EN 60079-1:2014

Explosive atmospheres - Part 1: Equipment protection by flameproof enclosures "d"

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

Explosionsgefährdete Bereiche - Teil 1: Geräteschutz durch druckfeste Kapselung „d“

Atmosphères explosives - Partie 1: Protection du matériel par enveloppes antidéflagrantes «d»

IEC 60079-1: 2014 contient les exigences spécifiques de construction et d'essai du matériel électrique à enveloppe antidéflagrante, mode de protection "d", destiné à être utilisé dans les atmosphères explosives gazeuses. La présente Norme complète et modifie les exigences générales de l'IEC 60079-0. Lorsqu'une exigence de cette norme entre en conflit avec une exigence de l'IEC 60079-0, l'exigence de la présente norme prévaudra. Cette septième édition annule et remplace la sixième édition parue en 2007. Cette édition constitue une révision technique. Les nombreux changements sont identifiés dans l'avant-propos du document. Mots clés : enveloppe antidéflagrante "d", atmosphères explosives IEC 60079-1: 2014 contient les exigences spécifiques de construction et d'essai du matériel électrique à enveloppe antidéflagrante, mode de protection "d", destiné à être utilisé dans les atmosphères explosives gazeuses. La présente Norme complète et modifie les exigences générales de l'IEC 60079-0. Lorsqu'une exigence de cette norme entre en conflit avec une exigence de l'IEC 60079-0, l'exigence de la présente norme prévaudra. Cette septième édition annule et remplace la sixième édition parue en 2007. Cette édition constitue une révision technique. Les nombreux changements sont identifiés dans l'avant-propos du document. Mots clés : enveloppe antidéflagrante "d", atmosphères explosives gazeuses

Eksplozivne atmosfere - 1. del: Zaščita opreme z neprodirnim okrovom "d"

Ta del standarda IEC 60079 vsebuje specifične zahteve za konstrukcijo in preskušanje zaščite električne opreme z neprodirnim okrovom "d", ki je namenjena za uporabo v eksplozivnih plinskih atmosferah.
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

• Status: Published
• Publication Date: 09-Oct-2014
• Withdrawal Date: 31-Jul-2017
• ICS: 29.260.20 - Electrical apparatus for explosive atmospheres
• Technical Committee: CLC/TC 31 - Electrical apparatus for explosive atmospheres - General requirements
• Drafting Committee: CLC/SC 31-2 - Flameproof enclosures “d”
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 10-Oct-2014
• Completion Date: 10-Oct-2014
• Directive: 2008/68/EC - Directve 2008/68/EC of the European Parliament and of the council of 24 September 2008 on the inland transport of the dangerous goods
• Directive: 2014/34/EU - Directive 2014/34/EU Of The European Parliament And Of The Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to equipment and protective systems intended for use in potentially explosive atmospheres (recast)
• Directive: 94/9/EC - Directive 94/9/EC of the European Parliament and the Council of 23 March 1994 on the approximation of the laws of the Member States concerning equipment and protective systems intended for use in potentially explosive atmospheres
• Ref Project: SIST EN 60079-1:2015 - Explosive atmospheres - Part 1: Equipment protection by flameproof enclosures "d"

Relations

• Replaces: EN 60079-1:2007 - Explosive atmospheres - Part 1: Equipment protection by flameproof enclosures "d"
• Effective Date: 28-Jan-2023
• Amended By: EN 60079-1:2014/A11:2024 - Explosive atmospheres - Part 1: Equipment protection by flameproof enclosures "d"
• Effective Date: 01-Mar-2022
• Corrected By: EN 60079-1:2014/AC:2018-09 - Explosive atmospheres - Part 1: Equipment protection by flameproof enclosures "d"
• Effective Date: 23-Jan-2023

Overview

EN 60079-1:2014 (IEC 60079-1:2014) specifies construction and test requirements for electrical equipment protected by flameproof enclosure “d” for use in explosive gas atmospheres. It supplements and modifies the general requirements of IEC 60079-0 and takes precedence where conflicts occur. This seventh edition supersedes EN 60079-1:2007 and provides a technical revision with updated test methods, joint requirements and documentation/marking expectations. The standard is harmonized for use within EU regulatory frameworks and supports conformity with relevant essential requirements.

