SIST EN 60079-26:2015
(Main)Explosive atmospheres - Part 26: Equipment with equipment protection level (EPL) Ga (IEC 60079-26:2014)
Explosive atmospheres - Part 26: Equipment with equipment protection level (EPL) Ga (IEC 60079-26:2014)
This part of IEC 60079 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.
EXAMPLE: Equipment installed in the wall of a storage vessel containing Zone 0 (requiring EPL Ga) inside an
area defined as Zone 1 (requiring EPL Gb).
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.
NOTE A malfunction may result from a failure of the component parts of the electrical equipment or from
anticipated externally applied influences. Two independent malfunctions which may occur more frequently and
which, separately, would not create an ignition hazard but which, in combination, could create a potential ignition
hazard, are regarded as occurring together to form a rare malfunction.
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.
Explosionsgefährdete Bereiche - Teil 26: Betriebsmittel mit Geräteschutzniveau (EPL) Ga (IEC 60079-26:2014)
Atmosphères explosives - Partie 26: Matériel d'un niveau de protection du matériel (EPL) Ga (IEC 60079-26:2014)
Eksplozivne atmosfere - 26. del: Oprema s stopnjo zaščite opreme Ga (IEC 60079-26:2014)
Ta del standarda IEC 60079 določa nadomestne zahteve za izdelavo, preskušanje in označevanje električne opreme, ki zagotavlja stopnjo zaščite opreme (ELP) Ga, če ni mogoče uporabiti enotne standardizirane vrste zaščite (npr. Ex »ia« , Ex »ma«, Ex »da«). Ta standard velja tudi za opremo, nameščeno prek meje, kjer sta lahko zahtevani dve različni stopnji zaščite.
PRIMER: Oprema, nameščena v steni posode za shranjevanje, ki vsebuje cono 0, (zahtevan ELP Ga) v območju, ki je določeno kot cona 1 (zahtevan ELP Gb).
Ta električna oprema zagotavlja, v okviru parametrov delovanja, ki jih je določil proizvajalec, zelo visoko stopnjo zaščite, ki zajema redke okvare, povezane z opremo, ali dve okvari, ki se pojavita neodvisno druga od druge.
OPOMBA Okvara je lahko posledica napake sestavnih delov električne opreme ali pričakovanih zunanjih vplivov. Dve neodvisni okvari, ki lahko nastaneta bolj pogosto in ki vsaka posebej ne bi povzročili nevarnosti vžiga, vendar pa bi obe skupaj lahko povzročili morebitno nevarnost vžiga, se obravnavata, kot da sta se pripetili hkrati in povzročili redko okvaro.
Ta standard dopolnjuje in spreminja splošne zahteve standarda IEC 60079-0. Kadar je zahteva iz tega standarda v nasprotju z zahtevo iz standarda IEC 60079-0, ima prednost zahteva iz tega standarda.
General Information
Relations
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Explosionsgefährdete Bereiche - Teil 26: Betriebsmittel mit Geräteschutzniveau (EPL) Ga (IEC 60079-26:2014)Atmosphères explosives - Partie 26: Matériel d'un niveau de protection du matériel (EPL) Ga (IEC 60079-26:2014)Explosive atmospheres - Part 26: Equipment with equipment protection level (EPL) Ga (IEC 60079-26:2014)29.260.20Electrical apparatus for explosive atmospheresICS:Ta slovenski standard je istoveten z:EN 60079-26:2015SIST EN 60079-26:2015en01-april-2015SIST EN 60079-26:2015SLOVENSKI
STANDARDSIST EN 60079-26:20071DGRPHãþD
SIST EN 60079-26:2015
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 60079-26
January 2015 ICS 29.260.20
Supersedes
EN 60079-26:2007
English Version
Explosive atmospheres -
Part 26: Equipment with Equipment Protection Level (EPL) Ga (IEC 60079-26:2014)
Atmosphères explosives -
Partie 26: Matériel d'un niveau de protection du matériel (EPL) Ga (IEC 60079-26:2014)
Explosionsgefährdete Bereiche -
Teil 26: Betriebsmittel mit Geräteschutzniveau (EPL) Ga (IEC 60079-26:2014) This European Standard was approved by CENELEC on 2014-12-02. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung CEN-CENELEC Management Centre: Avenue Marnix 17,
B-1000 Brussels © 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 60079-26:2015 E SIST EN 60079-26:2015
EN 60079-26:2015 - 2 - Foreword The text of document 31/1146/FDIS, future edition 3 of IEC 60079-26, prepared by IEC/TC 31 "Equipment for explosive atmospheres" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 60079-26:2015.
