Perhaps the most challenging environments to illuminate are hazardous locations, which includes: aircraft hangars, gasoline service stations, bulk storage plants for gasoline or other volatile flammable liquids, paint-finishing process plants, healthcare facilities, agricultural or other facilities where excessive combustible dusts may be present, marinas, boat yards, and petroleum and chemical processing plants.
The National Electric Code (NEC) provides recommendations for electrical installations in hazardous locations, which are areas where there is a potential for fire or explosion. These locations can include areas with flammable gases, vapors, liquids, dust, or fibers. The NEC classifies hazardous locations into three types: Class I, Class II, and Class III.
Class I locations – flammable vapors and gases may be present in quantities that can ignite if they come into contact with open flames or electrical sparks:
Group A: Acetylene
Group B: Hydrogen
Group C: Ethylene
Group D: Propane
Class II locations – combustible dust may be present:
Group E: Metal Dusts
Group F: Carbonaceous Dusts
Group G: Non-Conductive Dusts (these include plastic, wood, grain, flour, etc.)
Class III – the presence of easily ignitable fibers or flyings.
Within these classes, hazardous lighting locations are further broken down into two divisions:
Division 1
The most severe environment, where hazardous atmospheres are always or often present, or become present during frequent servicing or repair. Class 1 Division 1 equipment provides maximum protection in high-risk areas.
Division 2
The hazardous atmosphere is only available infrequently, such as in the case of an accidental spill or the failure of a mechanical positive ventilation system. Class 1 Division 2 equipment offers cost-effective solutions for less hazardous zones.