Key topics and technical requirements

• Scope and relationship to IEC 60079-0 - supplements general requirements; precedence declared where conflicts exist.
• Flameproof joints - detailed requirements for threaded, non‑threaded, serrated and multi‑step joints; examples and documentation expectations; limits on repair and corrosion protection.
• Threaded and non‑threaded entries - metric and NPT thread considerations, reduced-length threaded joints and associated verification.
• Cemented, fused glass and other joints - construction, leakage evaluation and mechanical securement requirements.
• Fasteners, openings and blanking elements - material, torque and design guidance; documentation to support installation and maintenance.
• Breathing and draining devices - thermal tests, pressure resistance and external surface temperature classification after test periods.
• Type and routine tests - overpressure (static/dynamic), non‑transmission of internal ignition, sequence/number of samples and test adaptations for small or low‑ambient equipment.
• Materials and special atmospheres - limitations for copper/copper alloys in acetylene atmospheres and other material-related constraints.
• Non‑metallic enclosures - construction, tracking/creepage requirements and type test sequences.
• Batteries and internal sources - acceptable cell types, charging/recharging considerations and prevention of excessive temperatures.
• Marking, documentation and Ex component requirements - certificate and marking content for Ex components and enclosures.
• New normative annexes - including alternative risk assessment methods for protection levels and requirements for enclosures with internal release sources or machine applications.

Practical applications and users

This standard is essential for:

• Manufacturers and designers of flameproof electrical equipment and luminaires for hazardous locations
• Certification and testing laboratories performing type and routine tests for Ex “d” equipment
• Installation, maintenance and safety engineers responsible for selecting and servicing equipment in explosive gas atmospheres
• Regulatory and compliance teams preparing technical documentation and conformity evidence for EU directives

Adoption ensures equipment is designed, tested and documented to withstand internal explosions without transmitting flames to the external explosive atmosphere, reducing ignition risks and enabling safe deployment in hazardous areas.

Related standards

• IEC / EN 60079-0 (General requirements)
• IEC / EN 60079-7 (Increased safety “e”)
• IEC / EN 60079-11 (Intrinsic safety “i”)
• IEC / EN 60079-15 (Type of protection “n”)
  (References and normative cross‑references are listed in Annex ZA of the standard.)

Standards Content (Sample)

SLOVENSKI STANDARD
01-januar-2015
(NVSOR]LYQHDWPRVIHUHGHO=DãþLWDRSUHPH]QHSURGLUQLPRNURYRPG
Explosive atmospheres - Part 1: Equipment protection by flameproof enclosures "d"
Explosionsgefährdete Bereiche - Teil 1: Geräteschutz durch druckfeste Kapselung „d“
Atmosphères explosives - Partie 1: Protection de l'appareil par enveloppes
antidéflagrantes "d"
Ta slovenski standard je istoveten z: EN 60079-1:2014
ICS:
29.260.20 (OHNWULþQLDSDUDWL]D Electrical apparatus for
HNVSOR]LYQDR]UDþMD explosive atmospheres
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 60079-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2014
ICS 29.260.20 Supersedes EN 60079-1:2007
English Version
Explosive atmospheres - Part 1: Equipment protection by
flameproof enclosures "d"
(IEC 60079-1:2014)
Atmosphères explosives - Partie 1: Protection de l'appareil Explosionsgefährdete Bereiche - Teil 1: Geräteschutz
par enveloppes antidéflagrantes "d" durch druckfeste Kapselung "d"
(CEI 60079-1:2014) (IEC 60079-1:2014)
This European Standard was approved by CENELEC on 2014-08-01. 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
© 2014 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 60079-1:2014 E
Foreword
The text of document 31/1111/FDIS, future edition 7 of IEC 60079-1, prepared by IEC/TC 31 "Equipment for
explosive atmospheres" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
(dop) 2015-05-01
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2017-08-01
• latest date by which the national
standards conflicting with the
document have to be withdrawn
This document supersedes EN 60079-1:2007.

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.

For the relationship with EU Directive see informative Annex ZZ, which is an integral part of this document.

Endorsement notice
The text of the International Standard IEC 60079-1:2014 was approved by CENELEC as a European
Standard without any modification.

