IEC 60079-10-1:2015

IEC 60079-10-1 ®
Edition 2.0 2015-09
REDLINE VERSION
INTERNATIONAL
STANDARD
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inside
Explosive atmospheres –
Part 10-1: Classification of areas – Explosive gas atmospheres

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IEC 60079-10-1 ®
Edition 2.0 2015-09
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Explosive atmospheres –
Part 10-1: Classification of areas – Explosive gas atmospheres

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.260.20 ISBN 978-2-8322-2887-6

– 2 – IEC 60079-10-1:2015 RLV © IEC 2015

CONTENTS
FOREWORD . 6

INTRODUCTION . 9

1 Scope . 10

2 Normative references . 11

3 Terms and definitions . 11

4 General . 16

4.1 Safety principles . 16

4.2 Area classification objectives . 17
4.3 Explosion risk assessment . 17
4.4 Competence of Personnel . 18
5 Area classification procedure methodology . 18
5.1 General . 18
5.2 Classification by sources of release method . 19
5.3 Use of industry codes and national standards . 19
5.4 Simplified methods . 19
5.4.1 Release rate of gas or vapour .
5.4.2 Lower explosive limit (LEL) .
5.4.3 Ventilation .
5.4.4 Relative density of the gas or vapour when it is released .
5.4.5 Other parameters to be considered .
5.4.6 Illustrative examples .
5.5 Combination of methods . 20
6 Release of flammable substance . 20
6.1 General . 20
6.2 Sources of release . 20
6.3 Forms of release . 22
6.3.1 General . 22
6.3.2 Gaseous release . 22
6.3.3 Liquefied under pressure . 23
6.3.4 Liquefied by refrigeration . 23
6.3.5 Aerosols . 23
6.3.6 Vapours . 23

6.3.7 Liquid releases . 24
6.4 Ventilation (or air movement) and dilution . 24
6.5 Main types of ventilation . 25
6.5.1 General . 25
6.5.2 Natural ventilation. 25
6.5.3 Artificial ventilation . 26
6.5.4 Degree of dilution . 27
7 Type of zone . 28
7.1 General . 28
7.2 Influence of grade of the source of release . 28
7.3 Influence of dilution . 28
7.4 Influence of availability of ventilation . 28
8 Extent of zone . 29
9 Documentation . 32

9.1 General . 32

9.2 Drawings, data sheets and tables . 33

Annex A (informative) Suggested presentation of hazardous areas . 34

A.1 Hazardous area zones – Preferred symbols . 34

A.2 Hazardous area suggested shapes . 39

Annex B (informative) Examples of sources of release and release rate Estimation of

sources of release . 42

B.1 Symbols . 42

B.2 Process plant Examples of grade of release . 42

B.2.1 General . 42
B.2.2 Sources giving a continuous grade of release . 43
B.2.3 Sources giving a primary grade of release . 43
B.2.4 Sources giving a secondary grade of release . 43
B.3 Assessment of grades of release . 43
B.4 Summation of releases . 44
B.5 Hole size and source radius . 45
B.6 Forms of release . 46
B.7 Release rate . 48
B.7.1 General . 48
B.7.2 Estimation of Release Rate . 49
B.7.3 Release rate of evaporative pools . 53
B.8 Examples of estimating release rate .
B.8 Release from openings in buildings . 57
B.8.1 General . 57
B.8.2 Openings as possible sources of release . 57
B.8.3 Openings classification . 57
Annex B (informative) Ventilation .
Annex C (informative) Ventilation guidance . 75
C.1 Symbols . 75
C.2 General . 76
C.3 Assessment of ventilation and dilution and its influence on hazardous area . 76
C.3.1 General . 76
C.3.2 Effectiveness of ventilation . 77
C.3.3 Criteria for dilution . 77
C.3.4 Assessment of ventilation velocity . 78

C.3.5 Assessment of the degree of dilution . 79
C.3.6 Dilution in a room . 80
C.3.7 Criteria for availability of ventilation . 82
C.4 Examples of ventilation arrangements and assessments . 83
C.4.1 Introduction . 83
C.4.2 Jet release in a large building . 83
C.4.3 Jet release in a small naturally ventilated building . 84
C.4.4 Jet release in a small artificially ventilated building . 84
C.4.5 Release with low velocity . 85
C.4.6 Fugitive emissions . 86
C.4.7 Local ventilation-extraction . 86
C.5 Natural Ventilation in buildings . 87
C.5.1 General . 87
C.5.2 Wind induced ventilation . 87

