended practices offer those in the petroleum industry an opportunity to standardize area classification drawings-both for drawings using the Division method of area classification and for drawings using the Zone method of area classification. Good engineering judgment must be used with RP500 and RP505, but guidelines provided should minimize differences of classifications by qualified individuals classifying the same or similar locations. This article provides an overview of the two recommended practices including outlines of tables of content, but primarily emphasising the substantive changes and additions.