- 3 - EN 60079-1:2014
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 60061 -  Lamp caps and holders together with gauges - -
for the control of interchangeability and safety
IEC 60079-0 (mod) -  Explosive atmospheres - Part 0: Equipment - EN 60079-0 -
General requirements
+A11 2013
IEC 60079-7 -  Explosive atmospheres - Part 7: Equipment EN 60079-7 -
protection by increased safety "e"
IEC 60079-11 -  Explosive atmospheres - Part 11: Equipment EN 60079-11 -
protection by intrinsic safety "i"
IEC 60079-15 -  Explosive atmospheres - Part 15: Equipment EN 60079-15 -
protection by type of protection "n"
IEC 60127 series Miniature fuses EN 60127 series
ISO 965-1 -  ISO general purpose metric screw threads - - -
Tolerances – Part 1: Principles and basic data
ISO 965-3 -  ISO general purpose metric screw threads - - -
Tolerances – Part 3: Deviations for
constructional screw threads
ISO 2738 -  Sintered metal materials, excluding EN ISO 2738 -
hardmetals - Permeable sintered metal
materials - Determination of density, oil
content and open porosity
ISO 4003 -  Permeable sintered metal materials - EN 24003 -
Determination of bubble test pore size
ISO 4022 -  Permeable sintered metal materials - EN ISO 4022 -
Determination of fluid permeability
ANSI/ASME B 1.20.1 -  - -
Annex ZY
(informative)
Significant changes between this European Standard and EN 60079-1:2007
This European Standard supersedes EN 60079-1:2007.
The significant changes with respect to EN 60079-1:2007 are as listed below.

Type
Significant Changes Clause Minor and Extension Major
editorial technical
changes changes
Normative references 2 X
(Removal of the edition date from the reference for          IEC
60079-0)
Requirements for level of protection “da” 4.2 X
(Catalytic sensors for combustible gas detectors)
Requirements for level of protection “dc” 4.4, 15.5 X
(“Enclosed break” devices from IEC 60079-15)
Flameproof joints, General requirements 5.1 X
(Documentation clarification and examples of corrosion inhibiting
grease)
Flameproof joints, General requirements 5.1 X
(Specific Conditions of Use that joints are not intended to be
repaired)
Flameproof joints, General requirements 5.1 X
(Electroplating more than 0.008 mm think)
Non-threaded joints, Gap (i) 5.2.2 X
(Intentional gaps between surface for flanged joints)
Serrated joints 5.2.8 X
(Use and test requirements)
Multi-step joints 5.2.9 X
(Not less than 3 adjacent segments and two path changes)
Minimum width of joint and maximum gap for enclosures of groups Table 2  X
IIA and IIB
(Maximum gaps for flanged, cylindrical or spigot joints of 9,5 mm
minimum width and volume greater than 2,000 cm3)
Minimum width of joint and maximum gap for enclosures of groups I, Table 2, X
IIA, IIB and IIC Table 3
(ISO 80000-1 for constructional value rounding)
Cylindrical threaded joints Table 4 X
(ISO 965-1 standard in respect of thread form or quality of fit)
Taper threaded joints Table 5 X
(External and internal thread construction)
Cemented joints
6.1.2  C1
(Supplemental mechanical means of securement)
Cemented joints                                         6.1.2 X
(Evaluation criteria if there is leakage)
Fused glass joints 6.2 X
(Glass-to-metal joints)
- 5 - EN 60079-1:2014
Type
Significant Changes Clause Minor and Extension Major
editorial technical
changes changes
Thermal tests of breathing and draining devices 10.9.3.2 X
(Temperature class based on external surface temperature after the
10 min test period)
Test of the ability of the breathing and draining device to withstand 10.9.3.4 X
pressure
(Relocated from before thermal tests to after the non-transmission
test)
Ex component certificate 10.9.4 X
(Service temperature range for non-metallic enclosures per IEC
60079-0)
Fasteners and openings 11 X
(Relocation of blanking element content to Clauses 13.8 and C.2.3)
Fasteners and openings, Property class or yield stress 11.3 X
(Certificate specific condition of use)
Fasteners and openings 11.8 X
(Openings in the wall of the enclosure)
Materials 12.8   C2
(Material limitation in acetylene atmospheres)
Entries for flameproof enclosures, General 13.1 X
(Metric and NPT threaded entries)
Entries for flameproof enclosures, General 13.1 X
(Group I non-threaded joints)
Entries for flameproof enclosures, Non-threaded holes 13.3 X
(Group I application)
Entries for flameproof enclosures, Cable glands 13.4 X
(Group I application)
Cable glands, Conduit sealing devices 13.4,13.5 X
(Documentation to facilitate mounting)
Plugs and sockets and cable couplers 13.6.4  C3
(Load requirement for arc-quenching test)
Bushings 13.7 X
(Documentation to facilitate mounting)
Blanking elements 13.8 X
(Relocated from Clause 11)
Verification and tests Table 6 X
(Maximum surface temperature conditions)
Type tests 15 X
(Sequence and number of samples for tests)
Determination of explosion pressure, General 15.2.2.2 X
(Devices that can cause turbulence)
Determination of explosion pressure, General 15.2.2.2 X
(Number of tests for Group IIC)
Determination of explosion pressure, General 15.2.2.4 X
(Pressure pilling for Group IIB)
Determination of explosion pressure, General 15.2.2.5 X
(Equipment marked for a single gas)
Overpressure test, General 15.2.3 X
(Low ambient overpressure tests not required)