The following dates are fixed: • latest date by which the document has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2015-09-02 • latest date by which the national standards conflicting with the document have to be withdrawn (dow) 2017-12-02
This document supersedes EN 60079-26:2007.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a mandate given to CENELEC by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s).
For the relationship with EU Directive(s) see informative Annex ZZ, which is an integral part of this document.
Endorsement notice The text of the International Standard IEC 60079-26:2014 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 60079-7 NOTE Harmonized as EN 60079-7. IEC 60079-14 NOTE Harmonized as EN 60079-14. IEC 60079-18 NOTE Harmonized as EN 60079-18. SIST EN 60079-26:2015
- 3 - EN 60079-26:2015 Annex ZA (normative)
Normative references to international publications with their corresponding European publications
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here: www.cenelec.eu
Publication Year Title EN/HD Year
IEC 60079-0 -
Explosive atmospheres -
Part 0: Equipment - General requirements - -
IEC 60079-1 -
Explosive atmospheres -
Part 1: Equipment protection
by flameproof enclosures "d" EN 60079-1 -
IEC 60079-11 -
Explosive atmospheres -
Part 11: Equipment protection by intrinsic safety "i" EN 60079-11 -
IEC 60529 -
Degrees of protection provided by enclosures (IP Code) EN 60529 -
IEC 60695-11-10 -
Fire hazard testing -
Part 11-10: Test flames - 50 W horizontal and vertical flame test methods EN 60695-11-10 -
SIST EN 60079-26:2015
EN 60079-26:2015 - 4 - Annex ZZ (informative)
Coverage of Essential Requirements of EU Directives
This European Standard has been prepared under a mandate given to CENELEC by the European Commission and the European Free Trade Association and within its scope the standard covers only the following essential requirements out of those given in Annex II of the EU Directive 94/9/EC:
– ER 1.0.1 (partly), 1.0.2 (partly), ER 1.0.3 to ER 1.0.6 – ER 1.1.1, ER 1.1.2 – ER 1.2.1, ER 1.2.3, ER 1.2.5 (partly), ER 1.2.8, ER 1.2.9 – ER 1.3.1 (partly), ER 1.3.3, ER 1.3.4 – ER 1.4.1, ER 1.4.2 – ER 2.1.1 – ER 2.1.1.1, ER 2.1.1.2 (partly)
Compliance with this standard provides one means of conformity with the specified essential requirements of the Directive[s] concerned.
WARNING: Other requirements and other EU Directives may be applicable to the products falling within the scope of this standard. SIST EN 60079-26:2015
- 5 - EN 60079-26:2015 Annex ZY (informative)
Significant changes between this European Standard and EN 60079-26:2007 This European Standard supersedes EN 60079-26:2007. The significant changes with respect to EN 60079-26:2007 are as listed below.
Type Changes Clause Minor and editorial changes Extension Major technical changes Notes deleted 1 X
Reference to associated apparatus deleted 1 X
Additional normative references included 3 X
Requirements against
mechanical and electrostatic ignition hazards deleted (now covered in EN 60079-0)
4.1 X
Requirement for separation element detailed regarding external influences 4.1.3.2 X
Intrinsic safety Ex ia as single type of protection including associated apparatus deleted (now covered by EPL) 4.2.2 (ed.2) X
Encapsulation Ex ma as single type of protection deleted (now covered by EPL) 4.2.3 (ed.2) X
Conditions a) and b) linked with an “and”, therefore requirement of “flameproof joint” deleted in following clause. Both requirements already covered by separation elements and standardised process connections. 4.3 X
Process connection requires a sufficiently tight joint: IP66 added alternatively to IP67 4.3
X
Requirement for isolated conductive components deleted (now covered in EN 60079-0) 4.4 (ed.2) X
Requirements for non-conductive enclosures deleted (now covered in EN 60079-0) 4.5 (ed.2) X
Test of partition walls according to 4.1.3.2 b) is specified in more detail 5.2
C1 Marking example for associated apparatus deleted 6.2 b) X
Note 3 with an additional example added 6.2 X
Specification of material of partition wall required in instructions (also required in 4.1.3.2) 7 X
Alternative risk assessment method deleted (is now generally introduced) Annex A (ed.2) X
NOTE
The technical changes referred to include the significance of technical changes in the revised EN standard, but they do not form an exhaustive list of all modifications from the previous version. More guidance may be found by referring to the Redline Version of the standard. SIST EN 60079-26:2015
EN 60079-26:2015 - 6 - Explanations: A) Definitions 1) Minor and editorial changes: - clarification - decrease of technical requirements - minor technical change - editorial corrections
These are changes which modify requirements in an editorial or a minor technical way. They include changes
of the wording to clarify technical requirements without any technical change, or a reduction in level of existing requirement.