– 4 – IEC 60079-10-1:2015 RLV © IEC 2015

C.5.3 Buoyancy induced ventilation. 88

C.5.4 Combination of the natural ventilation induced by wind and buoyancy . 90

Annex D (informative) Estimation of hazardous zones. 92

D.1 General . 92

D.2 Estimating types of the zones . 92

D.3 Estimating the extent of the hazardous zone . 92

Annex E (informative) Examples of hazardous area classification . 95

E.1 General . 95

E.2 Examples . 96

E.3 Example case study for area classification . 124
Annex F (informative) Schematic approach to classification of hazardous areas . 141
F.1 Schematic approach to classification of hazardous areas . 141
F.2 Schematic approach to classification of hazardous areas . 142
F.3 Schematic approach to classification of hazardous areas . 143
F.4 Schematic approach to classification of hazardous areas . 144
Annex G (informative) Flammable mists . 145
Annex H (informative) Hydrogen . 147
Annex I (informative) Hybrid mixtures . 149
I.1 General . 149
I.2 Use of ventilation . 149
I.3 Concentration limits . 149
I.4 Chemical reactions . 149
I.5 Energy/Temperature limits . 149
I.6 Zoning requirements . 149
Annex J (informative) Useful equations in support to hazardous area classification . 150
J.1 General . 150
J.2 Dilution with air of a flammable substance release . 150
J.3 Estimate of the time required to dilute a flammable substance release . 150
Annex K (informative) Industry codes and national standards . 152
K.1 General . 152
Bibliography . 154

Figure C.1 A.1 – Preferred symbols for hazardous area zones . 34
Figure A.2 – Gas/vapour at low pressure (or at high pressure in case of unpredictable

release direction) . 39
Figure A.3 – Gas/vapour at high pressure . 39
Figure A.4 – Liquefied gas . 40
Figure A.5 – Flammable liquid (non boiling evaporative pool) . 41
Figure B.1 – Forms of release . 47
Figure B.2 – Volumetric evaporation rate of liquids . 54
Figure C.1 – Chart for assessing the degree of dilution . 79
Figure C.2 – Schematic approach to the classification of hazardous areas.
Figure C.2 – Self diffusion of an unimpeded high velocity jet release . 84
Figure C.3 – Supply only ventilation . 85
Figure C.4 – Supply and extraction ventilation . 85
Figure C.5 – Local extraction ventilation . 87

Figure C.6 – Volumetric flow rate of fresh air per m of equivalent effective opening

area . 90

Figure C.7 – Example of opposing ventilation driving forces . 91

Figure D.1 – Chart for estimating hazardous area distances . 93

Figure E.1 – Degree of dilution (Example No. 1) . 98

Figure E.2 – Hazardous distance (Example No. 1) . 99

Figure E.3 – Zone classification (Example No. 1) . 99

Figure E.4 – Degree of dilution (Example No. 2) . 102

Figure E.5 – Hazardous distance (Example No. 2) . 103

Figure E.6 – Degree of dilution (Example No. 3) . 106
Figure E.7 – Hazardous distance (Example No. 3) . 107
Figure E.8 – Zones classification (Example No. 3) . 108
Figure E.9 – Degree of dilution (Example No. 4) . 111
Figure E.10 – Hazardous distance (Example No. 4) . 112
Figure E.11 – Zones classification (Example No. 4) . 112
Figure E.12 – Degree of dilution (Example No. 5) . 116
Figure E.13 – Hazardous distance (Example No. 5) . 117
Figure E.14 – Enclosed compressor handling natural gas . 133
Figure E.15 – Example of area classification for a compressor facility handling natural
gas (elevation) . 139
Figure E.16 – Example of area classification for a compressor facility handling natural
gas (plan) . 140
Figure F.1 – Schematic approach to classification . 141
Figure F.2 – Schematic approach to classification for continuous grade releases . 142
Figure F.3 – Schematic approach to classification for primary grade releases . 143
Figure F.4 – Schematic approach to classification for secondary grade releases . 144

