IEC 60079-0:2011 pdf Explosive atmospheres – Part 0: Equipment – General requirements
1 Scope
This part of IEC 60079 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 80 kPa (0,8 bar) to 1 1 0 kPa (1 ,1 bar); 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”’ (IEC 60079-1 ) or limitation of energy, ‘intrinsic safety “i”’ (IEC 60079-1 1 ).
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 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 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.
NOTE 2 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.
NOTE 3 It is acknowledged that, with developments in technology, it may be possible to achieve the objectives of the IEC 60079 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 IEC 60079 series, may be applied in part. It is intended that the manufacturer prepare documentation that clearly defines how the IEC 60079 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”, IEC 60079-33, is in preparation.
NOTE 4 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.
NOTE 5 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.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60034-1 , Rotating electrical machines – Part 1: Rating and performance
IEC 60034-5, Rotating electrical machines – Part 5: Classification of degrees of protection
provided by the enclosures of rotating electrical machines (IP Code)
IEC 60050-426, International Electrotechnical Vocabulary (IEV) – Chapter 426: Electrical
apparatus for explosive atmospheres
IEC 60079-0:2011 pdf Explosive atmospheres – Part 0: Equipment – General requirements
