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What are hazardous locations?

The determination that areas can be classified as hazardous locations is based on the following:

  • the possible presence of an explosive atmosphere such as flammable gases, vapors, or liquids (Class I), combustible dusts (Class II) or ignitable fibers & flyings (Class III);
  • the likelihood that the explosive atmosphere is present when equipment is operating; and
  • the ignition-related properties of the explosive atmosphere that is present.

This approach to classifying hazardous locations is used by the United States (National Electrical Code), Canada (Canadian Electrical Code), Europe (CENELEC EN60079-10) and throughout the world (IEC 60079-10).

The hazardous locations information provided on these pages is intended to answer questions associated with U.S., Canadian, IEC and European classified hazardous locations.

An area may also be considered "hazardous" for other reasons. These may include the use of electrical equipment in the vicinity of water, the risk of personal injury from moving or falling parts, or even the presence of biological hazards.

While hazards are associated with all of these conditions, areas are only considered hazardous (classified) locations under conditions defined by the NEC, CEC, IEC 60079-10, or CENELEC EN 60079-10, as applicable.

For comments or questions on our hazardous locations site, please contact hazloc@ul.com.