Type
Significant Changes Clause Minor and Extension Major
editorial technical
changes changes
Overpressure test – First method (static) 15.2.3.2 X
(3 times option when routine batch testing)
Overpressure test – First method (static) 15.2.3.2 X
(Adjustment for low ambient due to small size of equipment)
Overpressure test – Second method (dynamic) 15.2.3.3 X
(Number of tests to be made)
Test for non-transmission of an internal ignition 15.3 X
(Clarification regarding grease)
Reduction in length of a threaded joint for non-transmission test Table 9 X
(ISO 965-1 and 965-3 standards in respect of thread form and
quality of fit)
Test factors to increase pressure or test gap Table 10 X
(Group IIC adjustments for elevated ambients)
Test for non-transmission of an internal ignition, Groups I, IIA and IIB 15.3.2.3 X
(Number of tests to be made)
Test for non-transmission of an internal ignition, Group IIC testing by 15.3.3.2 X
increased gap
(Number of tests to be made)
Test for non-transmission of an internal ignition, Group IIC 15.3.3.4 X
(Oxygen enrichment of test gases)
Thermal tests of enclosures with breathing and draining devices 15.4.3.1 X
(Temperature class based on external surface temperature after the
10 min test period)
Tests for “dc” devices 15.5 X
(“Enclosed break” devices from IEC 60079-15)
Routine tests, General 16.1.2 X
(Adjustment for low ambient due to small size of equipment)
Routine tests, General 16.1.3 X
(Options when second method is chosen)
Routine tests, General 16.3 X
(Welded joint inspection options)
Routine tests, General 16.6 X
(Allowance for batch testing)
Switchgear for Group I 17.2.2, X
(Clarifying need for compliance with EPL Mb types of protection) 17.2.3
Non-metallic enclosures and non-metallic parts of enclosures, 19.1 X
General
(Exception for cemented joints)
Non-metallic enclosures and non-metallic parts of enclosures, 19.2 X
Resistance to tracking and creepage distances
(Reference to both IEC 60079-7 and or IEC 60079-15)
Non-metallic enclosures and non-metallic parts of enclosures, 19.3 X
Requirements for type tests
(Clarification of test sequence)

- 7 - EN 60079-1:2014
Type
Significant Changes Clause Minor and Extension Major
editorial technical
changes changes
Instructions 21 X
(Indication that repair of flamepaths is not intended)
Bushings C.2.1.4 X
(Documentation regarding numbers of cores)
Bushings C.2.1.4 X
(Criteria for non-transmission test)
Bushings C.2.1.4 X
(Evaluation criteria if there is leakage)
Flameproof joints, Threaded joints C.2.2.1 X
(Requirement options)
Flameproof joints, Non-threaded joints C.2.2.2 X
(Group I application)
Constructional requirements for Ex blanking elements C.2.3.1 X
(Relocated from Clause 11)
Constructional requirements for Ex blanking elements C.2.3.2, X
(Metric and NPT Ex blanking elements) C.2.3.3
Constructional requirements for Ex blanking elements C.2.3.4 X
(Group I non-threaded construction)
Sealing test, General C.3.1.1 X
(Allowance for re-tightening)
Cable glands and conduit sealing devices with sealing ring C.3.1.2 X
(Mandrel to be corrosion-resistant metal)
Type tests for Ex blanking elements, Torque test C.3.3.1 X
(Test-block to be steel)
Tightening torque values Table C.1 X
(Addition of < 16 mm thread size)
Tightening torque values Table C.2 X
(Addition of NPT thread sizes)
Ex component enclosure requirements D.3.8  C4
(Markings content)
Ex component enclosure requirements D.3.10 X
(Certificate content)
Utilization of an Ex component enclosure certificate to D.4.1 X
prepare an equipment certificate, Procedure
(Devices that can create significant turbulence)
Acceptable primary cells Table E.1 X
(Addition of Type B cells)
Acceptable primary cells Table E.1  C5
(Removal of Type T cells)
Acceptable secondary cells Table E.2 X
(Addition of Lithium type cells)
Prevention of excessive temperature and cell damage E.4.1.2 X
(Application of IEC 60079-11 requirement)
Prevention of inadvertent charging of a battery by other E.4.3 X
voltage sources in the enclosure
(Construction not requiring additional protection)

