IEC/IEEE 60079-30-1:2015

IEC/IEEE 60079-30-1 ®
Edition 1.0 2015-09
INTERNATIONAL
STANDARD
colour
inside
Explosive atmospheres –
Part 30-1: Electrical resistance trace heating – General and testing requirements

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IEC/IEEE 60079-30-1 ®
Edition 1.0 2015-09
INTERNATIONAL
STANDARD
colour
inside
Explosive atmospheres –
Part 30-1: Electrical resistance trace heating – General and testing requirements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.260.20 ISBN 978-2-8322-2758-9

– 2 – IEC/IEEE 60079-30-1:2015
© IEC/IEEE 2015
CONTENTS
FOREWORD . 5
INTRODUCTION . 10
1 Scope . 11
2 Normative references . 15
3 Terms and definitions . 16
4 General requirements . 22
4.1 General . 22
4.2 Mechanical strength . 22
4.3 Terminations and connections . 23
4.4 Circuit protection requirements for branch circuits. 23
4.5 Temperature requirements . 23
4.5.1 General . 23
4.5.2 Stabilized design . 24
4.5.3 Controlled design. 24
5 Testing . 26
5.1 Type tests . 26
5.1.1 General . 26
5.1.2 Dielectric test . 26
5.1.3 Electrical insulation resistance test . 27
5.1.4 Flammability test . 27
5.1.5 Impact tests . 29
5.1.6 Deformation test . 32
5.1.7 Cold bend test . 32
5.1.8 Water resistance test . 33
5.1.9 Integral components resistance to water test . 33
5.1.10 Verification of rated output . 34
5.1.11 Thermal stability of electrical insulating material . 36
5.1.12 Thermal performance test . 36
5.1.13 Determination of maximum sheath temperature . 38
5.1.14 Verification of start-up current . 46
5.1.15 Verification of the electrical resistance of electrically conductive
covering . 46
5.1.16 Outdoor exposure test . 47
5.2 Routine tests. 47
5.2.1 Dielectric test . 47
5.2.2 Verification of rated output . 47
6 Marking . 47
6.1 Product markings for trace heaters . 47
6.2 Markings for field assembled components . 48
7 Documentation requirements . 48
7.1 General . 48
7.2 Circuit design documentation . 48
7.3 Trace heating system documentation . 49
7.3.1 General . 49

© IEC/IEEE 2015
7.3.2 For trace heating systems according to the product classification
method . 49
7.3.3 For trace heating systems according to stabilized design method . 49
7.3.4 For trace heating systems according to controlled design method . 49
7.4 Instructions for installation of trace heating system . 50
7.5 Instructions for commissioning . 50
7.6 Instructions for maintenance / repair or modification . 50
Annex A (informative) Type test matrix for EPLs Gb/Gc/Db/Dc (Refer to IEC 60079-14
for the relationship of EPLs to Zones) . 52
Annex B (informative) Checklist for installation . 53
Annex C (normative) Trace heater product design verification methodology . 54
C.1 General . 54
C.2 Design methodology and selection of trace heaters . 54
C.3 Stabilized design calculations . 54
C.4 Trace heater performance and equilibrium conditions . 55
C.5 Heat loss calculations . 57
C.6 Heat loss design safety factor . 58
C.7 Maximum temperature determination . 58
C.7.1 Theoretical pipe and sheath temperature calculations – Metallic
applications . 58
C.7.2 Theoretical vessel and sheath temperature calculations – Metallic
applications . 59
C.7.3 Sheath temperature – metallic applications utilizing a temperature
limiter control sensing the trace heater sheath or an artificial hot spot . 60
C.7.4 Theoretical sheath temperature calculations – Non-metallic applications . 60
C.7.5 Sheath temperature – non-metallic applications utilizing a temperature
limiter control sensing the trace heater sheath or an artificial hot spot . 62
Annex D (normative) Requirements for Division 1 and Division 2 trace heating
systems . 63
D.1 Application . 63
D.2 General . 63
D.3 Terminations and connections . 63
D.4 Control and temperature requirements . 63
D.4.1 General . 63
D.4.2 Stabilized design . 63
D.4.3 Controlled design. 64
D.4.4 Requirements for protective device in Divisions 1 and 2 . 64
D.5 Type tests . 64
D.5.1 Division 1 trace heating equipment . 64
D.5.2 Division 2 equipment . 65
D.6 Marking . 65
D.7 Instructions – Installation requirements . 65
Annex E (normative) Type test matrix for Division 1 and 2 explosive atmospheres . 67
Bibliography . 69

