CLC/TC 31 - Electrical apparatus for explosive atmospheres - General requirements

Creating an amendment on European level to mirror the IEC interpretation sheet of IEC 60079-1:2014/ISH1:2020 which is still active at IEC.

This part of the IEC 60079 series applies to users and covers only those factors directly related to the inspection and maintenance of electrical installations specifically designed for hazardous areas, where the hazard may be caused by explosive gas or explosive dust atmospheres. It does not include: - other fundamental installation and inspection requirements for electrical installations; - the verification of electrical equipment; - protection or ventilation of rooms; - gas detection systems; - the repair and overhaul of explosion protected equipment (see IEC 60079-19). While this standard does not include inspection of safety devices such as used in ventilated rooms (see 60079-13), this standard does include the requirements for inspection and maintenance of individual items of equipment that will be part of such systems, for example motors or sensors. This standard supplements the requirements for inspection and testing in non-hazardous areas in IEC 60364-6. NOTE 1 Standards applied at the date of installation might not have been IEC standards. This standard is intended to be applied where there can be a risk due to the presence of explosive gas or dust mixtures with air or combustible dust layers under normal atmospheric conditions. It does not apply to: - underground mining areas, - dusts of explosives, - pyrophoric substances.

This document refers to UGLDs (ultrasonic gas leak detectors) that work in a frequency beyond the audible range. This document is applicable to fixed ultrasonic gas leak detection equipment intended to provide an indication, alarm or other output function for the purpose of initiating automatic or manual protective action(s). This document specifies general requirements for design, testing and performance, and describes test methods that apply to UGLD. The following items are considered in this document: - Leak rates to be used to verify the detection range of UGLD, - Test gas to be used (nitrogen or compressed air), - Nozzle shape and size used at all tests leak rate tests, - Gas pressure used at all leak rate tests, - Time duration of each leak rate test, - Test leak nozzle height from solid ground, - Test leak nozzle angling relative to test UGLD, - UGLD angle relative to the leak (field of coverage of the UGLD), - Wind speed and direction, air temperature and humidity at day of test, - Minimum distance to solid structures (walls, etc.) at test site, - Installation height relative to the ground, - Texture of solid ground between leak and UGLD, - Background noise sources, known to interfere with UGLDs, - Specification of detection radius in 3 dimensions, - Operational requirements such as temperature, vibration, etc. This document is also applicable when an equipment manufacturer makes any claims regarding any special features of construction or superior performance that exceed the minimum requirements of this document. This document prescribes that all such claims are verified, and that the test procedures are extended or supplemented, where necessary, to verify the claimed performance. The additional tests are agreed between the manufacturer and test laboratory and identified and described in the test report. This document does not apply to portable gas detectors using ultrasonic measurements nor to gas detectors using non-ultrasonic measurements to detect a gas leak.

This document specifies general requirements for design, testing and performance, and describes the test methods that apply to portable, transportable and fixed equipment for the measurement of the oxygen concentration in gas mixtures indicating up to 25 % (v/v).

IEC Corrected version

IEC 60079-19:2019 gives instructions, principally of a technical nature, on the repair, overhaul, reclamation and modification of equipment designed for use in explosive atmospheres; it is not applicable to maintenance, other than when repair and overhaul cannot be disassociated from maintenance, neither does it give advice on cable entry systems which may require a renewal when the equipment is re-installed. This fourth edition cancels and replaces the third edition published in 2010 together with Amendment 1:2015. This edition constitutes a technical revision. The significance of the changes between IEC 60079-19, Edition 3 (2010), including Amendment 1 (2015), and IEC 60079-19, Edition 4 (2019) are defined in the foreword and cover minor and editorial changes, extension, and major technical changes.

This part of IEC 62990 specifies general requirements for design, function and performance, and describes the test methods that apply to portable, transportable, and fixed equipment for the detection and concentration measurement of toxic gases and vapours in workplace atmospheres and other industrial and commercial applications. This document is applicable to continuously sensing equipment whose primary purpose is to provide an indication, alarm and/or other output function the purpose of which is to indicate the presence of a toxic gas or vapour in the atmosphere and in some cases to initiate automatic or manual protective action(s). It is applicable to equipment in which the sensor generates an electrical signal when gas is present. This document applies to two types of equipment: • Type HM (Health Monitoring) ‘occupational exposure’ equipment: For occupational exposure measurement, the performance requirements are focused on uncertainty of measurement of gas concentrations in the region of Occupational Exposure Limit Values (OELV). The upper limit of measurement will be defined by the manufacturer in accordance with 4.2.1. • Type SM (Safety Monitoring) ‘general gas detection’ equipment: For general gas detection applications (e.g. safety warning, leak detection), the performance requirements are focused on alarm signalling. The upper limit of measurement will be defined by the manufacturer according to the intended use of the equipment. In general, the requirements for accuracy will be higher for Type HM equipment than for Type SM equipment. The same equipment may meet the requirements of both Type HM and Type SM. For equipment used for sensing the presence of multiple gases this document applies only to the detection of toxic gas or vapour. This document is not applicable to equipment: - with samplers and concentrators such as sorbents or paper tape having an irreversible indication; - used for the measurement of gases and vapours related to the risk of explosion; - used for the measurement of oxygen; – used only in laboratories for analysis or measurement; - used only for process measurement purposes; - used in the domestic environment; - used in environmental air pollution monitoring; - used for open-path (line of sight) area gas measurement; - used for ventilation control in car parks or tunnels.

