This part of IEC 60079 specifies the general requirements for construction, testing and
marking of Ex Equipment and Ex Components intended for use in explosive atmospheres.
The standard atmospheric conditions (relating to the explosion characteristics of the
atmosphere) under which it may be assumed that Ex Equipment can be operated are:
• temperature –20 °C to +60 °C;
• pressure 80 kPa (0,8 bar) to 110 kPa (1,1 bar); and
• air with normal oxygen content, typically 21 % v/v.
This part of IEC 60079 and other standards supplementing this standard specify additional
test requirements for Ex Equipment operating outside the standard temperature range, but
further additional consideration and additional testing may be required for Ex Equipment
operating outside the standard atmospheric pressure range and standard oxygen content.
Such additional testing may be particularly relevant with respect to Types of Protection that
depend on quenching of a flame such as ‘flameproof enclosures “d”’ (IEC 60079-1) or
limitation of energy, ‘intrinsic safety “i”’ (IEC 60079-11).
NOTE 1 Although the standard atmospheric conditions above give a temperature range for the atmosphere
of -20 °C to +60 °C, the normal ambient temperature range for the Ex Equipment is –20 °C to +40 °C, unless
otherwise specified and marked. See 5.1.1. It is considered that –20 °C to +40 °C is appropriate for many items of
Ex Equipment and that to manufacture all Ex Equipment to be suitable for a standard atmosphere upper ambient
temperature of +60 °C would place unnecessary design constraints.
NOTE 2 Requirements given in this standard result from an ignition hazard assessment made on equipment. The
ignition sources taken into account are those found associated with this type of equipment, such as hot surfaces,
electromagnetic radiation, mechanically generated sparks, mechanical impacts resulting in thermite reactions,
electrical arcing and static electric discharge in normal industrial environments.
NOTE 3 Where an explosive gas atmosphere and a combustible dust atmosphere are, or can be, present at the
same time, the simultaneous presence of both often warrants additional protective measures. Additional guidance
on the use of Ex Equipment in hybrid mixtures (mixture of a flammable gas or vapour with a combustible dust or
combustible flyings) is given in IEC 60079-14.
IEC 60079 does not specify requirements for safety, other than those directly related to the
Ignition sources like adiabatic compression, shock waves, exothermic chemical reaction, selfignition
of dust, naked flames and hot gases/liquids, are not addressed by this standard.
NOTE 4 Although outside the scope of this standard, such equipment would typically be subjected to a hazard
analysis that identifies and lists all of the potential sources of ignition by the equipment and the measures to be
applied to prevent them becoming effective. See ISO/IEC 80079-36.
This document is supplemented or modified by the following parts and technical specifications:
– IEC 60079-1: Gas – Flameproof enclosures "d";
– IEC 60079-2: Gas and dust – Pressurized enclosure "p";
– IEC 60079-5: Gas – Powder filling "q";
– IEC 60079-6: Gas – Liquid immersion "o";
– IEC 60079-7: Gas – Increased safety "e";
– IEC 60079-11: Gas and dust – Intrinsic safety "i";
– IEC 60079-13: Gas and dust – Equipment protection by pressurized room “p” & artificially
ventilated room “v”;
– IEC 60079-15: Gas – Type of protection “n”;
– IEC 60079-18: Gas and dust – Encapsulation "m";
– IEC 60079-25: Gas and dust – Intrinsically safe electrical systems
– IEC 60079-26: Gas – Equipment with equipment protection level (EPL) Ga
– IEC 60079-28: Gas and dust – Protection of equipment and transmission systems using
– IEC 60079-29-1: Gas detectors – Performance requirements of detectors for flammable
– IEC 60079-29-4: Gas detectors – Performance requirements of open path detectors for
– IEC/IEEE 60079-30-1: Gas and dust – Electrical resistance trace heating – General and
– IEC 60079-31: Dust – Protection by enclosure “t”
– IEC 60079-33: Gas and dust – Special protection “s”
– IEC 60079-35-1: Caplights for use in mines susceptible to firedamp – General
requirements – Construction and testing in relation to the risk of explosion
– IEC TS 60079-39: Gas – Intrinsically safe systems with electronically controlled spark
– IEC TS 60079-40: Gas – Requirements for process sealing between flammable process
fluids and electrical systems
– ISO 80079-36: Gas and dust – Non-electrical equipment for explosive atmospheres –
Basic method and requirements
This document, along with the additional parts of IEC 60079 mentioned above, is not
applicable to the construction of
• electromedical apparatus,
• shot-firing exploders,
• test devices for exploders, and
• shot-firing circuits.