Figure 1 – Flammability test . 28
Figure 2 – Example of room temperature impact test . 30
Figure 3 – Example of minimum temperature impact test . 31
Figure 4 – Cold bend test . 33

– 4 – IEC/IEEE 60079-30-1:2015
© IEC/IEEE 2015
Figure 5 – Integral components resistance to water test . 34
Figure 6 – Verification of rated output . 35
Figure 7 – Maximum sheath temperature using product classification approach . 39
Figure 8 – Verification of sheath temperatures using pipe sculpture . 41
Figure 9 – Verification of sheath temperature, plate test . 44
Figure 10 – Verification of sheath temperature – plate test with serpentined sample . 44
Figure 11 – Plate test with two samples crossed over . 45
Figure 12 – Plate test with a single sample crossed over . 46
Figure C.1 – Equilibrium conditions for workpiece maintenance . 55
Figure C.2 – Equilibrium conditions for upper limit evaluation . 56

Table 1 – Application or exclusion of specific clauses of IEC 60079-0 . 11
Table 2 – Sheath temperature design conditions based on equipment protection levels
– Stabilized design approach . 24
Table 3 – Sheath temperature design conditions based on equipment protection levels
EPLs – Controlled design approach . 25
Table 4 – Test voltages for the dielectric test . 26
Table A.1 – Determination of test samples . 52
Table B.1 – Trace heater installation record – Example . 53
Table D.1 – Division trace heating systems . 63
Table D.2 – Sheath temperature design conditions – Stabilized design approach . 64
Table D.3 – Sheath temperature design conditions – With temperature control device . 64
Table E.1 – Applicable trace heater and trace heater pads and panels tests by
installation location . 67
Table E.2 – Applicable tests for integral components with trace heaters and trace
heater pads and panels. 68

© IEC/IEEE 2015
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EXPLOSIVE ATMOSPHERES –
Part 30-1: Electrical resistance trace heating –
General and testing requirements

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
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IEC/IEEE Publication or any other IEC or IEEE 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 implementation of this IEC/IEEE Publication may require use of
material covered by patent rights. By publication of this standard, no position is taken with respect to the
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rights, and the risk of infringement of such rights, is entirely their own responsibility.

– 6 – IEC/IEEE 60079-30-1:2015
© IEC/IEEE 2015
International Standard IEC/IEEE 60079-30-1 has been prepared by IEC technical committee
31: Equipment for explosive atmospheres, in cooperation with the Petroleum & Chemical
Industry Committee of the IEEE Industrial Applications Society under the IEC/IEEE Dual Logo
Agreement.
This publication is published as an IEC/IEEE Dual Logo standard.
NOTE A list of IEEE participants can be found at the following URL:
http://standards.ieee.org/downloads/60079/60079-30-1-2015/60079-30-1-2015_wg-participants.pdf .
This first edition of IEC/IEEE 60079-30-1 cancels and replaces the first edition of IEC 60079-
30-1 published in 2007 and constitutes a technical revision.
This edition includes the following significant changes, apart from the general revision and
updating of the first edition of IEC 60079-30-1 and harmonization with IEEE Std 515, with
respect to the previous edition:
• the inclusion of a minimum temperature impact test;
• the addition of a mechanical procedure in the thermal stability test;
• the inclusion of a thermal performance test to replace the thermal safety requirements;
• the inclusion of a second procedure utilizing a plate fixture for sheath temperature
determination;
• the inclusion of an ultraviolet and condensation test;
• the revision and significant expansion of documentation requirements;
• the addition of Annexes covering requirements for Divisions 1 and 2;
• the addition of a table covering the applicability of requirements from IEC 60079-0;
• the addition of an Annex covering trace heater product design verification methodology
(formerly located in IEC 60079-30-2);
• the further harmonization of this edition with several national standards.
The significance of changes between IEC 60079-30-1, Edition 1.0 (2007) and IEC/IEEE
60079-30-1, Edition 1.0 (2015) is as listed below:
Type
Changes Clause Minor and Extension Major
editorial technical
changes changes
Addition of clarification for the exclusion of EPLs Ga
1 X
and Da
Addition of requirements for the Division method of
1 X
area classification that may be applied by some users
Addition of table specifying the application or
1 X
exclusion of specific clauses of IEC 60079-0 Edition 6
For stabilized designs, a clarification for the need for
verification by testing and the addition of a table for 4.5.2 X
the specific requirements
For controlled designs, a clarification for the need for
verification by testing and the addition of a table for 4.5.3 X
the specific requirements
For controlled designs, clarifications and additions on
4.5.3 X
the separate requirements for Gb/Db and Gc/Dc
The requirements for calibration of the flammability
test fixture are replaced with equivalent requirements 5.1.4 X
for the energy levels of the test gases
Addition of a minimum temperature impact test 5.1.5  C1