This part of IEC 62990 specifies general requirements for design, function and performance, and describes the test methods that apply to portable, transportable, and fixed equipment for the detection and concentration measurement of toxic gases and vapours in workplace atmospheres and other industrial and commercial applications. This document is applicable to continuously sensing equipment whose primary purpose is to provide an indication, alarm and/or other output function the purpose of which is to indicate the presence of a toxic gas or vapour in the atmosphere and in some cases to initiate automatic or manual protective action(s). It is applicable to equipment in which the sensor generates an electrical signal when gas is present. This document applies to two types of equipment: - Type HM (Health Monitoring) ‘occupational exposure’ equipment: For occupational exposure measurement, the performance requirements are focused on uncertainty of measurement of gas concentrations in the region of Occupational Exposure Limit Values (OELV). The upper limit of measurement will be defined by the manufacturer in accordance with 4.2.1. - Type SM (Safety Monitoring) ‘general gas detection’ equipment: For general gas detection applications (e.g. safety warning, leak detection), the performance requirements are focused on alarm signalling. The upper limit of measurement will be defined by the manufacturer according to the intended use of the equipment. In general, the requirements for accuracy will be higher for Type HM equipment than for Type SM equipment. The same equipment may meet the requirements of both Type HM and Type SM. For equipment used for sensing the presence of multiple gases this document applies only to the detection of toxic gas or vapour. This document is not applicable to equipment: - with samplers and concentrators such as sorbents or paper tape having an irreversible indication; - used for the measurement of gases and vapours related to the risk of explosion; - used for the measurement of oxygen; – used only in laboratories for analysis or measurement; - used only for process measurement purposes; - used in the domestic environment; - used in environmental air pollution monitoring; - used for open-path (line of sight) area gas measurement; - used for ventilation control in car parks or tunnels.

IEC 60079-25:2020 contains the specific requirements for design, construction and assessment of intrinsically safe systems, Type of Protection “i”, intended for use, as a whole or in part, in locations in which the use of Group I, II or III Ex Equipment is required. This document supplements and modifies the general requirements of IEC 60079-0 and the intrinsic safety standard IEC 60079-11. Where a requirement of this standard conflicts with a requirement of IEC 60079-0 or IEC 60079-11, the requirement of this standard takes precedence. The installation requirements of Group II or Group III systems designed in accordance with this standard are specified in IEC 60079-14. This third edition cancels and replaces the second edition published in 2010 and constitutes a technical revision.

IEC 60079-31:2022 is available as IEC 60079-31:2022 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 60079-31:2022 is applicable to equipment protected by enclosure and surface temperature limitation for use in explosive dust atmospheres. It specifies requirements for design, construction and testing of Ex Equipment and Ex Components. This document supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this document conflicts with a requirement of IEC 60079-0, the requirement of this document takes precedence. This document does not apply to dusts of explosives, which do not require atmospheric oxygen for combustion, or to pyrophoric substances. This document does not apply to Ex Equipment or Ex Components intended for use in underground parts of mines as well as those parts of surface installations of such mines endangered by firedamp and/or combustible dust. This document does not take account of any risk due to an emission of flammable or toxic gas from the dust. This third edition cancels and replaces the second edition published in 2013. This edition constitutes a technical revision. Main significant changes from the previous edition are: 1) Document has been restructured from edition 2 2) Fault current rating of interrupting contacts in clauses 4.3.1 and 4.4.1, major change type C1 3) Cells and batteries in clauses 4.3.5.1 and 4.4.5.1, major change type C2 4) Overload or malfunction condition for the determination of temperature class for "tb" converter fed rotating electric machines, major change type C3 5) Additional requirements for entry devices with dust ignition protection by enclosure "t", major change type C4 Information about the background of ‘Major Technical Changes’ C1 – Ex Equipment having Level of Protection "ta" shall be rated for connection to a circuit with a prospective short circuit current of not greater than 1.5 kA. For Ex Equipment having Level of Protection "tb" or "tc" which is intended for mains connection and intended to interrupt fault current above 10kA, the equipment shall have a rated maximum short circuit withstand current, be tested according to 6.1.1.1, and be marked according to Clause 7. C2 – For Ex Equipment having Level of Protection "ta" which contains a cell or battery, only a sealed cell or battery shall be used. For Ex Equipment having Level of Protection "tb" and "tc" where there are sparking contacts or hot surfaces, and which contains a cell or battery, only a sealed cell or battery shall be used. C3 – Table 2 now includes malfunction conditions for temperature class determination of Level of Protection "tb" converter-fed electric machines. C4 – Annex A added for entry devices with Type of Protection "t" including cable transit devices.

This document specifies general requirements for design, testing and performance, and describes the test methods that apply to portable, transportable and fixed equipment for the measurement of the oxygen concentration in gas mixtures indicating up to 25 % (v/v). The equipment, or parts thereof, may be intended for use in explosive atmospheres (see 4.1) and in mines susceptible to firedamp. This document applies to equipment intended for monitoring oxygen deficiency and enrichment. EXAMPLE Monitoring oxygen deficiency and/or enrichment includes: - protection of human health and safety in potentially oxygen deficient atmospheres; - fire protection by monitoring areas with reduced oxygen concentration; - fire protection by monitoring oxygen concentrations exceeding that of normal ambient air. This document also applies to equipment with an oxygen measuring function for explosion protection in the case of monitoring inertisation. NOTE 1 Inertisation is an explosion protection technique where a potentially explosive atmosphere is purged with inert gas. NOTE 2 Commonly used oxygen sensors in commercial equipment for industrial application are: - electrochemical sensors (aqueous and solid electrolytes); - paramagnetic sensors; - zirconium dioxide sensors; - tunable diode laser absorption spectroscopy sensors (TDLAS). This document is applicable to equipment intended to measure reliably the oxygen concentration, to provide an indication, alarm or other output function, the purpose of which is to give a warning of a potential hazard and, in some cases, to initiate automatic or manual protective action(s), whenever the level exceeds or falls below an alarm set point. This document is applicable to equipment, including integral sampling systems of aspirated equipment, intended to be used for commercial, industrial and non-residential safety applications. This document does not apply to external sampling systems, or to equipment of laboratory or scientific type, or to medical equipment, or to equipment used only for process monitoring and/or control purposes. For equipment used for sensing the presence of multiple gases, this document applies only to the measurement of oxygen. This document is also applicable to equipment using optical principles (e.g. TDLAS), where the optical transmitter and receiver or the optical transceiver (i.e. combined transmitter and receiver) and a suitable reflector are not located in a common enclosure. However, in this case it will be necessary to modify the test conditions described in Clause 5.3 and to introduce supplementary tests to Clause 5.4 of this document. Such supplementary tests will include alignment, beam block fault, long range operation. Guidance to appropriate modification of the test conditions and supplementary tests can be taken from EN 60079 29 4. Modifications of the test conditions as well as modified and supplementary tests are expected to be agreed between the manufacturer and test laboratory and identified and described in the test report.