Type
Significant Changes Clause Minor and Extension Major
editorial technical
changes changes
Recharging of secondary cells inside flameproof enclosures E.5.1 X
(Additional battery options)
Introduction of an alternative risk assessment method Annex G X
encompassing equipment protection levels’ for Ex equipment
(Removal of previous Informative Annex)
Additional requirements for Flameproof enclosures with an Annex G X
internal source of release (containment system)
(Addition of new Normative Annex)
Requirements for machines with flameproof “d” enclosures Annex H X
fed from converters
(Addition of new Normative Annex)

Explanation of the Types of Significant 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.
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 – Supplemental mechanical means of securing the cemented joint shall not be defeated by the opening of doors or covers
that are intended to be opened during installation or maintenance. For example, in the images below for a luminaire
incorporating a cemented joint between the lens and the enclosure cover, the construction
shown in the second image would be in accordance with this requirement, while the
construction shown in the first image would not.

C2 – Addition of material limitations of enclosures of equipment and enclosures of Ex components for external mounting, if
constructed of copper or copper alloys, when used in explosive gas atmospheres containing acetylene (12.8).
C3 – Addition of power factor requirement for evaluating the ability of a plug and socket to remain flameproof during the arc-
quenching period while opening a test circuit (13.6.4).
C4 – Addition of marking requirements for Ex component enclosures, in addition to the requirements for marking of Ex
components given in IEC 60079-0 (D.3.8).
C5 – Removal of Type T cells as acceptable primary cells (Table E.1).

- 9 - EN 60079-1:2014
Annex ZZ
(informative)
Coverage of Essential Requirements of EC 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 EC Directive 94/9/EC:

– ER 1.0.1, ER 1.0.2 (partly), ER 1.0.3, ER 1.0.4 (partly), ER 1.0.5, ER 1.0.6
– ER 1.1
– ER 1.2.1 (partly), ER 1.2.2 (partly), ER 1.2.3, ER 1.2.6, ER 1.2.7, ER 1.2.8, ER 1.2.9
– ER 1.3.1, ER 1.3.4
– ER 1.4
– ER 1.5
– ER 1.6.4
– ER 2.0
– ER 2.1
– ER 2.2.1
– ER 2.3
Compliance with this standard provides one means of conformity with the specified essential
requirements of the Directive[s] concerned.

WARNING: Other requirements and other EC Directives may be applicable to the products
falling within the scope of this standard.

IEC 60079-1 ®
Edition 7.0 2014-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Explosive atmospheres –
Part 1: Equipment protection by flameproof enclosures “d”

Atmosphères explosives –
Partie 1: Protection du matériel par enveloppes antidéflagrantes «d»

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XD
ICS 29.260.20 ISBN 978-2-8322-1663-7