© IEC/IEEE 2015
Type
Changes Clause Minor and Extension Major
editorial technical
changes changes
For thermal stability, the addition of a bending
5.1.11  C1
requirement on a mandrel
The replacement of the thermal safety procedure with
5.1.12  C2
a thermal performance procedure
The addition of a second procedure utilizing a plate
fixture for the systems method for maximum sheath 5.1.13.2  C3
temperature determination
Addition of outdoor exposure test 5.1.16  C4
Requirement changed for the marking of the minimum
6.1  C5
installation temperature
Addition of new markings requirements for field
6.2  C5
assembled components
Additions and changes to the documentation
7  C5
requirements
Addition of Annex Annex A X
Addition of Annex Annex B X
Addition of Annex specifying trace heating design
Annex C  C6
verification methodology, moved from IEC 60079-30-2
Addition of Annex for the Division method of area
Annex D X
classification that may be applied by some users
Addition of Annex for the Division method of area
Annex E X
classification that may be applied by some users
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.
Explanations:
A) Definitions
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.
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.

– 8 – IEC/IEEE 60079-30-1:2015
© IEC/IEEE 2015
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 – The requirements for additional mechanical testing have been included for
harmonization and for added safety.
C2 – The requirements for thermal performance have been included to recognize the
necessity for thermal stability of products in explosive atmospheres.
C3 – A second procedure utilizing a plate fixture has been included for sheath temperature
determination, which may be used in lieu of the sheath temperature verification part of
5.1.13.4.2.
C4 – An outdoor exposure test has been added to cover products that may be exposed to
sunlight and moisture in the intended application.
C5 – Additional marking and documentation requirements have been added to provide
additional information to the end user.
C6 – The trace heating design verification methodology has been added to align with the
evaluation requirements for the stabilized design and the controlled design methods of
maximum sheath temperature determination.
The text of this standard is based on the following IEC documents:
FDIS Report on voting
31/1191/FDIS 31/1201/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.
International standards are drafted in accordance with the rules given in the ISO/IEC
Directives, Part 2.
This standard is intended to be used in conjunction with IEC/IEEE 60079-30-2:2015,
Explosive atmospheres – Part 30-2: Electrical resistance trace heating – Application guide for
design, installation and maintenance.
A list of all parts of IEC 60079 series, under the general title Explosive atmospheres, can be
found on the IEC website.
© IEC/IEEE 2015
The IEC Technical Committee and IEEE Technical Committee have decided that the contents
of this publication will remain unchanged until the stability date indicated on the IEC website
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.
A bilingual version of this publication may be issued at a later date.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 10 – IEC/IEEE 60079-30-1:2015
© IEC/IEEE 2015
INTRODUCTION
IEC/IEEE 60079-30-1 is intended to provide a comprehensive overview of the essential
requirements and testing appropriate to electric surface heating equipment used in explosive
atmospheres. The requirements of this part of IEC 60079 are considered to be the minimum
requirements for equipment protection levels Gb, Gc, Db, and Dc in explosive atmospheres
for gases, dusts, and fibres/flyings. While some of this work already exists in national
standards or international standards, this standard has collated much of this existing work and
considerably added to it. This standard also contains the minimum requirements for users
applying the Division method of area classification.