EN 60079-29-1 specifies general requirements for construction, testing and performance, and describes the test methods that apply to portable, transportable and fixed equipment for the detection and measurement of flammable gas or vapour concentrations with air. The equipment, or parts thereof, is intended for use in explosive atmospheres and in mines susceptible to firedamp. EN 60079-29-1 is applicable to flammable gas detection equipment with a measuring range up to any volume fraction as declared by the manufacturer, and which is intended to provide an indication, alarm or other output function; the purpose of which is to indicate a potential explosion hazard and in some cases, to initiate automatic or manual protective action(s).

NEXT ACTION: TB ACTION BY 2020-01-31 (prep doc for BT meeting - Feb2021)
BT CONSULTATION FAILED (addition of Annex ZZ) ON 2020-11-10
HAS CONSULTANT ASSESSMENT BY 2020-09-24 (PUB assessment) - Compliant assessment on 2020-09-22
2020-04-8 mah: Consultant assessment at FV missing, Annex ZZ did not go to FV.

NEW!IEC 60079-15:2017 is available as IEC 60079-15:2017 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 60079-15:2017 specifies requirements for the construction, testing and marking for Group II electrical equipment with type of protection “n” which includes; sealed devices “nC”, hermetically sealed devices “nC”, non-incendive components “nC” and restricted breathing enclosures “nR” intended for use in explosive gas atmospheres. This part of IEC 60079 applies to electrical equipment where the rated input voltage does not exceed 15 kV r.m.s. AC or DC including where the internal working voltages of the Ex product exceeds 15 kV, for example starters for HID luminaires. This part of IEC 60079 supplements and modifies the general requirements of IEC 60079-0, except as indicated in Table 1 (Clause 1). Where a requirement of this part of IEC 60079 conflicts with a requirement of IEC 60079-0, the requirement of this part of IEC 60079 takes precedence. This fifth edition cancels and replaces the fourth edition, published in 2010, and constitutes a technical revision. Refer to the Forward of the document for a complete listing of the technical changes between edition 5.0 and the previous edition of the document. Keywords: Group II electrical equipment with type of protection “n”

IEC 62990-2:2021 gives guidance on the selection, installation, use and maintenance of electrical equipment used for the measurement of toxic gases and vapours in workplace atmospheres. The primary purpose of such equipment is to ensure safety of personnel and property by providing an indication of the concentration of a toxic gas or vapour and warning of its presence. This document is applicable to equipment whose purpose is to provide an indication, alarm or other output function to give a warning of the presence of a toxic gas or vapour in the atmosphere and in some cases to initiate automatic or manual protective actions. It is applicable to equipment in which the sensor automatically generates an electrical signal when gas is present. For the purposes of this document, equipment includes: a) fixed equipment; b) transportable equipment, and c) portable equipment. This document is intended to cover equipment defined within IEC 62990-1, but can provide useful information for equipment not covered by that document.

This part of IEC 60079, which is a technical specification, specifies requirements for the construction, marking, and documenting of apparatus, systems and installations for use with the 2-Wire Intrinsically Safe Ethernet concept (2-WISE). The physical layer specification for 2-wire Ethernet 10BASE-T1L is defined in IEEE 802.3cg 2-WISE is the 2-Wire Intrinsically Safe Ethernet concept for advance physical layer (APL), designed to simplify the examination process for components and cable Entity Parameters within APL segments. This is achieved by defining universal Entity Parameter limits for APL ports, according to location and type of hazardous atmosphere, and listing a concise set of rules for the segment setup. The requirements for construction and installation of 2-WISE apparatus and systems are included in IEC 60079-11, IEC 60079-14, and IEC 60079-25, except as modified by this technical specification. Parts of a 2-WISE apparatus may be protected by any Type of Protection listed in IEC 60079-0 appropriate to the EPL for the intended use. In these circumstances, the requirements of this technical specification apply only to intrinsically safe circuits of the apparatus.

NEW!IEC 60079-0:2017 is available as IEC 60079-0:2017 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 60079-0:2017 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). This seventh edition cancels and replaces the sixth edition, published in 2011. This edition constitutes a technical revision. Refer to the Forward of the document for a complete listing of the technical changes between edition 7.0 and the previous edition of the document. Keywords: Ex Equipment and Ex Components intended for use in explosive atmospheres

This European Standard specifies minimum requirements and tests for electrical apparatus for the detection and measurement of combustible gases, toxic gases or oxygen using software and/or digital technologies. This European Standard is applicable to fixed, transportable and portable apparatus intended for use in domestic premises as well as commercial and industrial applications. This European Standard does not apply to external sampling systems, or to apparatus of laboratory or scientific type, or to apparatus used only for process control purposes. This European Standard supplements the requirements of the European Standards for the detection and measurement of flammable gases and vapours (e.g. EN 60079 29 1, EN 60079-29-4, EN 50194 1, EN 50194 2), toxic gases (e.g. EN 45544 series, EN 50291 1, EN 50291 2) or oxygen (e.g. EN 50104). NOTE 1 These European Standards will be mentioned in this European Standard as "metrological standards". NOTE 2 The examples above show the state of the standardisation for gas detection apparatus at the time of publishing this European Standard. There may be other metrological standards for which this European Standard is also applicable. This European Standard is a product standard which is based on EN 61508 series. It covers part of the phase 10 "realisation" of the overall safety life cycle defined in EN 61508 1. Additional requirements are specified if compliance with safety integrity level 1 (SIL 1) according to EN 61508 series is claimed for fixed or transportable apparatus for low demand mode of operation. NOTE 3 Compliance with safety integrity level 1 (SIL 1) for portable apparatus is not considered because portable apparatus cannot make an automatic executive action. It is recommended to apply this European Standard for apparatus used for safety applications with SIL-requirement 1 instead of EN 50402. However, the technical requirements of EN 50271 and EN 50402 are the same for SIL 1. NOTE 4 For apparatus used for safety applications with SIL-requirements higher than 1 EN 50402 is applicable.