Table C.1 A.1 − Hazardous area classification data sheet – Part I: Flammable material
substance list and characteristics . 35
Table C.2 A.2 − Hazardous area classification data sheet − Part II: List of sources of
release . 37
Table B.1 – Influence of independent ventilation on type of zone .
Table B.1 – Suggested hole cross sections for secondary grade of releases . 46

Table B.2 – Procedure for summation of multiple releases within location V .
o
Table B.2 – Effect of hazardous zones on openings as possible sources of release . 58
Table B.3 – Procedure for summation of multiple primary grade releases .
Table C.1 – Indicative outdoor ventilation velocities (u ) . 79
w
Table D.1 – Zones for grade of release and effectiveness of ventilation . 92
Table E.1 – Compressor facility handling natural gas . 134
Table E.2 – Hazardous area classification data sheet − Part I: Flammable substance
list and characteristics . 136
Table E.3 – Hazardous area classification data sheet − Part II: List of sources of
release (1 of 2) . 137
Table K.1 – Examples of codes and standards . 153

– 6 – IEC 60079-10-1:2015 RLV © IEC 2015

INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
EXPLOSIVE ATMOSPHERES –
Part 10-1: Classification of areas –

Explosive gas atmospheres
FOREWORD
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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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.
This redline version of the official IEC Standard allows the user to identify the changes
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International Standard IEC 60079-10-1 has been prepared by subcommittee 31J:
Classification of hazardous areas and installation requirements, of IEC technical committee

31: Equipment for explosive atmospheres.

This second edition of IEC 60079-10-1 cancels and replaces the first edition, published in

2008, and constitutes a technical revision. The significant technical changes with respect to

the previous edition are as follows:

Type
Minor
Major
and
Changes Clause Extension technical
editorial
changes
changes
Complete restructuring and dividing into
sections to identify possible methodologies Main
for classifying hazardous areas and to body of X X X
provide further explanation on specific the text
assessment factors
Introducing new terms and the definitions 3 X
Introducing clauses for alternative methods
5 X X
of area classification
Updating examples for presentation of
Annex A X X
hazardous area classification
Updating calculations for release rate Annex B X X
Complete re-write with a new approach
based upon the degree of dilution instead Annex C X X
of the degree of ventilation
Introduced as a new Annex for zone
Annex D X
extents
Updated with new examples to explain the
methodology set forth in Annexes A, B, C
Annex E X
and D
Update of the flow chart illustrating the
area classification procedure by dividing it
Annex F X
into four sections
Introduced as a new Annex on hydrogen Annex H X
Introduced as a new Annex on hybrid
Annex I X
mixtures
Introduced as a new Annex with
Annex J X
supplementary equations
Introduced as a new Annex for reference to
national and industry codes with specific Annex K X
examples of hazardous area classification

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.

– 8 – IEC 60079-10-1:2015 RLV © IEC 2015

Explanations:
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.

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.
Major technical changes addition of technical requirements
increase of technical requirements
These are changes to technical requirements (addition, increase of the level or removal).
NOTE These changes represent current technological knowledge. However, these changes should not normally
have an influence on equipment already placed on the market.
The text of this standard is based on the following documents:
FDIS Report on voting
31J/253/FDIS 31J/256/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 of the IEC 60079 series, 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 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.
The contents of the corrigendum of November 2015 have been included in this copy.
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.
INTRODUCTION
In areas where dangerous quantities and concentrations of flammable gas or vapour may

arise, protective measures are need to be applied in order to reduce the risk of explosions.

This part of IEC 60079 sets out the essential criteria against which the ignition hazards can
be assessed, and gives guidance on the design and control parameters which can be used in
order to reduce such hazards.
– 10 – IEC 60079-10-1:2015 RLV © IEC 2015

