NEMA Type 9 Enclosures Only for Class II Hazardous Locations?

Currently NEMA only defines Type 9 Enclosures for Class II Hazardous Locations. In contrast, Dusttight enclosures are referenced in NEMA 250 solely for Nonhazardous Locations.(Table 1) This conflicts with NFPA 70 Articles 500 & 502 in addition to the OSHA HazLoc regulation 1910.307 where dusttight enclosures are compliant in Class II Division 2 HazLoc.

Would clarification in future revisions of NEMA 250 assist stakeholders in providing consistency with NFPA 70 Articles 500 & 502 and the OSHA HazLoc regulation regarding dusttight enclosures in Class II Division 2 HazLoc?

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NEMA Enclosures for Nonhazardous & Hazardous Locations

Few inspections made before LNG plant fire:

Investigators also determined that the shop was constructed under building and fire codes that don't allow for work on hazardous materials such as natural gas.

That kind of work falls under an occupancy rating that generally requires encased lighting fixtures and gas monitoring equipment that could have prevented the fire,

via news.tradingcharts.com

Ignition after natural gas contacting an arcing fluorescent light. Electrical fixtures in the destroyed maintenance shop not rated for Hazardous (Classified) Locations (29 CFR 1910.307). State Fire Marshal made an informal tour in May 2008 and didn't observe HazLoc weakness nor at an earlier inspection in the 1990's. Say What?

This story sounds so familiar of state fire marshal's not recognizing combustible dust fire and explosion hazards (explosive atmospheres) as mentioned in the 2006 Chemical Safety Board's Dust Hazard Investigation.

Posted via web from ComDust