This part of IEC 60079, which is a Technical Specification, provides guidance for equipment for use in explosive atmospheres in environments which may include ambient temperatures below –20 °С, and additional adverse conditions, including maritime applications. The purpose of this document is to provide recommendations to be considered for the design, manufacture and use of equipment. It is intended that this document be used for equipment operating within the environmental range specified on the certificate for the equipment.

IEC 60079-10-1:2020 is concerned with the classification of areas where flammable gas or vapour hazards may arise and may then be used as a basis to support the proper design, construction, operation and maintenance of equipment for use in hazardous areas. It is intended to be applied where there may be an ignition hazard due to the presence of flammable gas or vapour, mixed with air, but it does not apply to: a) mines susceptible to firedamp; b) the processing and manufacture of explosives; c) catastrophic failures or rare malfunctions which are beyond the concept of normality dealt with in this standard; d) rooms used for medical purposes; e) domestic premises; f) where a hazard may arise due to the presence of combustible dusts or combustible flyings but the principles may be used in assessment of a hybrid mixture. Flammable mists may form or be present at the same time as flammable vapour. In such case the strict application of the details in this document may not be appropriate. Flammable mists may also form when liquids not considered to be a hazard due to the high flash point are released under pressure. In these cases the classifications and details given in this document do not apply. For the purpose of this document, an area is a three-dimensional region or space. Atmospheric conditions include variations above and below reference levels of 101,3 kPa (1 013 mbar) and 20 °C (293 K), provided that the variations have a negligible effect on the explosion properties of the flammable substances. In any site, irrespective of size, there may be numerous sources of ignition apart from those associated with equipment. Appropriate precautions will be necessary to ensure safety in this context. This standard is applicable with judgement for other ignition sources but in some applications other safeguards may also need to be considered. E.g. larger distances may apply for naked flames when considering hot work permits. This document does not take into account the consequences of ignition of an explosive atmosphere except where a zone is so small that if ignition did occur it would have negligible consequences. This third edition of IEC 60079-10-1 cancels and replaces the second edition, published in 2015, and constitutes a technical revision, see foreword for further details.

IEC - adopted // Corrigenda

IEC 60079-13:2017(E) gives requirements for the design, construction, assessment, verification and marking of rooms used to protect internal equipment by pressurization or artificial ventilation or both as applicable when located in an explosive gas atmosphere or combustible dust atmosphere hazardous area with or without an internal source of a flammable gas or vapour. It also includes a room located in a non-hazardous area that has an internal source of release of a flammable gas or vapour. This document deals with rooms that are partially constructed in a manufacturer’s facility and intended to have the final installation completed on-site, as well as rooms that are constructed completely on-site. Rooms partially constructed in a manufacturer’s facility may include third-party verification. For rooms built on-site, this document can be used by plant operators as a guide for assessment of those facilities. This document represents a major technical revision of the requirements for equipment protection by pressurized room "p" and artificially ventilated room "v" and should be considered as introducing all new requirements. This second edition cancels and replaces the first edition published in 2010. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: - modification of the title of this document to include artificially ventilated room "v" in addition to pressurized room "p"; - addition of types of protection "pb", "pc", and "vc" and removal of types of protection "px", "py", "pz" and "pv"; - definition of the differences between pressurization and artificial ventilation types of protection; - removal of protection of rooms with an inert gas or a flammable gas from the scope of this document; - addition of an informative annex to include examples of applications where types of protection pressurization or artificial ventilation or pressurization and artificial ventilation can be used and associated guidelines. Additional information regarding the scope of this document can be found in Clause 1.

2017-05-29 - Annex ZZ available - Ensure it is issued with //FDIS

This part of IEC 60079 provides guidance for the application of electrical resistance trace heating systems in areas where explosive atmospheres may be present, with the exclusion of those classified as requiring EPL Ga/Da (traditional relationship to Zone 0 and Zone 20 respectively). It provides recommendations for the design, installation, maintenance and repair of trace heating systems including associated control and monitoring equipment. It does not cover devices that operate by induction heating, skin effect heating or direct pipeline heating, nor those intended for stress relieving.

This part of IEC 60079 specifies general and testing requirements for electrical resistance trace heaters for application in explosive gas atmospheres. The standard covers trace heaters that may comprise either factory- or field- (work-site) assembled units, and which may be series heating cables, parallel heating cables or heating pads and heating panels that have been assembled and/or terminated in accordance with the manufacturers instructions. This standard also includes requirements for termination assemblies and control methods used with trace heating. The hazardous areas referred to by this standard are those defined in IEC 60079-10.Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of this standard shall take precedence.

2021-03-25 CV: rejected for OJEU citation but corrigenda are out of EY scope
TAN - // IEC Corrigendum

This European Standard is applicable to apparatus and systems for the detection and measurement of flammable or toxic gases or vapours or oxygen. This European Standard is a product standard which is based on EN 61508 (all parts) and for gas detection systems covers both low and high demand mode at SIL capabilities of 1, 2 or 3 only. Gas detection apparatus and gas detection systems are developed as generic products. This standard covers part of the phase 10 “realisation” of the overall safety lifecycle defined in Figure 2 of EN 61508-1:2010. Configuration and integration into specific applications is not covered by this standard. In the event of conflict between the requirements of this standard and those of EN 61508, EN 50402 will take precedence. NOTE 1 Applications requiring a SIL capability of 4 for a gas detection system are not practicable. NOTE 2 This European Standard is dedicated mainly to fixed apparatus. For portable gas detectors claiming a SIL higher than 1, this European Standard may be applied. This European Standard supplements the requirements of the European Standards for electrical apparatus for the detection and measurement of flammable gases, vapours (e.g. EN 60079-29-1 or EN 60079-29-4), toxic gases (e.g. EN 45544) or oxygen (e.g. EN 50104). NOTE 3 These European Standards are called in the text "metrological standards". The examples above show the state of the standardisation for industrial applications at the time of publishing this European Standard. There may be other metrological standards covering other application fields, for which this European Standard is also applicable. EN 50271 specifies minimum requirements for apparatus using software and/or digital components. It also defines additional optional requirements for compliance with SIL 1 in low demand mode operation. EN 50402 includes all requirements of EN 50271. EN 50402 is also dedicated to apparatus and gas detection systems and/or components and should be used instead of EN 50271 in the following cases: - At SIL 1 when the system contains components not covered by EN 50271; - At SIL 2 and SIL 3; - At all SILs when non-digital based apparatus is used. Applying the above-mentioned metrological standards will ensure the measuring performance is adequate in normal operation of a gas detection system. Additionally the requirements of this European Standard address the functional safety of gas detection systems and encompass criteria for reliability, fault tolerance and avoidance of systematic failures. The avoidance and control of systematic failures will be covered by the requirements for the development processes and techniques and diagnostic measures chosen in the design. This European Standard will lead to the characterisation of the gas detection system by a SIL-capability and related hardware failure rate representing a hierarchical order of safety levels. This will allow the user to incorporate the gas detection system into an overall safety system according to the safety integrity levels of EN 61508 (all parts). This European Standard is applicable for gas detection systems, which may consist of the following functional units: - gas-sampling; - sensor; - signal transmission; - input to control unit; - signal processing in control unit; - output from control unit. This European Standard does not specify requirements for the installation and maintenance of gas detection systems. It also does not specify the physical positioning of measuring points / locations. This European Standard does not specify which SIL-capability is sufficient for which application. NOTE 4 The SIL-capability required for an application will be specified by the user (see Clause 9 and Annex A ).