EXPLOSIVE ATMOSPHERES –
Part 10-1: Classification of areas –

Explosive gas atmospheres
1 Scope
This part of IEC 60079 is concerned with the classification of areas where flammable gas or
vapour or mist hazards (see Notes 1, 2 and 3) may arise and may then be used as a basis to
support the proper selection and installation of equipment for use in hazardous areas.
It is intended to be applied where there may be an ignition hazard due to the presence of
flammable gas or vapour, mixed with air under normal atmospheric conditions (see Note 4),
but it does not apply to:
a) mines susceptible to firedamp;
b) the processing and manufacture of explosives;
c) catastrophic failures or rare malfunctions which are beyond the concept of abnormality
dealt with in this standard (see Note 5 3.7.3 and 3.7.4);
d) rooms used for medical purposes;
e) commercial and industrial applications where only low pressure fuel gas is used for
appliances e.g. for cooking, water heating and similar uses, where the installation is
compliant with relevant gas codes;
f) domestic premises;
g) areas where a hazard may arise due to the presence of combustible dusts or fibres
combustible flyings but the principles may be used in assessment of a hybrid mixture
(refer also IEC 61241-10 / IEC 60079-10-2).
This standard does not take into account the effects of consequential damage.
Definitions and explanations of terms are given together with the main principles and
procedures relating to hazardous area classification.
For detailed recommendations regarding the extent of the hazardous areas in specific
industries or applications, reference may be made to national or industry codes relating to
those applications.
NOTE Additional guidance on hybrid mixtures is provided in Annex I.
NOTE 1 Flammable mists may form or be present at the same time as flammable vapour.
Liquids not considered to be hazardous in terms of this standard (due to the flash point),
when released under pressure may also generate flammable mists. In such case, the strict
application of area classification for gases and vapours the details in this standard may not be
appropriate as the basis for selection of equipment. Flammable mists may also form when
liquids not considered to be a hazard due to the high flash point are released under pressure.
In these cases the classifications and details given in this standard do not apply. Information
on flammable mists is provided in Annex G.
NOTE 2 The use of IEC 60079-14 for selection of equipment and installations is not required for mist hazards.
NOTE 3 For the purpose of this standard, an area is a three-dimensional region or space.

NOTE 4 Atmospheric conditions include variations above and below reference levels of 101,3

kPa (1 013 mbar) and 20 °C (293 K), provided that the variations have a negligible effect on

the explosion properties of the flammable materials substances.

NOTE 5 Catastrophic failure in this context is applied, for example, to the rupture of a process vessel or pipeline

and events that are not predictable.

NOTE 6 In any process plant, irrespective of size, there may be numerous sources of ignition

apart from those associated with equipment. Appropriate precautions will be necessary to

ensure safety in this context. This standard may be used is applicable with judgement for

other ignition sources.
This standard does not take into account the consequences of ignition of an explosive
atmosphere.
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 60050-426, International Electrotechnical Vocabulary (IEV) – Part 426: Equipment for
explosive atmospheres
IEC 60079-0, Explosive atmospheres – Part 0: Equipment – General requirements
IEC 60079-4, Electrical apparatus for explosive gas atmospheres – Part 4: Method of test for
ignition temperature
IEC 60079-4A, First supplement to IEC 60079-4 (1966), Electrical apparatus for explosive gas
atmospheres – Part 4: Method of test for ignition temperature
IEC 60079-14, Explosive atmospheres – Part 14: Electrical installations design, selection and
erection
IEC 60079-20, Electrical apparatus for explosive gas atmospheres – Part 20: Data for
flammable gases and vapours, relating to the use of electrical apparatus
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
explosive atmosphere
mixture with air, under atmospheric conditions, of flammable substances in the form of gas,
vapour, dust, fibres, or flyings which, after ignition, permits self-sustaining flame propagation
[SOURCE: IEC 60079-0:2013, 3.30]
3.2
explosive gas atmosphere
mixture with air, under atmospheric conditions, of flammable substances in the form of gas or
vapour, which, after ignition, permits self-sustaining flame propagation

– 12 – IEC 60079-10-1:2015 RLV © IEC 2015

Note 1 to entry: Although a mixture which has a concentration above the upper explosive flammable limit (UEL

UFL) is not an explosive gas atmosphere, it can readily become so and, in certain cases generally for area
classification purposes, it is advisable to consider it as an explosive gas atmosphere.

