This part of IEC60079 specifies the general requirements for construction, testing and marking of electrical 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 electrical equipment can be operated are: temperature −20°C to +60°C; pressure 80kPa (0,8bar) to 110kPa (1,1bar); and air with normal oxygen content, typically 21% v/v. This standard and other standards supplementing this standard specify additional test requirements for equipment operating outside the standard temperature range, but further additional consideration and additional testing may be required for equipment operating outside the standard atmospheric pressure range and standard oxygen content, particularly with respect to types of protection that depend on quenching of a flame such as ‘ flameproof enclosure “d”’ ( IEC60079‑1 ) or limitation of energy, ‘intrinsic safety “i”’ ( IEC60079‑11 ). NOTE1 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 equipment is −20°C to +40°C, unless otherwise specified and marked. See5.1.1. It is considered that −20°C to +40°C is appropriate for most equipment and that to manufacture all equipment to be suitable for a standard atmosphere upper ambient temperature of +60°C would place unnecessary design constraints. NOTE2 Requirements given in this standard result from an ignition hazard assessment made on electrical equipment. The ignition sources taken into account are those found associated with this type of equipment, such as hot surfaces, mechanically generated sparks, mechanical impacts resulting in thermite reactions, electrical arcing and static electric discharge in normal industrial environments. NOTE3 It is acknowledged that, with developments in technology, it may be possible to achieve the objectives of the IEC60079 series of standards in respect of explosion prevention by methods that are not yet fully defined. Where a manufacturer wishes to take advantage of such developments, this International Standard, as well as other standards in the IEC60079 series, may be applied in part. It is intended that the manufacturer prepare documentation that clearly defines how the IEC60079 series of standards has been applied, together with a full explanation of the additional techniques employed. The designation “Ex s” has been reserved to indicate special protection. A standard for special protection “s”, IEC60079‑33 , is in preparation. NOTE4 Where an explosive gas atmosphere and a combustible dust atmosphere are, or may be, present at the same time, the simultaneous presence of both should be considered and may require additional protective measures. This standard does not specify requirements for safety, other than those directly related to the explosion risk. Ignition sources like adiabatic compression, shock waves, exothermic chemical reaction, self ignition of dust, naked flames and hot gases/liquids, are not addressed by this standard. NOTE5 Such equipment should be subjected to a hazard analysis that identifies and lists all of the potential sources of ignition by the electrical equipment and the measures to be applied to prevent them becoming effective. This standard is supplemented or modified by the following standards concerning specific types of protection: IEC60079‑1 : Gas – Flameproof enclosures \'d\'; IEC60079‑2 : Gas – Pressurized enclosures \'p\'; IEC60079‑5 : Gas – Powder filling \'q\'; IEC60079‑6 : Gas – Oil immersion \'o\'; IEC60079‑7 : Gas – Increased safety \'e\'; IEC60079‑11 : Gas – Intrinsic safety \'i\'; IEC60079‑15 : Gas – Type of protection “n”; IEC60079‑18 : Gas and dust – Encapsulation \'m\'; IEC60079‑31 : Dust – Protection by enclosure “t” IEC61241‑4 : Dust – Pressurization “pD”. NOTE6 Additional information on types of protection for non-electrical equipment can be found in ISO/IEC80079‑36 (to be published). This standard is supplemented or modified by the following equipment standards: IEC60079‑13 : Explosive atmospheres – Part13: Equipment protection by pressurized room“p” IEC60079‑25 : Explosive atmospheres – Part25: Intrinsically safe electrical systems IEC60079‑26 : Explosive atmospheres – Part26: Equipment with equipment protection level (EPL) Ga IEC60079‑28 : Explosive atmospheres – Part28: Protection of equipment and transmission systems using optical radiation IEC62013‑1 : Caplights for use in mines susceptible to firedamp – Part1: General requirements – Construction and testing in relation to the risk of explosion IEC60079‑30‑1 : Explosive atmospheres – Part30-1: Electrical resistance trace heating – General and testing requirements. This standard with the additional standards mentioned above, are not applicable to the construction of electromedical apparatus, shot-firing exploders, test devices for exploders, and shot-firing circuits.