IEC 60079-29-1:2016(E) specifies general requirements for construction, testing and performance, and describes the test methods that apply to portable, transportable and fixed equipment for the detection and measurement of flammable gas or vapour concentrations with air. The equipment, or parts thereof, is intended for use in explosive atmospheres and in mines susceptible to firedamp. This second edition of IEC 60079-29-1 cancels and replaces the first edition of IEC 60079-29-1:2007 series and constitutes a technical revision. Refer to the Forward of the document for a listing of the extensive changes between this edition and the previous edition. Keywords: detection and measurement of flammable gas or vapour concentrations with air, explosive atmospheres, mines susceptible to firedamp, explosion hazard

This Technical Specification specifies the construction, testing, installation and maintenance of Power i apparatus and systems which utilise electronically controlled spark duration limitation to maintain an adequate level of intrinsic safety. This Technical Specification contains requirements for intrinsically safe apparatus and wiring intended for use in explosive atmospheres and for associated apparatus intended for connection to intrinsically safe circuits entering such atmospheres. This Technical Specification excludes the level of protection “ia” and the use of software controlled circuits. This Technical Specification applies to electrical equipment utilising voltages not higher than 40 V d.c. and a safety factor 1,5 for Groups IIB, IIA, I and III. It is also applicable to Group IIC “ic” apparatus with a safety factor 1,0. Group IIC “ib” apparatus with a safety factor 1,5 are restricted to voltages up to 32 V d.c. This type of protection is applicable to electrical equipment in which the electrical circuits themselves are incapable of causing an explosion of the surrounding explosive atmospheres. This Technical Specification is applicable to intrinsically safe apparatus and systems which utilise electronically controlled spark duration limitation with the aim of providing more electrical power while maintaining an adequate level of safety. This Technical Specification is also applicable to electrical equipment or parts of electrical equipment located outside hazardous areas or protected by another type of protection listed in the IEC 60079 series, where the intrinsic safety of the electrical circuits in explosive atmospheres depends on the design and construction of such electrical equipment or parts of such electrical equipment. The electrical circuits located in the hazardous area are evaluated for use in such locations by applying his Technical Specification. This Technical Specification supplements and modifies the requirements of IEC 60079-0, IEC 60079-11, IEC 60079-14, IEC 60079-17 and IEC 60079-25.

IEC 62784:2017 covers electrical mobile motor-operated vacuum cleaners Equipment Protection Level (EPL) Dc. This includes dust extractors, for wet suction or dry suction, intended for commercial indoor use with or without attachments, to collect combustible dust in an explosive dust atmosphere. The requirements for the construction and testing covered by this document are applied in addition to the requirements for commercial and industrial vacuum cleaners in IEC 60335-2-69. This document supplements and modifies the requirements of IEC 60079-0. Whenever a requirement of this standard is in conflict with a requirement of IEC 60079-0 the requirement of this standard will take precedence. The following power systems are covered: - mains powered motors up to a rated voltage of 250 V for single-phase appliances and 480 V for other appliances. This document does not cover specific hazards associated with extreme ambient temperatures (less than –20 °C or higher than 40 °C) unless otherwise marked by the manufacturer as given in IEC 60079-0. The temperatures shall not exceed the temperature range of –20 °C to +60 °C. This document does not cover motorized cleaning heads for which additional requirements are under consideration. This document does not apply to: - back-pack vacuum cleaners; - vacuum cleaners with a traction drive; - vacuum cleaners and water-suction cleaning appliances for household use (IEC 60335-2-2); - floor treatment machines for commercial use (IEC 60335-2-67, IEC 60335-2-72); - spray extraction machines for commercial use (IEC 60335-2-68); - hand-held mains-operated electrical garden blowers, vacuums and blower vacuums (IEC 60335-2-100); - hand-held and transportable motor-operated electric tools (IEC 62841 series); - appliances for medical purposes (IEC 60601-1); - machines designed for use in corrosive environments; - machines designed for picking up flammable liquids; - machines designed for use in explosive environments due to the presence of explosive substances or pyrotechnical products, or unstable chemical substances.

