HAZ AREA IEC 60079 Hazardous Area Classification Objectives


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As per IEC 60079-10-1 Clause 4.2
Area classification is a method of analysing and classifying the environment where explosive gas atmospheres may occur so as to facilitate the proper selection and installation of equipment to be used safely in that environment. The classification also takes into account the ignition characteristics of the gas or vapour such as ignition energy (gas group) and ignition temperature (temperature class).
In most practical situations where flammable materials are used, it is difficult to ensure that an explosive gas atmosphere will never occur. It may also be difficult to ensure that equipment will never give rise to a source of ignition. Therefore, in situations where an explosive gas atmosphere has a high likelihood of occurring, reliance is placed on using equipment which has a low likelihood of creating a source of ignition. Conversely, where the likelihood of an explosive gas atmosphere occurring is reduced, equipment constructed with less rigorous requirements may be used.
Below is a simplistic diagram to classify hazardous areas as per IEC 60079.

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Scope Of IEC 60079 Series of Standards

IEC 60079 specifies the general requirements for construction, testing and marking of electrical equipment and Ex Components intended for use in explosive atmospheres.
Th IEC 60079 series of standard types of protection:
  • IEC 60079-1: Gas – Flameproof enclosures "d"
  • IEC 60079-2: Gas – Pressurized enclosures "p"
  • IEC 60079-5: Gas – Powder filling "q"
  • IEC 60079-6: Gas – Oil immersion "o"
  • IEC 60079-7: Gas – Increased safety "e"
  • IEC 60079-11: Gas – Intrinsic safety "i"
  • IEC 60079-15: Gas – Type of protection "n"
  • IEC 60079-18: Gas and dust – Encapsulation "m"
  • IEC 60079-31: Dust – Protection by enclosure "t"
  • IEC 61241-4: Dust – Pressurization "pD".
Additional information on types of protection for non-electrical equipment can be found in ISO/IEC 80079-36 (to be published). This standard is supplemented or modified by the following equipment standards:
  • IEC 60079-13: Explosive atmospheres – Part 13: Equipment protection by pressurized room "p"
  • IEC 60079-25: Explosive atmospheres – Part 25: Intrinsically safe electrical systems
  • IEC 60079-26: Explosive atmospheres – Part 26: Equipment with equipment protection level (EPL) Ga
  • IEC 60079-28: Explosive atmospheres – Part 28: Protection of equipment and transmission systems using optical radiation
  • IEC 62013-1: Caplights for use in mines susceptible to firedamp – Part 1: General requirements – Construction and testing in relation to the risk of explosion
  • IEC 60079-30-1: Explosive atmospheres – Part 30-1: Electrical resistance trace heating – General and testing requirements.
Excluded equipment under IEC 60079:
  • electromedical apparatus,
  • shot-firing exploders,
  • test devices for exploders, and
  • shot-firing circuits.