Changes in API RP500-2012: Combustible liquids and vapors

NFPA 70 defines hazardous (classified) locations. API RP500-2012 establishes examples for the degree and extent for hazardous area classification boundaries around equipment and areas commonly found in petroleum facilities. The role of combustible liquids and combustible liquid-produced vapors is examined in RP500-2012, along with the comparison of their physical properties. Changes involving combustible liquids and liquid-produced vapors are examined in detail between the 2nd and 3rd Editions of API RP500. Changes and additions to examples for hazardous (classified) location boundaries of combustible liquids and combustible liquid-produced vapors are examined. The effects of heating combustible liquids to temperatures at or greater than their flash points will require that they be classified the same as flammable liquids. This is examined in detail. Any interpretations of American Petroleum Institute Recommended Practice 500 are the opinions of individual presenters. Only API staff may issue API-authorized interpretations.