IEC/TS 60079-32-1:2013(E) gives guidance about the equipment, product and process properties necessary to avoid ignition and electrostatic shock hazards arising from static electricity as well as the operational requirements needed to ensure safe use of the equipment, product or process. It can be used in a risk assessment of electrostatic hazards or for the preparation of product family or dedicated product standards for electrical or non-electrical machines or equipment. The purpose of this document is to provide standard recommendations for the control of static electricity, such as earthing of conductors, reduction of charging and restriction of chargeable areas of insulators. In some cases static electricity plays an integral part of a process, e.g. electrostatic coating, but often it is an unwelcome side effect and it is with the latter that this guidance is concerned. If the standard recommendations given in this document are fulfilled it can be expected that the risk of hazardous electrostatic discharges in an explosive atmosphere is at an acceptably low level. Keywords: risk assessment of electrostatic hazards, static electricity

IEC - Corrected version

IEC - Corrected version

IEC 60079-7:2015(E) specifies the requirements for the design, construction, testing and marking of electrical equipment and Ex Components with type of protection increased safety "e" intended for use in explosive gas atmospheres. Electrical equipment and Ex Components of type of protection increased safety "e" are either: - Level of Protection "eb" (EPL "Mb" or "Gb"); - or Level of Protection "ec" (EPL "Gc"). Level of Protection "eb" applies to equipment or Ex Components, including their connections, conductors, windings, lamps, and batteries; but not including semiconductors or electrolytic capacitors. Level of Protection "ec" applies to equipment or Ex Components, including their connections, conductors, windings, lamps, and batteries; and also including semiconductors and electrolytic capacitors. The requirements of this standard apply to both Levels of Protection unless otherwise stated. For Level of Protection "eb", this standard applies to electrical equipment where the rated voltage does not exceed 11 kV r.m.s., a.c. or d.c. For Level of Protection "ec", this standard applies to electrical equipment where the rated voltage does not exceed 15 kV r.m.s., a.c. or d.c. This standard supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of this standard takes precedence. This fifth edition cancels and replaces the fourth edition published in 2006, and constitutes a technical revision. Refer to the Foreword of the document for a complete listing of the technical changes between edition 5.0 and previous edition of the document. Keywords: electrical equipment and Ex Components with type of protection increased safety "e" intended for use in explosive gas atmospheres.

IEC 60079-28:2015 is available as IEC 60079-28:2015 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 60079-28:2015 specifies the requirements, testing and marking of equipment emitting optical radiation intended for use in explosive atmospheres. It also covers equipment located outside the explosive atmosphere or protected by a Type of Protection listed in IEC 60079-0, but which generates optical radiation that is intended to enter an explosive atmosphere. It covers Groups I, II and III, and EPLs Ga, Gb, Gc, Da, Db, Dc, Ma and Mb. This standard does not cover ignition by ultraviolet radiation and by absorption of the radiation in the explosive mixture itself. Explosive absorbers or absorbers that contain their own oxidizer as well as catalytic absorbers are also outside the scope of this standard. This second edition cancels and replaces the first edition, published in 2006, and constitutes a technical revision. Refer to the Foreword of the document for a complete listing of the technical changes between edition 2.0 and previous edition of the document. Keywords: equipment emitting optical radiation intended for use in explosive atmospheres

NEW! IEC 60079-29-2:2015 is available as IEC Standards+ 60079-29-2:2015 which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 60079-29-2:2015 gives guidance on, and recommended practice for, the selection, installation, safe use and maintenance of electrically operated Group II equipment intended for use in industrial and commercial safety applications and Group I equipment in underground coal mines for the detection and measurement of flammable gases complying with the requirements of IEC 60079-29-1 or IEC 60079-29-4. This second edition cancels and replaces the first edition published in 2007. This edition constitutes a technical revision. Please refer to the Foreword of the document for a listing of the changes from the previous edition. Keywords: gas detectors, flammable gases, vapours

1.1 This European Standard specifies requirements for automatic electrostatic flock application equipment which is designed for applying ignitable flock which may form explosive atmospheres in the flock application area. In this context a distinction is made between flock application devices which due to their type of construction comply with the requirements as laid down in EN 50050-3, as applicable, and those for which higher discharge energies are stipulated. This European Standard also specifies the constructional requirements for a safe operation of the stationary equipment of flock application booths, including the electrical installations and the accessories. This European Standard deals with all significant hazards, hazardous situations and events relevant to flock application booths, when they are used as intended and under conditions which are foreseeable as malfunction by the manufacturer (see Clause 4). 1.2 This European Standard considers three types of electrostatic flock systems. For more details, see Table 1. 1.3 This European Standard deals with those hazards occurring during stationary automatic electrostatic flocking. Among these hazards are, above all, ignition hazards of the generated explosive atmosphere and hazard to persons. 1.4 The stationary equipment dealt with in this European Standard is considered to be equipment of group II, category 3D for the use in areas with potential explosion hazards of zone 22. 1.5 This European Standard is not applicable for - flock systems in which mixtures of solvent vapours in air occur with a concentration of > 20 % of the LEL, - flock systems operated with AC voltage, - the application system for liquid or pasty substances (e.g. adhesives, primer), - the cleaning of flock application booths, - the storage and handling of ignitable substances outside the coating plant.

IEC 60079-32-2:2015 describes test methods concerning the equipment, product and process properties necessary to avoid ignition and electrostatic shock hazards arising from static electricity. It is intended for use in a risk assessment of electrostatic hazards or for the preparation of product family or dedicated product standards for electrical or non-electrical machines or equipment. The purpose of this part of IEC 60079 is to provide standard test methods used for the control of static electricity, such as surface resistance, earth leakage resistance, powder resistivity, liquid conductivity, capacitance and evaluation of the incendivity of provoked discharges. It is especially intended for use with existing standards of the IEC 60079 series. This part of IEC 60079 presents the latest state of knowledge which may, however, slightly differ from requirements in other standards, especially concerning test climates. When a requirement of this standard conflicts with a requirement specified in IEC 60079-0, to avoid the possibility of re-testing previously approved equipment, the requirement in IEC 60079-0 applies only for equipment within the scope of IEC 60079-0. In all other cases, the statements in this part of IEC 60079 apply. Keywords: ignition and electrostatic shock hazards, static electricity

IEC 60079-6:2015 specifies the requirements for the design, construction, testing and marking of Ex Equipment and Ex Components with type of protection liquid immersion "o" intended for use in explosive gas atmospheres. Ex Equipment and Ex Components of type of protection liquid immersion "o" are either: - Level of Protection "ob" (EPL "Mb" or "Gb") or - Level of Protection "oc" (EPL "Gc"). For Level of Protection "ob", this standard applies where the rated voltage does not exceed 11 kV r.m.s. a.c. or d.c. For Level of Protection "oc", this standard applies where the rated voltage does not exceed 15 kV r.m.s. a.c. or d.c. This standard supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of this standard takes precedence. This fourth edition cancels and replaces the third edition, published in 2007. This edition constitutes a technical revision. The significant changes with respect to the previous edition are: - Edition 4 represents a major technical revision of the requirements for oil immersion "o" and should be considered as introducing all new requirements. The normal "Table of Significant Changes" has not been included for this reason. In particular: - The requirements for oil immersion "o" have been redefined into liquid immersion, levels of protection "ob" and "oc" as recommended by the responses to 31/715/DC; - The ability to protect sparking contacts has been added to both "ob" and "oc". Additional requirements have been introduced for the protective liquid. Keywords: Ex Equipment and Ex Components with type of protection liquid immersion "o"