© IEC/IEEE 2015
EXPLOSIVE ATMOSPHERES –
Part 30-1: Electrical resistance trace heating –
General and testing requirements

1 Scope
This part of IEC 60079 specifies general and testing requirements for electrical resistance
trace heaters for application in explosive atmospheres with the exclusion of those for EPL Ga
and Da. This standard covers trace heaters that comprise either factory or field (work-site)
assembled units, and which may be series trace heaters, parallel trace heaters, trace heater
pads, or trace heater panels that have been assembled and/or terminated in accordance with
the manufacturer’s instructions.
This standard also includes requirements for termination assemblies and control methods
used with trace heating systems. The explosive atmospheres referred to in this standard are
those defined in IEC 60079-10-1 and IEC 60079-10-2.
Annexes D and E outline the application of this standard for those users applying the Division
method of area classification.
This standard supplements and modifies the general requirements of IEC 60079-0, except as
indicated in Table 1. Where a requirement of this standard conflicts with a requirement of
IEC 60079-0, the requirement of this standard takes precedence.
Table 1 – Application or exclusion of specific clauses of IEC 60079-0
Electrical resistance trace heaters and
IEC 60079-0
integral components
Terminations as
separate
Ed. 6.0 Clause / Subclause title Group I and Group II Group III
components
(2011) (normative)
(informative)
1 Scope Applies Applies Applies
2 Normative references Applies Applies Applies
3 Terms and definitions Applies, Applies, Applies,
except ambient except ambient except ambient
temperature, see 3.1 temperature, see 3.1 temperature,
see 3.1
4 Equipment grouping Applies Applies Applies
4.1 Group I Applies Excluded Applies
4.2 Group II Applies, always IIC Excluded Applies
4.3 Group III Excluded Applies, outside of Applies, outside
thermal insulation of thermal
only, always IIIC insulation only
4.4 Equipment for a particular Excluded Excluded Applies
explosive atmosphere
5.1 Environmental influences Applies Applies Applies
5.1.1 Ambient temperature Replaced by 6.1e) Replaced by 6.1e) Applies, see 3.1
5.1.2 External source of heating or Applies Applies Applies
cooling
5.2 Service temperature Modified Modified Applies

– 12 – IEC/IEEE 60079-30-1:2015
© IEC/IEEE 2015
Electrical resistance trace heaters and
IEC 60079-0
integral components
Terminations as
separate
Ed. 6.0 Clause / Subclause title Group I and Group II Group III
components
(2011) (normative)
(informative)
5.3.1 Determination of maximum Replaced by 4.5 in Replaced by 4.5 in Applies
surface temperature conjunction with 5.1.13 conjunction with
5.1.13 only when
tested in accordance
with 5.1.13.3.
5.3.2.1 Group I electrical equipment Applies Excluded Applies
5.3.2.2 Group II electrical equipment Applies Excluded Applies
5.3.2.3.1 Group III electrical equipment, Excluded Applies, where the Applies
Maximum surface temperature maximum sheath
determined without a dust temperatures
layer determined by
IEC/IEEE 60079-30-
1 are used in place
of the method for
temperature
determination from
IEC 60079-0.
5.3.2.3.2 Group III electrical equipment Excluded Applies, where the Applies
Maximum surface temperature maximum sheath
with respect to dust layers temperature is
determined only for
those surfaces that
are specified to be
exposed to layers of
combustible dust.
Does not apply for
trace heaters
specified to be
covered by thermal
insulation.
5.3.3 Small component temperature Excluded Excluded Applies
for Group I and Group II
electrical equipment
6.1 Requirements for all electrical Applies Applies Applies
equipment – General
6.2 Mechanical strength Replaced by 4.2 Replaced by 4.2 When in direct
contact with the
trace heater, may
be substituted by
4.2
6.3 Opening times Excluded Excluded Applies
6.4 Circulating currents in Excluded Excluded Excluded
enclosures (e.g. of large
electrical machines)
6.5 Gasket retention Excluded Excluded Applies
6.6 Electromagnetic and ultrasonic Excluded Excluded Applies
radiating equipment
7.1.1 Non-metallic enclosures and Replaced by the last Replaced by the last Applies
non-metallic parts of paragraph of 4.1 paragraph of 4.1
enclosures – Applicability
7.1.2.1 Specification of materials, Replaced by the last Replaced by the last Applies
General paragraph of 4.1 paragraph of 4.1
7.1.2.2 Specification of materials, Replaced by the last Replaced by the last Applies
plastic materials paragraph of 4.1 paragraph of 4.1
7.1.2.3 Elastomers Replaced by the last Replaced by the last Applies
paragraph of 4.1 paragraph of 4.1
7.2 Thermal endurance Replaced by Replaced by Applies
requirements and tests requirements and

