Hazardous Location Fundamentals
The potential for an explosion and/or fire due to the combination of a flammable atmosphere and improper use of electrical equipment makes it essential to understand the regulations, codes and classifications before you purchase the proper equipment. Hazardous locations are classified by electrical code definitions.
The following are interpretations of these classifications and applications.
Class I Locations
Class I locations are those in which flammable gases or vapours are or may be present in sufficient quantities to produce explosive or flammable mixtures.
Class I, Division 1
Class I, Division 1 locations are where hazardous atmospheres may be present during normal operations. It may be present continuously, intermittently, periodically or during normal repair or maintenance operations, or those areas where a breakdown in processing equipment releases hazardous vapours with the simultaneous failure of electrical equipment.
Class I, Division 2:
Class I. Division 2 locations are those in which volatile flammable liquids or gases are handled, processed or used. Normally they will be confined within closed containers or in closed systems from which they can escape only in the case of rupture or deterioration of the containers or systems.
Class II Locations
Class II locations are those that are hazardous because of the presence of combustible dust.
Class II, Division 1
Class II, Division 1 locations include areas where combustible dust may be in suspension in the air under normal conditions in sufficient quantities to produce explosive or ignitable mixtures (dust may be emitted into the air continuously, intermittently or periodically), or where failure or malfunction of equipment might cause a hazardous location to exist and provide an ignition source with the simultaneous failure of electrical equipment. Included also are locations in which combustible dust of an electrically conductive nature may be present.
Class II, Division 2
Class II, Division 2 locations are those in which combustible dust will not normally be in suspension nor will normal operations put dust in suspension, but where accumulation of dust may interfere with heat dissipation from electrical equipment or where accumulations near electrical equipment may be ignited.
In addition to classifying the Class and Division, hazardous locations are also classified by the type of flammable material present. These groups are denoted by Group "X", where "X" is a letter from A thru G. If you'd like to see the full list of chemical groups, please click here.
Evaluating Equipment for Hazardous Environments
In order to assure that the lighting equipment meets the requirements you have determined you need, check the products for approved testing laboratories such as U.L. or CSA listing which outline where the lighting unit, cable, etc. has been tested and approved for use. All tested and listed equipment will be marked for the hazardous locations where they can be used.