NEW! IEC 60079-5:2015 is available as IEC Standards+ 60079-5:2015 which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 60079-5:2015 contains specific requirements for the construction, testing and marking of electrical equipment, parts of electrical equipment and Ex components in the type of protection powder filling "q", intended for use in explosive gas atmospheres. This standard supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of this standard takes precedence. This standard applies to electrical equipment, parts of electrical equipment and Ex components with:
- a rated supply current less than or equal to 16 A; - a rated supply voltage less than or equal to 1 000 V; - a rated power consumption less than or equal to 1 000 W. This fourth edition cancels and replaces the third edition, published in 2007, and constitutes a technical revision. Refer to the Foreword of the document for a complete listing of the technical changes between edition 4.0 and previous edition of the document. Keywords: electrical equipment and Ex components in the type of protection powder filling "q"

NEW! IEC 60079-10-2:2015 is available as IEC Standards+ 60079-10-2:2015 which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 60079-10-2:201 5 is concerned with the identification and classification of areas where explosive dust atmospheres and combustible dust layers are present, in order to permit the proper assessment of ignition sources in such areas. In this standard, explosive dust atmospheres and combustible dust layers are treated separately. In Clause 4, area classification for explosive dusts clouds is described, with dust layers acting as one of the possible sources of release. In Clause 7 other general considerations for dust layers are described. The examples in this standard are based on a system of effective housekeeping being implemented in the plant to prevent dust layers from accumulating. Where effective housekeeping is not present, the area classification includes the possible formation of explosive dust clouds from dust layers. The principles of this standard can also be followed when combustible fibres or flyings might cause a hazard. This standard is intended to be applied where there can be a risk due to the presence of explosive dust atmospheres or combustible dust layers under normal atmospher ic conditions. Please refer to the foreword of the document for a detailed listing of the significant technical changes from the previous edition. Keywords: explosive dust atmospheres, combustible dust layers, ignition hazards

NEW! IEC 60079-18:2014 is available as IEC Standards+ 60079-18:2014 which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 60079-18:2014 gives the specific requirements for the construction, testing and marking of electrical equipment, parts of electrical equipment and Ex components with the type of protection encapsulation "m" intended for use in explosive gas atmospheres or explosive dust atmospheres. This part applies only for encapsulated electrical equipment, encapsulated parts of electrical equipment and encapsulat ed Ex components (hereinafter always referred to as "m" equipment) where the rated voltage does not exceed 11 kV. The application of electrical equipment in atmospheres, which may contain explosive gas as well as combustible dust simultaneously, may require additional protective measures. This standard does not apply to dusts of explosives, which do not require atmospheric oxygen for combustion, or to pyrophoric substances. This standard does not take account of any risk due to an emission of flammable or toxic gas from the dust. This standard supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requireme nt of this standard takes precedence. This International Standard is to be used in conjunction with IEC 60079-0, Explosive atmospheres - Part 0: Equipment-General requirements.This fourth edition cancels and replaces the third edition of IEC 60079-18:2009, and constitutes a technical revision. Please refer to the foreword of the document for a listing of the technical changes with respect to the previous edition. Keywords: encapsulation "m", explosive gas atmospheres, explosive dust atmospheres

NEW! IEC 60079-26:2014 is available as IEC Standards+ 60079-26:2014 which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 60079-26:2014 specifies alternative requirements for construction, test and marking for electrical equipment that provides Equipment Protection Level (EPL) Ga when single standardised Types of Protection (e.g. Ex "ia", Ex "ma", Ex "da") cannot be applied. This standard also applies to equipment mounted across a boundary where different Equipment Protection Levels may be required. This electrical equipment, within the operational parameters specified by the manufacturer, ensures a very high Level of Protection that includes rare malfunctions related to the equipment or two malfunctions occurring independently of each other. This standard supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of this standard takes precedence. This third edition cancels and replaces the second edition published in 2006 and constitutes a technical revision. The numerous changes are identified in the Foreword of the document. Keywords: Equipment Protection Level (EPL) Ga

This European Standard specifies requirements for the electromagnetic compatibility (EMC) for electrical apparatus for the detection and measurement of combustible gases, toxic gases or oxygen which are subject to the performance standards for gas detection apparatus, for example EN 45544 (all parts), EN 50104, EN 50194 (all parts), EN 50291, EN 50379 (all parts), EN 50543, EN 50545, EN 60079-29-1 or EN 60079-29-4. NOTE For the purpose of this standard the word ‘toxic’ covers ‘very toxic’, ‘toxic’, ‘harmful’, ‘corrosive‘, ‘irritating‘, ‘sensitising‘, ‘carcinogenic‘, ‘mutagenic‘ and ‘teratogenic‘. This European Standard applies to apparatus intended for use in residential, commercial and light-industrial environments as well as to apparatus intended for use in industrial environments. The apparatus may be AC-, DC- or battery powered. This European Standard is also applicable to apparatus which is intended for use in hazardous areas which may contain explosive or potentially explosive atmospheres. It covers only normal operation and does not cover safety requirements related to EMC phenomena. This standard is a product standard which is based on the product family standard EN 61326-1. This product standard takes precedence over the product family standard and over generic standards. This standard applies to electrical apparatus for the detection and measurement of combustible gases, toxic gases or oxygen that include functions specified by the manufacturer as being safety functions and can include functions specified as not being safety functions. All performance standards for the detection and measurement of combustible gases, toxic gases or oxygen include the minimum requirements for functional safety specified in EN 50271. There are also gas detectors and gas detection systems which are intended to be used with safety integrity levels SIL 1 to SIL 3 according to EN 50402 and EN 61508. For functional safety in industrial applications, this standard has taken into account those aspects of EN 61326–3–2 relating to the measuring and warning function of the apparatus defined as safety function. Apparatus of type 1 where the manufacturer claims a safety integrity level should be considered as type 2 apparatus with regard to immunity requirements. This standard specifies requirements for immunity tests in relation to continuous and transient, conducted and radiated disturbances, including electrostatic discharges, and also for emission tests. The test requirements are specified for each port considered. Apparatus falling within the scope of this European Standard is classified as follows by the following types. Type 1: apparatus intended for use in residential, commercial and light-industrial environments, as described in EN 61000-6-1 and EN 61000-6-3. Type 2: apparatus intended for use in industrial environments, as described in EN 61000-6-2 and EN 61000-6-4. This European Standard does not apply to any of the following: apparatus intended for the detection of dusts or mists in air; scientific or laboratory based apparatus used only for analysis or measurement; apparatus used exclusively for process measurement purposes; apparatus for medical purposes; apparatus used for breath alcohol measurement apparatus intended for the direct measurement of automotive exhaust gases.

