With OSHA’s Process Safety Management standard coming up on its 27th birthday, we are seeing companies still grappling with managing their Hazardous Locations (HAZLOC). When the process involves a flammable liquid or gas, it is still fairly common to find a HAZLOC containing permanently installed equipment that is not rated for the HAZLOC. And by equipment, I am not talking about mobile equipment or small components… I mean we still find electrical panels the size of a big screen TV inside the HAZLOCs. And as usual, the facility scrambles to find a solution to abate the recognized hazard; however, often times the abatement falls short of meeting the most recognized RAGAGEP – NFPA 70 (e.g. the National Electric Code). Specifically, I want to discuss the use of purged and pressurized enclosures as a “Protection Technique” as this seems to be the root of evil for many of these facilities who rely on contractors “expert advice” which leads them astray.
NOTE: I am NOT an electrical expert and do not attempt to even install ceiling fans at my home. I hire certified electricians for my electrical work; however, as a safety engineer, I have over 25 years working with NFPA codes related to flammable hazards, specifically HAZLOCs.
So let’s start with what NFPA 70 says about the “Purged and Pressurized Enclosure Protection Technique”…