Note 2 to entry: There are some gases and vapours which are explosive with the concentration of 100 % (e.g.

acetylene, CAS no. 74-86-2, C H ; monovinyl acetylene, CAS no. 689-97-4, C H ; 1-propyl nitrate (vapour), CAS
2 2 4 4
no. 627-13-4, CH (CH ) NO ; isopropyl nitrate (vapour), CAS no. 1712-64-7, (CH ) CH ONO ; ethylene oxide

3 2 2 3 3 2 2
(vapour), CAS no. 75-21-8, (CH ) O; hydrazine (vapour), CAS no. 302-01-2, H N .
2 2 4 2
[SOURCE: IEC 60079-0:2013, 3.32, modified (addition of Notes to entry)]

3.3
hazardous areas and zones
3.3.1
hazardous area (on account of explosive gas atmospheres)
an area in which an explosive gas atmosphere is or may be expected to be present, in
quantities such as to require special precautions for the construction, installation and use of
equipment
Note 1 to entry: The interior of many items of process equipment are commonly considered as a hazardous area
even though a flammable atmosphere may not normally be present to account for the possibility of air entering the
equipment. Where specific controls such as inerting are used the interior of process equipment may not need to be
classified as a hazardous area.
3.3.2
non-hazardous area (on account of explosive gas atmospheres)
an area in which an explosive gas atmosphere is not expected to be present in quantities
such as to require special precautions for the construction, installation and use of equipment
3.3.3
zones
hazardous area are classified into zones classification based upon the frequency of the
occurrence and duration of an explosive gas atmosphere
3.3.4
zone 0
an area in which an explosive gas atmosphere is present continuously or for long periods or
frequently
Note 1 to entry: Both “long” and “frequently” are the terms which are intended to describe a very high likelihood of
a potentially explosive atmosphere in the area. In that respect, those terms do not necessarily need to be
quantified.
3.3.5
zone 1
an area in which an explosive gas atmosphere is likely to occur periodically or occasionally in

normal operation
3.3.6
zone 2
an area in which an explosive gas atmosphere is not likely to occur in normal operation but, if
it does occur, it will persist exist for a short period only
Note 1 to entry: Indications of the frequency of the occurrence and duration may be taken from codes relating to
specific industries or applications.
[SOURCE: IEC 60050-426:2009, 426-03-05]
3.3.7
extent of zone
distance in any direction from the source of release to where a gas/air mixture will be diluted
by air to a concentration below the lower flammable limit

3.4
releases
3.4.1
source of release
a point or location from which a flammable gas, vapour, mist or liquid may be released into

the atmosphere so that an explosive gas atmosphere could be formed

[SOURCE: IEC 60050-426:2009, 426-03-06, modified (addition of "mist")]

3.10
grades of release
there are three basic grades of release, as listed below in order of decreasing frequency and
likelihood of the explosive gas atmosphere being present:
a) continuous grade;
b) primary grade;
c) secondary grade.
A source of release may give rise to any one of these grades of release, or to a combination
of more than one
3.4.2
continuous grade of release
release which is continuous or is expected to occur frequently or for long periods
Note 1 to entry: Both “frequently” and “long” are the terms which are intended to describe a very high likelihood of
a potential release. In that respect, those terms do not necessarily need to be quantified.
3.4.3
primary grade of release
release which can be expected to occur periodically or occasionally during normal operation
3.4.4
secondary grade of release
release which is not expected to occur in normal operation and, if it does occur, is likely to do
so only infrequently and for short periods
3.4.5
release rate
quantity of flammable gas, liquid, vapour or mist emitted per unit time from the source of
release
3.5
ventilation and dilution
3.5.1
ventilation
movement of air and its replacement with fresh air due to the effects of wind, temperature
gradients, or artificial means (for example, fans or extractors)
3.5.2
dilution
the mixing of flammable vapour or gas with air which, over time, will reduce the flammable
concentration
3.5.3
dilution volume
the volume in the vicinity of a source of release where the concentration of flammable gas or
vapour is not diluted to a safe level

– 14 – IEC 60079-10-1:2015 RLV © IEC 2015

Note 1 to entry: In certain instances, th
...

IEC 60079-10-1 ®
Edition 2.0 2015-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Explosive atmospheres –
Part 10-1: Classification of areas – Explosive gas atmospheres

Atmosphères explosives –
Partie 10-1: Classement des emplacements – Atmosphères explosives gazeuses

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IEC 60079-10-1 ®
Edition 2.0 2015-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Explosive atmospheres –
Part 10-1: Classification of areas – Explosive gas atmospheres

Atmosphères explosives –
Partie 10-1: Classement des emplacements – Atmosphères explosives gazeuses

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.260.20 ISBN 978-2-8322-3112-8

