API Publishes 4th Edition of Standard for Classification of Locations for Electrical Installations at Petroleum Facilities
The American Petroleum Institute (API) has published API Recommended Practice (RP) 500, Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class 1, Division 1, and Division 2, 4th edition, for the safe selection and installation of electrical equipment in potentially hazardous environments.
Building off previous editions that date back to 1955, the 4th edition provides guidelines for classifying locations where flammable gases and liquid-produced vapors are present. The critical provisions of this Standard determine requirements for electrical equipment and associated wiring that is appropriate for a particular location, and therefore is essential for use across all major petroleum and natural gas facilities and segments.
The Standard covers petroleum facilities classified as Class 1, Division 1, and Division 2, and electrical equipment that is temporarily or permanently installed. It applies where the presence of flammable gases and vapors present an ignition risk when mixed with air under normal atmospheric conditions.
The 4th edition of API RP 500 introduces several notable updates including the addition of a new section which focuses on the classification of locations at liquefied natural gas (LNG) facilities, including various processes such as refrigeration and liquefaction, storage, and loading/unloading. Additionally, the document incorporates significant revisions of content and figures, adding contemporary relevance and accuracy.
In recognition of its safety benefits, the U.S. Department of the Interior Bureau of Safety and Environmental Enforcement (BSEE) incorporated previous editions of RP 500 in 30 CFR 250, making compliance compulsory for regulated facilities. The importance and value of RP 500 has led to its adoption as a national standard in many countries, including Chile, Equatorial Guinea, India, Indonesia, Mexico, Nigeria, Singapore, and Vietnam.
API RP 500 is complementary to API 505, Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class 1, Zone 0, Zone 1, and Zone 2. While API RP 500 focuses on the division system (as defined by the National Electrical Code), API 505 applies to the zone system.