2) Extension: Addition of technical options
These are changes which add new or modify existing technical requirements, in a way that new options are given, but without increasing requirements for equipment that was fully compliant with the previous standard. Therefore, these will not have to be considered for products in conformity with the preceding edition.
3) Major technical change:
- addition of technical requirements - increase of technical requirements
These are changes to technical requirements (addition, increase of the level or removal) made in a way that a product in conformity with the preceding edition will not always be able to fulfil the requirements given in the later edition. These changes have to be considered for products in conformity with the preceding edition. For these changes additional information is provided in Clause B) below.
NOTE: These changes represent current technological knowledge. However, these changes should not normally have an influence on equipment already placed on the market.
B) Information about the background of ‘Major Technical Changes’ C1 –
Introduction of type tests for separation elements according to “4.1.3.2 b)” SIST EN 60079-26:2015
IEC 60079-26 Edition 3.0 2014-10 INTERNATIONAL STANDARD NORME INTERNATIONALE Explosive atmospheres –
Part 26: Equipment with Equipment Protection Level (EPL) Ga
Atmosphères explosives – Partie 26: Matériel d'un niveau de protection du matériel (EPL) Ga
INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE Q ICS 29.260.20 PRICE CODE CODE PRIX ISBN 978-2-8322-1903-4
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale ®
Warning! Make sure that you obtained this publication from an authorized distributor.
Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé. SIST EN 60079-26:2015
– 2 – IEC 60079-26:2014 © IEC 2014
CONTENTS
FOREWORD . 3 1 Scope . 6 2 Normative references. 6 3 Terms and definitions . 7 4 Requirements for design and construction . 7 4.1 Protection measures against ignition hazards of the electrical circuits . 7
General . 7 4.1.1 Application of two independent Types of Protection providing EPL Gb . 7 4.1.2 Application of a Type of Protection providing EPL Gb and a separation 4.1.3element . 8 4.2 Equipment with moving parts . 12
Frictional heating . 12 4.2.1 Damage arising from failure of moving parts . 12 4.2.2 Light metals . 12 4.2.34.3 Process connection . 13 5 Type tests . 13 5.1 Standardized types of protection . 13 5.2 Separation elements . 13 5.3 Temperature evaluation . 13 6 Marking . 14 6.1 General . 14 6.2 Examples of marking . 14 7 Instructions. 14 7.1 Separation elements: . 14 7.2 Process connection: . 15 7.3 EPL allocation . 15 Bibliography . 16
Figure 1 – Example of a partition wall with a conductor bushing
considered as gas diffusion tight . 9 Figure 2 – Example of a separation element
with a cylindrical shaft joint and naturalventilation . 12
Table 1 – Separation elements . 11
SIST EN 60079-26:2015
IEC 60079-26:2014 © IEC 2014 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION ____________
EXPLOSIVE ATMOSPHERES –
Part 26: Equipment with Equipment Protection Level
(EPL) Ga
FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by independent certification bodies. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 60079-26 has been prepared by IEC technical committee 31: Equipment for explosive atmospheres. This third edition cancels and replaces the second edition published in 2006 and constitutes a technical revision.