– 2 – IEC 60079-10-1:2015 © IEC 2015
CONTENTS
FOREWORD . 6
INTRODUCTION . 9
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 11
4 General . 15
4.1 Safety principles . 15
4.2 Area classification objectives . 16
4.3 Explosion risk assessment . 16
4.4 Competence of personnel . 17
5 Area classification methodology . 17
5.1 General . 17
5.2 Classification by sources of release method . 18
5.3 Use of industry codes and national standards . 18
5.4 Simplified methods . 18
5.5 Combination of methods . 19
6 Release of flammable substance . 19
6.1 General . 19
6.2 Sources of release . 19
6.3 Forms of release . 20
6.3.1 General . 20
6.3.2 Gaseous release . 21
6.3.3 Liquefied under pressure . 21
6.3.4 Liquefied by refrigeration . 22
6.3.5 Aerosols . 22
6.3.6 Vapours . 22
6.3.7 Liquid releases . 22
6.4 Ventilation (or air movement) and dilution . 23
6.5 Main types of ventilation . 23
6.5.1 General . 23
6.5.2 Natural ventilation. 23
6.5.3 Artificial ventilation . 24
6.5.4 Degree of dilution . 25
7 Type of zone . 26
7.1 General . 26
7.2 Influence of grade of the source of release . 26
7.3 Influence of dilution . 27
7.4 Influence of availability of ventilation . 27
8 Extent of zone . 27
9 Documentation . 28
9.1 General . 28
9.2 Drawings, data sheets and tables . 28
Annex A (informative) Suggested presentation of hazardous areas . 30
A.1 Hazardous area zones – Preferred symbols . 30
A.2 Hazardous area suggested shapes . 33

Annex B (informative) Estimation of sources of release. 35
B.1 Symbols . 35
B.2 Examples of grade of release . 35
B.2.1 General . 35
B.2.2 Sources giving a continuous grade of release . 35
B.2.3 Sources giving a primary grade of release . 36
B.2.4 Sources giving a secondary grade of release . 36
B.3 Assessment of grades of release . 36
B.4 Summation of releases . 37
B.5 Hole size and source radius . 38
B.6 Forms of release . 40
B.7 Release rate . 41
B.7.1 General . 41
B.7.2 Estimation of Release Rate . 41
B.7.3 Release rate of evaporative pools . 44
B.8 Release from openings in buildings . 46
B.8.1 General . 46
B.8.2 Openings as possible sources of release . 46
B.8.3 Openings classification . 46
Annex C (informative) Ventilation guidance . 48
C.1 Symbols . 48
C.2 General . 49
C.3 Assessment of ventilation and dilution and its influence on hazardous area . 49
C.3.1 General . 49
C.3.2 Effectiveness of ventilation . 50
C.3.3 Criteria for dilution . 50
C.3.4 Assessment of ventilation velocity . 51
C.3.5 Assessment of the degree of dilution . 52
C.3.6 Dilution in a room . 53
C.3.7 Criteria for availability of ventilation . 55
C.4 Examples of ventilation arrangements and assessments . 56
C.4.1 Introduction . 56
C.4.2 Jet release in a large building . 56
C.4.3 Jet release in a small naturally ventilated building . 57
C.4.4 Jet release in a small artificially ventilated building . 57
C.4.5 Release with low velocity . 58
C.4.6 Fugitive emissions . 59
C.4.7 Local ventilation-extraction . 59
C.5 Natural Ventilation in buildings . 60
C.5.1 General . 60
C.5.2 Wind induced ventilation . 60
C.5.3 Buoyancy induced ventilation. 61
C.5.4 Combination of the natural ventilation induced by wind and buoyancy . 63
Annex D (informative) Estimation of hazardous zones. 65
D.1 General . 65
D.2 Estimating types of the zones . 65
D.3 Estimating the extent of the hazardous zone . 65
Annex E (informative) Examples of hazardous area classification . 68

