I have written about the confusion within many industries about their “electrical classification” and what the Recognized and Generally Accepted Good Engineering Practices (RAGAGEPs) allow and do NOT allow. In 2012 we even came across facilities that were using codes from an entirely different industry being applied to their facility, which utilized an entirely different class of flammable material. In this article, I will use the two most popular codes, API 500 and NFPA 497, and touch on using ASHRAE 15. But let me state this upfront, NEITHER API nor NFPA allow an area to be “unclassified” merely by installing ventilation; ASHRAE 15 DOES permit the exclusion of an electrically classified machinery room, BUT it is not a BLANKET EXCLUSION as many have come to believe.
HAZLOCs and Ventilation and Classification