– 2 – IEC 60079-1:2014 © IEC 2014
CONTENTS
FOREWORD . 8
1 Scope . 16
2 Normative references . 16
3 Terms and definitions . 17
4 Level of protection (equipment protection level, EPL) . 19
4.1 General . 19
4.2 Requirements for level of protection “da” . 19
4.3 Requirements for level of protection “db” . 20
4.4 Requirements for level of protection “dc” . 20
4.4.1 General . 20
4.4.2 Construction of “dc” devices . 20
4.4.3 Tests for “dc” devices . 20
5 Flameproof joints . 21
5.1 General requirements . 21
5.2 Non-threaded joints . 22
5.2.1 Width of joints (L) . 22
5.2.2 Gap (i) . 22
5.2.3 Spigot joints. 22
5.2.4 Holes in joint surfaces . 23
5.2.5 Conical joints . 25
5.2.6 Joints with partial cylindrical surfaces (not permitted for Group IIC) . 25
5.2.7 Flanged joints for acetylene atmospheres . 26
5.2.8 Serrated joints . 26
5.2.9 Multi-step joints . 27
5.3 Threaded joints . 30
5.4 Gaskets (including O-rings) . 30
5.5 Equipment using capillaries . 32
6 Sealed joints. 32
6.1 Cemented joints . 32
6.1.1 General . 32
6.1.2 Mechanical strength. 32
6.1.3 Width of cemented joints . 33
6.2 Fused glass joints . 33
6.2.1 General . 33
6.2.2 Width of fused glass joints . 33
7 Operating rods . 33
8 Supplementary requirements for shafts and bearings. 34
8.1 Joints of shafts . 34
8.1.1 General . 34
8.1.2 Cylindrical joints . 34
8.1.3 Labyrinth joints . 34
8.1.4 Joints with floating glands . 34
8.2 Bearings . 36
8.2.1 Sleeve bearings . 36
8.2.2 Rolling-element bearings . 36

IEC 60079-1:2014 © IEC 2014 – 3 –
9 Light-transmitting parts . 36
10 Breathing and draining devices which form part of a flameproof enclosure . 37
10.1 General . 37
10.2 Openings for breathing or draining . 37
10.3 Composition limits . 37
10.4 Dimensions . 37
10.5 Elements with measurable paths . 37
10.6 Elements with non-measurable paths . 37
10.7 Removable devices . 38
10.7.1 General . 38
10.7.2 Mounting arrangements of the elements . 38
10.8 Mechanical strength . 38
10.9 Breathing devices and draining devices when used as Ex components . 38
10.9.1 General . 38
10.9.2 Mounting arrangements of the elements and components . 38
10.9.3 Type tests for breathing and draining devices used as Ex components . 38
10.9.4 Ex component certificate . 41
11 Fasteners and openings . 42
12 Materials . 43
13 Entries for flameproof enclosures . 44
13.1 General . 44
13.2 Threaded holes . 44
13.3 Non-threaded holes (for Group I only) . 44
13.4 Cable glands . 45
13.5 Conduit sealing devices . 45
13.6 Plugs and sockets and cable couplers . 46
13.7 Bushings . 47
13.8 Blanking elements. 47
14 Verification and tests . 47
15 Type tests . 48
15.1 General . 48
15.2 Tests of ability of the enclosure to withstand pressure . 49
15.2.1 General . 49
15.2.2 Determination of explosion pressure (reference pressure) . 49
15.2.3 Overpressure test . 52
15.3 Test for non-transmission of an internal ignition . 53
15.3.1 General . 53
15.3.2 Electrical equipment of Groups I, IIA and IIB. 55
15.3.3 Electrical equipment of Group lIC . 56
15.4 Tests of flameproof enclosures with breathing and draining devices . 57
15.4.1 General . 57
15.4.2 Tests of ability of the enclosure to withstand pressure . 57
15.4.3 Thermal tests . 58
15.4.4 Test for non-transmission of an internal ignition . 58
15.5 Tests for “dc” devices . 59
15.5.1 General . 59
15.5.2 Preparation of “dc” samples . 59
15.5.3 Test conditions for “dc” devices . 59

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16 Routine tests . 60
16.1 General . 60
16.2 Enclosures not incorporating a welded construction . 61
16.3 Enclosures incorporating a welded construction . 61
16.4 Bushings not specific to one flameproof enclosure . 61
16.5 Acceptance criteria . 61
16.6 Batch testing . 61
17 Switchgear for Group I . 62
17.1 General . 62
17.2 Means of isolation . 62
17.2.1 General . 62
17.3 Doors or covers . 62
17.3.1 Quick-acting doors or covers . 62
17.3.2 Doors or covers fixed by screws . 62
17.3.3 Threaded doors or covers . 63
18 Lampholders and Iamp caps . 63
18.1 General . 63
18.2 Device preventing lamps working loose . 63
18.3 Holders and caps for lamps with cylindrical caps. 63
18.4 Holders for lamps with threaded caps . 63
19 Non-metallic enclosures and non-metallic parts of enclosures . 63
19.1 General . 63
19.2 Resistance to tracking and creepage distances on internal surfaces of the
enclosure walls . 64
19.3 Requirements for type tests . 64
19.4 Test of erosion by flame . 64
20 Marking . 64
20.1 General . 64
20.2 Caution and warning markings . 65
20.3 Informative markings . 65
21 Instructions . 65
Annex A (normative)  Additional requirements for crimped ribbon elements and
multiple screen elements of breathing and draining devices . 66
Annex B (normative) Additional requirements for elements, with non-measurable
paths of breathing and draining devices . 67
B.1 Sintered metal elements . 67
B.2 Pressed metal wire elements . 67
B.3 Metal foam elements . 68
Annex C (normative) Additional requirements for flameproof entry devices . 69
C.1 General . 69
C.2 Constructional requirements . 69
C.2.1 Sealing methods . 69
C.2.2 Flameproof joints . 70
C.2.3 Constructional requirements for Ex blanking elements . 71
C.2.4 Constructional requirements for Ex thread adapters. 73
C.3 Type tests . 73
C.3.1 Sealing test . 73
C.3.2 Test of mechanical strength . 74