SIST EN 60079-26:2015
– 4 – IEC 60079-26:2014 © IEC 2014
This edition includes the following significant changes with respect to the previous edition:
Type Changes Clause Minor and editorial changes Extension Major technical changes Notes deleted 1 X
Reference to associated apparatus deleted 1 X
Additional normative references included 3 X
Requirements against
mechanical and electrostatic ignition hazards deleted (now covered in IEC 60079-0)
4.1 X
Requirement for separation element detailed regarding external influences 4.1.3.2 X
Intrinsic safety Ex ia as single type of protection including associated apparatus deleted (now covered by EPL) 4.2.2 (ed.2) X
Encapsulation Ex ma as single type of protection deleted (now covered by EPL) 4.2.3 (ed.2) X
Conditions a) and b) linked with an “and” , therefore requirement of “flameproof joint” deleted in following clause. Both requirements already covered by separation elements and standardised process connections. 4.3 X
Process connection requires a sufficiently tight joint: IP66 added alternatively to IP67 4.3
X
Requirement for isolated conductive components deleted (now covered in IEC 60079-0) 4.4 (ed.2) X
Requirements for non-conductive enclosures deleted (now covered in IEC 60079-0) 4.5 (ed.2) X
Test of partition walls according to 4.1.3.2 b) is specified in more detail 5.2
C1 Marking example for associated apparatus deleted 6.2 b) X
Note 3 with an additional example added 6.2 X
Specification of material of partition wall required in instructions (also required in 4.1.3.2) 7 X
Alternative risk assessment method deleted (is now generally introduced) AnnexA (ed.2) X
NOTE The technical changes referred to include the significance of technical changes in the revised IEC Standard, but they do not form an exhaustive list of all modifications from the previous version. Explanation of the types of changes: A) Definitions 1) Minor and editorial changes: • Clarification • Decrease of technical requirements • Minor technical change • Editorial corrections These are changes which modify requirements in an editorial or a minor technical way. They include changes of the wording to clarify technical requirements without any technical change, or a reduction in level of existing requirement. SIST EN 60079-26:2015
IEC 60079-26:2014 © IEC 2014 – 5 –
2) Extension: Addition of technical options These are changes which add new or modify existing technical requirements, in a way that new options are given, but without increasing requirements for equipment that was fully compliant with the previous standard.Therefore, these will not have to be considered for products in conformity with the preceding edition. 3) Major technical changes: • addition of technical requirements • increase of technical requirements These are changes to technical requirements (addition, increase of the level or removal) made in a way that a product in conformity with the preceding edition will not always be able to fulfil the requirements given in the later edition. These changes have to be considered for products in conformity with the preceding edition. For these changes additional information is provided in Clause B below. NOTE These changes represent current technological knowledge. However, these changes should not normally have an influence on equipment already placed on the market. B) Information about the background of ‘Major technical changes’ C1: Introduction of type tests for separation elements according to “4.1.3.2 b)” The text of this standard is based on the following documents: FDIS Report on voting 31/1146/FDIS 31/1155/RVD
Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. A list of all parts in the IEC 60079 series, published under the general title Explosive atmospheres, can be found on the IEC website. The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to the specific publication. At this date, the publication will be
• reconfirmed, • withdrawn, • replaced by a revised edition, or • amended.
SIST EN 60079-26:2015
– 6 – IEC 60079-26:2014 © IEC 2014
EXPLOSIVE ATMOSPHERES –
Part 26: Equipment with Equipment Protection Level
(EPL) Ga
1 Scope This part of IEC 60079 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. EXAMPLE: Equipment installed in the wall of a storage vessel containing Zone 0 (requiring EPL Ga) inside an area defined as Zone 1 (requiring EPL Gb). 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. NOTE A malfunction may result from a failure of the component parts of the electrical equipment or from anticipated externally applied influences. Two independent malfunctions which may occur more frequently and which, separately, would not create an ignition hazard but which, in combination, could create a potential ignition hazard, are regarded as occurring together to form a rare malfunction. 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. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60079-0, Explosive atmospheres − Part 0: Equipment − General requirements IEC 60079-1, Explosive atmospheres − Part 1: Equipment protection by flameproof enclosures "d" IEC 60079-11, Explosive atmospheres − Part 11: Equipment protection by intrinsic safety "i" IEC 60695-11-10, Fire hazard testing − Part 11-10: Test flames − 50 W horizontal and vertical flame test methods IEC 60529, Degrees of protection provided by enclosures (IP Code) SIST EN 60079-26:2015
IEC 60079-26:2014 © IEC 2014 – 7 –
3 Terms and definitions For the purposes of this document, the terms and definitions given in IEC 60079-0 and the following apply.
