1.1 Purpose
The purpose of this Standard is to provide minimum requirements for the design, construction, and
marking of electrical equipment or parts of such equipment for use in Class I and Class II, Division 2 and
Class III, Divisions 1 and 2 hazardous (classified) locations.
This equipment, in normal operation, is not capable of causing ignition of the surrounding atmosphere
under the conditions prescribed in this Standard, although the equipment could contain electronic
components used in an incendive circuit and could also have field wiring that is an incendive circuit.
In addition, it is the intent of this document to establish uniformity in test methods for determining the
suitability of the equipment and associated circuits and components as they relate to potential ignition
of a specific flammable gas or vapor-in-air mixture, combustible dust, easily ignitible fibers, or flyings.
1.2 Applicable to Class I and II, Division 2 and Class III, Divisions 1 and 2 locations
This Standard applies only to equipment, circuits, and components for use in Class I and II, Division 2
and Class III, Divisions 1 and 2 hazardous (classified) locations as defined in the National Electrical Code®
(NEC®), ANSI/NFPA 70, or in the Canadian Electrical Code, Part I (CE Code Part I), CSA C22.1.
Notes:
1) Some equipment designed for use in unclassified locations is permitted by the NEC® or CE Code Part I for
installation in Division 2 locations. The judgment of acceptability for the installation would be determined by
the authority having jurisdiction. Such equipment would not have the hazardous location marking or
documentation described in this Standard. It is anticipated that such equipment would comply with the other
requirements in this Standard and that the determination of compliance is elementary (e.g., a nonarcing
instrument inside a Type 4 or Type 12 enclosure used in a Class II, Division 2 location).
2) Throughout this Standard, references to CAN/CSA-C22.2 No. 60079-0 and ANSI/ISA 60079-0 are made as
“CSA/ISA 60079-0”. Similarly, references to CAN/CSA-C22.2 No. 60079-1 and ANSI/ISA 60079-1 are made as
“CSA/ISA 60079-1”, references to CAN/CSA-C22.2 No. 60079-11 and ANSI/ISA 60079-11 are made as
“CSA/ISA 60079-11”, and references to CAN/CSA-C22.2 No. 60079-15 and ANSI/ISA 60079-15 are made as
“CSA/ISA 60079-15”.
3) The US and Canadian adoptions of IEC 60079-0, IEC 60079-1, IEC 60079-11 and IEC 60079-15 could be
adopted at different revision levels and may have different National Deviations.
1.3 Applicable to associated nonincendive field wiring apparatus
This standard also applies to associated nonincendive field wiring apparatus located in a non-hazardous
(unclassified) location specifically designed to directly connect to nonincendive field wiring in Class I and
II, Division 2 and Class III, Divisions 1 and 2 hazardous (classified) locations.
Note: The 2015 CE Code Part I does not address nonincendive field wiring circuits in Class II or Class III hazardous
locations.
1.4 Applicable ambient conditions
The requirements of this Standard are based on consideration of the following ambient conditions:
a) a lower ambient temperature of -50 °C or higher;
b) an upper ambient temperature of 40 °C or lower;
c) an oxygen concentration of not greater than 21 percent by volume; and
d) a pressure of 80 kPa (0.8 bar) to 110 kPa (1.1 bar).
Note: Equipment specified for atmospheric conditions beyond the above limits could be subject to additional
investigation.
1.5 Not applicable to specified ignition mechanisms
This standard is not applicable to mechanisms of ignition from external sources, such as static electricity
or lightning, that are not related to the electrical characteristics of the equipment.
1.6 Not applicable to specific products
This standard does not apply to electric luminaires for use in Division 2 hazardous (classified) locations.
This standard does not apply to electric motors, electric heaters, heat tracing cables, and similar heatproducing
products, except where they are an integral part of the equipment under evaluation, for use
in Division 2 locations. Where electric motors, electric heaters, heat tracing cables, or similar heatproducing
products are an integral part of the equipment under evaluation, applicable requirements
from the Division 2 hazardous locations standards for these products shall be considered.
In the United States, this Standard does not apply to battery-operated flashlights and lanterns within
the scope of ANSI/UL 783.