API Recommended Practice 500, 4th Edition

api500API Recommended Practice 500, 4th Edition. API has published API Recommended Practice (RP) 500, Classification of Locations for Electrical Installations at Petroleum FacilitiesAPI 500: Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class I, Division 1 and API 510: Pressure Vessel Inspection