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TJ-7 1.04.17
What Are Hazardous Location Divisions?.
In NEC Article 500, 501, 502, and 503, Class I, II, and III locations are further broken down into Divisions. The simplified version of a Division for a given Class will be either:

  • Division 1: The ignitables are significantly present under normal conditions.

  • Division 2: The ignitables are significantly present under abnormal conditions.
DIVISION 1 DEFINED AS:
A hazardous location in which ignitables are significantly present in the air in normal conditions in sufficient quantities to be explosive or ignitable, such as petroleum refineries, aircraft hangars, dry cleaning plants, utility gas plants or storage areas for liquefied petroleum or natural gas, and spray finishing areas.
DIVISION 2 DEFINED AS:
A hazardous location in which ignitables are not normally present in in the air in sufficient quantities to be explosive or ignitable. For example: Closed storage drums containing flammable liquids in an inside storage room would not normally allow the hazardous vapors to escape into the atmosphere. But if one of the storage containers spills over and dumps liquid on the floor, or is old and leaking, you've got an abnormal condition.

Abnormal condition: Spilled flammable liquid
Abnormal Condition:


Spilled flammable liquid.
Next: What are Hazardous Location Groups? (Journal #8)
Bill Nagengast, President and Lighting Engineer, Solas Ray Lighting, holds over 20 patents in the lighting industry.
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Information provided in these Journals is prepared by Solas Ray to assist users in reading and understanding NEC codes and standards. The information provided, however, are not Formal Interpretations issued pursuant to NEC Regulations. Any opinions expressed are the personal opinions of the author(s), and do not necessarily represent the official position of the NEC or its Technical Committees. In addition, the responses are neither intended, nor should be relied upon, to provide professional consultation or services.