API RP 500-1991 Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities (First Edition; Supersedes RP 500A@ RP 500B@ RP 500C)
This document applies to the classification of locations for both temporarily and permanently installed electrical equipment@ The suitability of locations for the placement of non-electrical equipment is not within the scope of this document. Piping systems used for odorized natural gas used as fuel for cooking@ heating@ air conditioning@ laundry and similar appliances are also beyond the scope of this document. A possible catastrophe such as a well blowout or a process vessel rupture is not covered; such an extreme condition requires emergency measures at the time of occurrence. Recommendations for determining the degree and extent of classified locations for specific examples of situations commonly encountered in petroleum facilities are given in Sections A@ B@ and C. While it is important for area classifications at refineries@ production and drilling facilities@ and pipeline facilities to agree to some extent@ there are differences in production@ drilling@ transportation and refining facilities - accounting for@ at least in part@ that three different documents were prepared originally. Some differences include the types and quantities of products handled@ the physical size of typical facilities@ and varying housing/shelter practices. Section A is applicable to Iocations in which flammable petroleum gases and volatile flammable liquids are processed@ stored@ loaded@ unloaded@ or otherwise handled in petroleum refineries. Section B is applicable to locations surrounding oil and gas drilling and workover rigs and facilities on land and on marine fixed and mobile platforms where flammable petroleum gas and volatile liquids are produced@ processed (for example@ compressed)@ stored@ transferred (for example@ pumped)@ or otherwise handled prior to entering the transportation facilities. Section C is applicable to onshore and offshore facilities handling the delivery of flammable or combustible petroleum liquids or flammable gases. Pipeline facilities may include pump and compressor stations@ storage facilities@ manifold areas@ valve sites and pipeline rightof- way areas.
API RP 500-1991 history
2023API RP 500-2023 Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class I, Division 1, and Division 2
2012API RP 500-2012 Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class I@ Division 1 and Division 2 (Third Edition; ERRATA: JANUARY 2014)
1997API RP 500-1997 Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class I@ Division 1 and Division 2 (Second Edition; Errata 10/17/1998)
1991API RP 500-1991 Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities (First Edition; Supersedes RP 500A@ RP 500B@ RP 500C)
1957API RP 500-1957 Recommended Practice for Classification of Areas for Electrical Installations in Petroleum Refineries (Second Edition)
1955API RP 500-1955 RECOMNIENDED PRACTICE FOR CLASSIFICATION OF AREAS FOR ELECTRICAL INSTALLATIONS IN PETROLEUM REFINERIES (FIRST EDITION)