NOTE Additional definitions applicable to explosive atmospheres can be found in IEC 60050-426. 3.1
separation element mechanical element inside the equipment, which separates different parts of the equipment with different EPLs Note 1 to entry: A separation element consists of a mechanical partition wall, which may be combined with a flameproof joint or a natural ventilation 4 Requirements for design and construction 4.1 Protection measures against ignition hazards of the electrical circuits
General 4.1.1The equipment shall comply with the requirements of 4.1.2 or 4.1.3 in the event of a failure of one equipment means of protection, by the provision of a second independent means of protection. NOTE 1 Types of Protection according to EPL Ga do not require a second independant means of protection, e.g. Ex “ia” (IEC 60079-11), Ex “ma” (IEC 60079-18), Ex “da” (IEC 60079-1). Electrical connections and permanently connected cables of the equipment sited within an area requiring EPL Ga equipment shall comply with the same Level of Protection required by this standard, for example a cable suitable for EPL Gb containing non-Ex “ia” circuits additionally protected by a flameproof conduit or a cable suitable for EPL Gb provided with earth leakage protection. NOTE 2 Detailed cable and installation requirements for Types of Protection accepted as achieving EPL Ga beyond intrinsically safe circuits are under consideration in IEC 60079-14.
NOTE 3 Because of ignition hazards which can arise from faults and/or transient circulating currents in the potential equalization system, galvanic isolation in the power and signal connections to the equipment according to 4.1.2 and 4.1.3 is commonly applied along with minimizing the effect of transient fault currents in the potential equalization network by the use of electrical protection equipment such as sensitive earth leakage monitors.
Application of two independent Types of Protection providing EPL Gb 4.1.2Electrical equipment shall comply with the requirements of two independent Types of Protection that provide EPL Gb. If one Type of Protection fails, the other Type of Protection shall continue to function. The independent Types of Protection shall not have a common mode of failure, except as specified in this clause. Combined types of protection providing EPL Gb shall depend on different physical protection principles.
NOTE 1 An example of a common mode of failure is if an Ex “d” enclosure containing arcing components is installed
inside an Ex “e” enclosure. Should
the Ex “d” enclosure be compromised, it would also compromise the Ex “e” enclosure.
NOTE 2 The combination of Ex “d” and Ex “q” both depend on the avoidance of flame propagation (same physical protection principle) and may not be useful in combination. In practice, some combinations may not be useful, for example the combination of oil immersion “o” and powder filling “q”. Where combined types of protection are used, it shall be possible for each Type of Protection to be tested individually (see 5.1). Both Types of Protection shall be assessed using the most arduous fault condition of the other Type of Protection. When combining intrinsic safety, Type of Protection “ib”, with other SIST EN 60079-26:2015
– 8 – IEC 60079-26:2014 © IEC 2014
Types of Protection, the second Type of Protection shall be assessed, with the most arduous fault condition applied to the intrinsically safe circuit. Thermal dissipation shall be considered in case of a fault of one Type of protection. When using two Types of Protection, which both rely on the same parameter (for example, the creepage distance combining Ex “ib” with Ex “e”), the most stringent requirement of both Types of Protection shall be applied. If two Types of Protection are combined which both rely on the enclosure, one of the following shall be met: a) if two enclosures are used (one totally enclosed within the other), each enclosure shall comply with the requirements of the respective Type of Protection; or b) if only one enclosure is used, the enclosure and the cable glands shall meet the impact test requirements of IEC 60079-0, using the Group I values. Examples of relevant combinations of two independent Types of Protection are as follows: – inductive transmitters (for example proximity switches, electrical position sensors) with intrinsic safety “ib” enclosed by encapsulation “mb”. The connections to intrinsically safe “ib” circuits can be protected by the increased safety “e”; – a luminaire designed as increased safety “e”may be included in a flameproof enclosure “d”: – measuring transducers with intrinsic safety “ib” and a flameproof enclosure “d”; – equipment with electrical circuits of intrinsic safety “ib”, additionally protected by powder filling “q”; – electromagnetic valves with encapsulation “mb”, enclosed by a flameproof enclosure “d”; – increased safety “e”, with pressurized equipment “pxb”.
Application of a Type of Protection pro
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