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Hazardous Locations HAZLOC Explained

Areas are divided into Class 1 Class 2, and Class 3. There are two divisions within each area.

Class, Division, and Groups Explained

Class I

Class I: Gases or vapors. Class I hazardous areas may contain flammable vapors or gases in quantities large enough to cause a fire or an explosion. Examples of these gases and vapors include hydrogen, carbon monoxide, and ethylene oxide.

Class II

Class II: Dust. Class II hazardous areas may contain combustible or conductive dust in quantities large enough to cause a fire or an explosion. Examples of these dusts include metal dusts such as aluminum dust or carbon-based dusts such as coal dust.

Class III

Class III: Fibers. Class III hazardous areas may contain fibers and small airborne parts in quantities large enough to ignite and cause a fire or an explosion. Examples of these include wood, plastic, and grain.

Division 1

Div. I High-Probability locations are defined as an area where the amount of combustible dust is either suspended in the air or accumulated on surfaces in a sufficient concentration to allow for ignition.

All day production would usually be Div. 1.

Division II

Div. II Low Probability locations are usually defined as maintenance areas, or intermittent production.

HAZLOC Groups Explained