© IEC/IEEE 2015
Electrical resistance trace heaters and
IEC 60079-0
integral components
Terminations as
separate
Ed. 6.0 Clause / Subclause title Group I and Group II Group III
components
(2011) (normative)
(informative)
of this standard tests of this standard
7.3 Resistance to light Replaced by 5.1.16 for Replaced by 5.1.16 Applies
trace heaters and for trace heaters and
integral components integral components
specified for outdoor specified for outdoor
exposure exposure
7.4.1 Electrostatic charges on Excluded Excluded Applies
external non-metallic
materials, Applicability
7.4.2 Avoidance of a build-up of Excluded Excluded Applies
electrostatic charge on Group I
or Group II electrical
equipment
7.4.3 Avoidance of a build-up of Excluded Excluded Applies
electrostatic charge on
equipment for Group III
7.5 Accessible metal parts Excluded Excluded Applies
8.1 Material composition Excluded Excluded Applies
8.2 Group I Excluded Excluded Applies
8.3 Group II Excluded Excluded Applies
8.4 Group III Excluded Excluded Applies
9 Fasteners Excluded Excluded Applies
10 Interlocking devices Excluded Excluded Applies
11 Bushings Excluded Excluded Applies
12 Materials used for cementing Replaced by the last Replaced by the last Applies
paragraph of 4.1 paragraph of 4.1
13 Ex Components Applies Applies Applies
14 Connection facilities and Covered by the Covered by the Applies
termination compartments requirements of this requirements of this
standard standard
15 Connection facilities for Replaced by 5.1.15 Replaced by 5.1.15 Applies
earthing and bonding
conductors
16 Entries into enclosures Excluded Excluded Applies
17 Supplementary requirements Excluded Excluded Excluded
for rotating electrical machines
18 Supplementary requirements Excluded Excluded Excluded
for switchgear
19 Supplementary requirements Excluded Excluded Applies
for fuses
20 Supplementary requirements Excluded Excluded Applies
for plugs and sockets
21 Supplementary requirements Excluded Excluded Excluded
for luminaires
22 Supplementary requirements Excluded Excluded Excluded
for caplights and handlights
23 Equipment incorporating cells Excluded Excluded Applies
and batteries
24 Documentation Applies Applies Applies
25 Compliance of prototype or Applies Applies Applies