IEC 60079-1:2014 © IEC 2014 – 5 –
C.3.3 Type tests for Ex blanking elements . 75
C.3.4 Type tests for Ex thread adapters . 76
Annex D (normative) Empty flameproof enclosures as Ex components . 78
D.1 General . 78
D.2 Introductory remarks . 78
D.3 Ex component enclosure requirements . 78
D.4 Utilization of an Ex component enclosure certificate to prepare an equipment
certificate . 80
D.4.1 Procedure . 80
D.4.2 Application of the schedule of limitations . 80
Annex E (normative) Cells and batteries used in flameproof “d” enclosures . 81
E.1 Introductory remarks . 81
E.2 Acceptable electrochemical systems . 81
E.3 General requirements for cells (or batteries) inside flameproof enclosures . 82
E.4 Arrangement of safety devices . 82
E.4.1 Prevention of excessive temperature and cell damage . 82
E.4.2 Prevention of cell polarity reversal or reverse charging by another cell
in the same battery . 83
E.4.3 Prevention of inadvertent charging of a battery by other voltage sources
in the enclosure . 83
E.5 Recharging of secondary cells inside flameproof enclosures . 84
E.6 Rating of protection diodes and reliability of protection devices . 85
Annex F (informative) Mechanical properties for screws and nuts . 86
Annex G (normative) Additional requirements for flameproof enclosures with an
internal source of release (containment system) . 87
G.1 General . 87
G.2 Release conditions. 87
G.2.1 No release . 87
G.2.2 Limited release of a gas or vapour . 88
G.2.3 Limited release of a liquid . 88
G.3 Design requirements for the containment system . 88
G.3.1 General design requirements . 88
G.3.2 Infallible containment system . 88
G.3.3 Containment system with a limited release . 89
G.4 Type tests for the containment system . 89
G.4.1 Overpressure test . 89
G.4.2 Leakage test for an infallible containment system . 89
G.4.3 Leakage test for a containment system with a limited release . 90
Annex H (normative) Requirements for machines with flameproof “d” enclosures fed
from converters . 91
H.1 General . 91
H.2 Construction requirements for bearings . 91
H.3 Temperature requirements . 91
Bibliography . 92

Figure 1 – Example of construction for indirect checking of a flanged Group I
flameproof joint . 22
Figure 2 – Spigot joints . 23
Figure 3 – Holes in surfaces of flanged joints, example 1 . 24

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Figure 4 – Holes in surfaces of flanged joints, example 2 . 24
Figure 5 – Holes in surfaces of flanged joints, example 3 . 24
Figure 6 – Holes in surfaces of spigot joints, example 1 . 24
Figure 7 – Holes in surfaces of spigot joints, example 2 . 25
Figure 8 – Holes in surfaces of spigot joints, example 3 . 25
Figure 9 – Examples of joint constructions . 26
Figure 10 – Illustration of the requirements concerning gaskets – Example 1 . 31
Figure 11 – Illustration of the requirements concerning gaskets – Example 2 . 31
Figure 12 – Illustration of the requirements concerning gaskets – Example 3 . 31
Figure 13 – Illustration of the requirements concerning gaskets – Example 4 . 31
Figure 14 – Illustration of the requirements concerning gaskets – Example 5 . 31
Figure 15 – Illustration of the requirements concerning gaskets – Example 6 . 31
Figure 16 – Illustration of the requirements concerning gaskets – Example 7 . 32
Figure 17 – Example of cylindrical joint for shaft of rotating electrical
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