NEW! IEC 60079-2:2014 is available as IEC Standards+ 60079-2:2014 which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 60079-2:2014 contains the specific requirements for the construction and testing of electrical equipment with pressurized enclosures, of type of protection "p", intended for use in explosi ve gas atmospheres or explosive dust atmospheres. It also includes the requirements for pressurized enclosures containing a limited release of a flammable substance. This standard supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requirements of this standard take precedence. This standard does not include the requirements for: - pressurized enclosures where the containment system may release air with an oxygen content greater than normal, or oxygen in combination with inert gas where the oxygen is in a proportion greater than 21 %; - pressurized rooms or analyser houses; see IEC 60079-13; - pressurized enclosures used where "explosives" or pyrotechnics are present; - pressurized enclosures used where hybrid mixtures of gas/vapour and combustible dust are present; - pressurized enclosures used where pyrophoric substances such as explosives or propellants containing their own oxidizers are present; - pressurized enclosures with an internal source of release of combustible dust. This sixth edition cancels and replaces the fifth edition published in 2007. This sixth edition cancels and replaces the first edition of IEC 61241-4 published in 2001. This sixth edition constitutes a technical revision. The significance of changes between IEC 60079-2, Edition 6.0, 2014 and IEC 60079-2, Edition 5.0, 2007 are as listed in the foreword of the document. Keywords: electrical equipment with pressurized enclosures, type of protection "p", explosive gas atmospheres, explosive dust atmospheres

IEC 60079-1: 2014 contains specific requirements for the construction and testing of electrical equipment with the type of protection flameproof enclosure "d", intended for use in explosive gas atmospheres. This standard supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of this standard will take precedence. This seventh edition cancels and replaces the sixth edition, published in 2007, and constitutes a technical revision. The numerous changes are identified in the Foreward of the document. Keywords: flameproof enclosure "d", explosive gas atmospheres

IEC 60079-29-3:2014 gives guidance for the design and implementation of a fixed gas detection system, including associated and/or peripheral gas detection equipment, for the detection of flammable gases/vapours and oxygen when used in a safety-related application in accordance with IEC 61508 and IEC 61511. This International standard also applies to the detection of toxic gases. Other parts of this international standard and pertinent local, national and international standards separately specify the performance requirements of a gas detector and a gas detection control unit (logic solver). These standards are commonly known as Metrological Performance Standards and are concerned with the accuracy of the measured value, the overall system performance, but not the device or system integrity with respect to the safety function. This international standard applies to the integrity of the safety function. Keywords: fixed gas detection system, flammable gases/vapours and Oxygen, detection of toxic gases

IEC 60079-14:2013 contains the specific requirements for the design, selection, erection and initial inspection of electrical installations in, or associated with, explosive atmospheres. Where the equipment is required to meet other environmental conditions, for example, protection against ingress of water and resistance to corrosion, additional protection requirements may be necessary. The requirements of this standard apply only to the use of equipment under standard atmospheric conditions as defined in IEC 60079-0. For other conditions, additional precautions may be necessary, and the equipment should be certified for these other conditions. For example, most flammable materials and many materials which are normally regarded as non-flammable might burn vigorously under conditions of oxygen enrichment. These requirements are in addition to the requirements for installations in non-hazardous areas. This standard applies to all electrical equipment including fixed, portable, transportable and personal, and installations, permanent or temporary. No account is taken in this Standard of the toxic risks that are associated with flammable gases, liquids and dusts in concentrations that are usually very much less than the lower explosive limit. In locations where personnel may be exposed to potentially toxic concentrations of flammable material, appropriate precautions should be taken. Such precautions are outside the scope of this Standard. This fifth edition cancels and replaces the fourth edition published in 2007. This edition constitutes a technical revision. Refer to the document's Foreward for a listing of the specific revisions and additional Notes. Key words: requirements for the design, selection, erection and initial inspection of electrical installations in explosive atmospheres

IEC 60079-31:2013 is applicable to electrical equipment protected by enclosure and surface temperature limitation for use in explosive dust atmospheres. It specifies requirements for design, construction and testing of electrical equipment and Ex Components. This standard supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of this standard takes precedence. This standard does not apply to dusts of explosives, which do not require atmospheric oxygen for combustion, or to pyrophoric substances. This standard does not apply to electrical equipment or Ex Components intended for use in underground parts of mines as well as those parts of surface installations of such mines endangered by firedamp and/or combustible dust. This standard does not take account of any risk due to an emission of flammable or toxic gas from the dust. Consideration of additional protective measures is required where the application of electrical equipment is in atmospheres, which can contain combustible dust as well as explosive gas, whether simultaneously or separately. Where the electrical equipment has to meet other environmental conditions, for example, protection against ingress of water and resistance to corrosion, additional measures can be necessary. The measures used should not adversely affect the integrity of the enclosure. This second edition cancels and replaces the first edition published in 2008. This edition constitutes a technical revision. The major technical changes include: - The marked maximum surface temperature shall be measured on the external surfaces of the enclosure and the surfaces of the internal components for equipment with types of protection 'ta'; - Additional protection for arcing and sparking parts for 'ta'; - Test for internal enclosure for level 'ta' added. Keywords: explosive dust atmospheres