– 14 – IEC/IEEE 60079-30-1:2015
© IEC/IEEE 2015
Electrical resistance trace heaters and
IEC 60079-0
integral components
Terminations as
separate
Ed. 6.0 Clause / Subclause title Group I and Group II Group III
components
(2011) (normative)
(informative)
sample with documents
26.1 General Applies Applies Applies
26.2 Test configuration Applies Applies. Applies
26.3 Tests in explosive test Excluded Excluded Applies
mixtures
26.4 Tests of enclosures Excluded Excluded Applies
26.4.1 Order of tests Excluded Excluded Applies
26.4.1.1 Metallic enclosures, metallic Excluded Excluded Applies
parts of enclosures and glass
parts of enclosures
26.4.1.2 Non-metallic enclosures or Excluded Excluded Applies
non-metallic parts of
enclosures
26.4.2 Resistance to impact Replaced by 5.1.5 Replaced by 5.1.5 Applies
26.4.3 Drop test Excluded Excluded Excluded
26.4.4 Acceptance criteria Replaced by 5.1.5 Replaced by 5.1.5 Applies
26.4.5 Degree of protection by Replaced by 5.1.8 Replaced by 5.1.8 Applies
enclosure and/or 5.1.9 and/or 5.1.9.
26.5 Thermal tests Modified. Modified Applies
26.5.1 Temperature measurement Replaced by 5.1.13 Replaced by 5.1.13 Applies
26.5.2 Thermal shock test Excluded Excluded Applies
26.5.3 Small component ignition test Excluded Excluded Applies
26.6 Torque test for bushings Excluded Excluded Applies
26.7 Non-metallic enclosures or Excluded Excluded Applies
non-metallic parts of
enclosures
26.8 Thermal endurance to heat Replaced by 5.1.11 Replaced by 5.1.11 Applies
26.9 Thermal endurance to cold Replaced by 5.1.7 Replaced by 5.1.7 Applies
26.10 Resistance to light Replaced by 5.1.16for Replaced by 5.1.16 Applies
trace heaters and for trace heaters and
integral components integral components
specified for outdoor specified for outdoor
exposure exposure
26.11 Resistance to chemical agents Applies for Group I Excluded Applies
for Group I electrical
equipment
26.12 Earth continuity Excluded Excluded Applies
26.13 Surface resistance test of parts Excluded Excluded Applies
of enclosures of non-metallic
materials
26.14 Measurement of capacitance Excluded Excluded Applies
26.15 Verification of ratings of Excluded Excluded Excluded
ventilating fans
26.16 Alternative qualification of Excluded Excluded Applies
elastomeric sealing O-rings
27 Routine tests Applies Applies Applies
28 Manufacturers responsibility Applies Applies Applies
29 Marking Modified Modified Applies

© IEC/IEEE 2015
Electrical resistance trace heaters and
IEC 60079-0
integral components
Terminations as
separate
Ed. 6.0 Clause / Subclause title Group I and Group II Group III
components
(2011) (normative)
(informative)
30 Instructions Modified Modified Applies
Annex A Supplementary requirements Excluded Excluded Applies
for Ex cable glands
Annex B Requirements for Ex Excluded Excluded Applies
components
Annex C Example of rig for resistance to Replaced by 5.1.5 Replaced by 5.1.5 Applies
impact test
Annex D Motors supplied by converters Excluded Excluded Excluded
Annex E Temperature rise testing of Excluded Excluded Excluded
electric machines
Annex F Guideline flowchart for tests of Excluded Excluded Applies
non-metallic enclosures or
non-metallic parts of
enclosures (26.4)
NOTE 1 Clause numbers in the three right-hand columns of this table refer to IEC/IEEE 60079-30-1
NOTE 2 The clause number in the above table is shown for information only. The applicable requirements of
IEC 60079-0 are identified by the clause title which is normative.
Applies: this requirement of IEC 60079-0 is applied without change.
Excluded: this requirement of IEC 60079-0 does not apply.
Modified: this requirement of IEC 60079-0 is modified as detailed in this standard.

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 60050-151:2001, International Electrotechnical Vocabulary – Part 151: Electrical and
magnetic devices
IEC 60050-426:2008, International Electrotechnical Vocabulary – Part 426: Equipment for
explosive atmospheres
IEC 60079-0:2011, Explosive atmospheres – Part 0: Equipment – General requirements
IEC 60695-11-3, Fire hazard testing – Part 11-3: Test flames – 500 W flames – Apparatus and
confirmational test methods
ISO 4582, Plastics – Determination of changes in colour and variation
...