WHY ARE SAFETY RATINGS IMPORTANT?
There are several different types of hazardous locations in which it can be extremely dangerous to use any light that has not been specially designed for that kind of location. These are areas where fire or explosion hazards may exist due to the presence of flammable gases, liquids, vapours, dusts or ignitable fibers or flyings.
DIFFERENT LIGHTS FOR DIFFERENT HAZARDOUS LOCATIONS.
The National Electric Code (NEC) defines hazardous locations by “Class” and “Division.” There are three classes:
Class I – Locations are made hazardous by the presence of flammable gases, liquids or vapours.
Class II – Locations are hazardous because combustible dusts are present.
Class III – Locations contain easily ignitable fibers or flyings.
The “Division” designation refers to the likelihood that ignitable concentrations of flammable materials are present. There are two Divisions:
Division 1 designates an environment where ignitable concentrations of flammable gases, liquids, vapours or dusts can exist some of the time or all of the time, under normal operating conditions, or where easily ignitable fibers and flyings are manufactured, handled or used.
Division 2 locations are where ignitable concentrations are not likely to exist under normal operating conditions or where Class 3 materials are stored or handled.
Hazardous classes are further defined by “Groups” based on the physical properties of their combustible materials.
These Groups include (but are not limited to):
Group A – Acetylene
Group B – Hydrogen
Group C – Ethylene, carbon monoxide
Group D – Propane, gasoline, naphtha, benzene, butane, ethyl alcohol, acetone, methane
Group E – Metals including aluminium, magnesium (Div. 1 only)
Group F – Carbonaceous dusts including coal, carbon black, coke
Group G – Dusts not included in E and F including wood, plastics, flour, starch or grain dusts.