– 4 – IEC 60079-10-1:2015 © IEC 2015
E.1 General . 68
E.2 Examples . 68
E.3 Example case study for area classification . 83
Annex F (informative) Schematic approach to classification of hazardous areas . 93
F.1 Schematic approach to classification of hazardous areas . 93
F.2 Schematic approach to classification of hazardous areas . 94
F.3 Schematic approach to classification of hazardous areas . 95
F.4 Schematic approach to classification of hazardous areas . 96
Annex G (informative) Flammable mists . 97
Annex H (informative) Hydrogen . 99
Annex I (informative) Hybrid mixtures . 101
I.1 General . 101
I.2 Use of ventilation . 101
I.3 Concentration limits . 101
I.4 Chemical reactions . 101
I.5 Energy/Temperature limits . 101
I.6 Zoning requirements . 101
Annex J (informative) Useful equations in support to hazardous area classification . 102
J.1 General . 102
J.2 Dilution with air of a flammable substance release . 102
J.3 Estimate of the time required to dilute a flammable substance release . 102
Annex K (informative) Industry codes and national standards . 104
K.1 General . 104
Bibliography . 106

Figure A.1 – Preferred symbols for hazardous area zones . 30
Figure A.2 – Gas/vapour at low pressure (or at high pressure in case of unpredictable
release direction) . 33
Figure A.3 – Gas/vapour at high pressure . 33
Figure A.4 – Liquefied gas . 34
Figure A.5 – Flammable liquid (non boiling evaporative pool) . 34
Figure B.1 – Forms of release . 40
Figure B.2 – Volumetric evaporation rate of liquids . 45
Figure C.1 – Chart for assessing the degree of dilution . 52
Figure C.2 – Self diffusion of an unimpeded high velocity jet release . 57
Figure C.3 – Supply only ventilation . 58
Figure C.4 – Supply and extraction ventilation . 58
Figure C.5 – Local extraction ventilation . 60
Figure C.6 – Volumetric flow rate of fresh air per m of equivalent effective opening
area . 63
Figure C.7 – Example of opposing ventilation driving forces . 64
Figure D.1 – Chart for estimating hazardous area distances . 66
Figure E.1 – Degree of dilution (Example No. 1) . 69
Figure E.2 – Hazardous distance (Example No. 1) . 70
Figure E.3 – Zone classification (Example No. 1) . 70
Figure E.4 – Degree of dilution (Example No. 2) . 72

Figure E.5 – Hazardous distance (Example No. 2) . 73
Figure E.6 – Degree of dilution (Example No. 3) . 75
Figure E.7 – Hazardous distance (Example No. 3) . 76
Figure E.8 – Zones classification (Example No. 3) . 76
Figure E.9 – Degree of dilution (Example No. 4) . 78
Figure E.10 – Hazardous distance (Example No. 4) . 79
Figure E.11 – Zones classification (Example No. 4) . 79
Figure E.12 – Degree of dilution (Example No. 5) . 82
Figure E.13 – Hazardous distance (Example No. 5) . 83
Figure E.14 – Enclosed compressor handling natural gas . 85
Figure E.15 – Example of area classification for a compressor facility handling natural
gas (elevation) . 91
Figure E.16 – Example of area classification for a compressor facility handling natural
gas (plan) . 92
Figure F.1 – Schematic approach to classification . 93
Figure F.2 – Schematic approach to classification for continuous grade releases . 94
Figure F.3 – Schematic approach to classification for primary grade releases . 95
Figure F.4 – Schematic approach to classification for secondary grade releases . 96

Table A.1 − Hazardous area classification data sheet – Part I: Flammable substance
list and characteristics . 31
Table A.2 − Hazardous area classification data sheet − Part II: List of sources of
release . 32
Table B.1 – Suggested hole cross sections for secondary grade of releases . 39
Table B.2 – Effect of hazardous zones on openings as possible sources of release . 47
Table C.1 – Indicative outdoor ventilation velocities (u ) . 52
w
Table D.1 – Zones for grade of release and effectiveness of ventilation . 65
Table E.1 – Compressor facility handling natural gas . 86
Table E.2 – Hazardous area classification data sheet − Part I: Flammable substance
list and characteristics . 88
Table E.3 – Hazardous area classification data sheet − Part II: List of sources of
release (1 of 2) . 89
Table K.1 – Examples of codes and standards . 105

– 6 – IEC 60079-10-1:2015 © IEC 2015
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EXPLOSIVE ATMOSPHERES –
Part 10-1: Classification of areas –
Explosive gas atmospheres
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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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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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
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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 60079-10-1 has been prepared by subcommittee 31J:
Classification of hazardous areas and installation requirements, of IEC technical
committee 31: Equipment for explosive atmospheres.
This bilingual version (2016-01) corresponds to the English version, published in 2015-09.
This second edition of IEC 60079-10-1 cancels and replaces the first edition, published in
2008, and constitutes a technical revision. The significant technical changes with respect to
the previous edition are as follows:

Type
Minor and Major
Changes Clause editorial Extension technical
changes changes
Complete restructuring and dividing into sections to
identify possible methodologies for classifying Main body
X X X
hazardous areas and to provide further explanation of the text
on specific assessment factors
Introducing new terms and the definitions
3 X
Introducing clauses for alternative methods of area
5 X X
classification
Updating examples for presentation of hazardous
area classification Annex A X X
Updating calculations for release rate Annex B X X
Complete re-write with a new approach based upon
the degree of dilution instead of the degree of Annex C X X
ventilation
Introduced as a new Annex for zone extents
Annex D X
Updated with new examples to explain the
Annex E X
methodology set forth in Annexes A, B, C and D
Update of the flow chart illustrating the area
classification procedure by dividing it into four Annex F X
sections
Introduced as a new Annex on hydrogen Annex H X
Introduced as a new Annex on hybrid mixtures
Annex I X
Introduced as a new Annex with supplementary
Annex J X
equations
Introduced as a new Annex for reference to national
and industry codes with specific examples of Annex K X
hazardous area classification
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:
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.
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.
Major technical changes addition of technical requirements
increase of technical requirements

– 8 – IEC 60079-10-1:2015 © IEC 2015
These are changes to technical requirements (addition, increase of the level or removal).
NOTE These changes represent current technological knowledge. However, these changes should not normally
have an influence on equipment already placed on the market.
The text of this standard is based on the following documents:
FDIS Report on voting
31J/253/FDIS 31J/256/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.
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 60079 series, 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 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.
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.
INTRODUCTION
In areas where dangerous quantities and concentrations of flammable gas or vapour may
arise, protective measures need to be applied in order to reduce the risk of explosions. This
part of IEC 60079 sets out the essential criteria against which the ignition hazards can be
assessed, and gives guidance on the design and control parameters which can be used in
order to reduce such hazards.
– 10 – IEC 60079-10-1:2015 © IEC 2015
EXPLOSIVE ATMOSPHERES –
Part 10-1: Classification of areas –
Explosive gas atmospheres
1 Scope
This part of IEC 60079 is concerned with the classification of areas where flammable gas or
vapour hazards may arise and may then be used as a basis to support the proper selection
and installation of equipment for use in hazardous areas.
It is intended to be applied where there may be an ignition hazard due to the presence of
flammable gas or vapour, mixed with air, but it does not apply to:
a) mines susceptible to firedamp;
b) the processing and manufacture of explosives;
c) catastrophic failures or rare malfunctions which are beyond the concept of abnormality
dealt with in this standard (see 3.7.3 and 3.7.4);
d) rooms used for medical purposes;
e) commercial and industrial applications where only low pressure fuel gas is used for
appliances e.g. for cooking, water heating and similar uses, where the installation is
compliant with relevant gas codes;
f) domestic premises;
g) where a hazard may arise due to the presence of combustible dusts or combustible flyings
but the principles may be used in assessment of a hybrid mixture (refer also to
IEC 60079-10-2).
NOTE Additional guidance on hybrid mixtures is provided in Annex I.
Flammable mists may form or be present at the same time as flammable vapour. In such case
the strict application of the details in this standard may not be appropriate. Flammable mists
may also form when liquids not considered to be a hazard due to the high flash point are
released under pressure. In these cases the classifications and details given in this standard
do not apply. Information on flammable mists is provided in Annex G.
For the purpose of this standard, an area is a three-dimensional region or space.
Atmospheric conditions include variations above and below reference levels of 101,3 kPa
(1 013 mbar) and 20 °C (293 K), provided that the variations have a negligible effect on the
explosion properties of the flammable substances.
In any process plant, irrespective of size, there may be numerous sources of ignition apart
from those associated with equipment. Appropriate precautions will be necessary to ensure
safety in this context. This standard is applicable with judgement for other ignition sources.
This standard does not take into account the consequences of ignition of an explosive
atmosphere.
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 60079-14, Explosive atmospheres – Part 14: Electrical installations design, selection and
erection
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
explosive atmosphere
mixture with air, under atmospheric conditions, of flammable substances in the form of gas,
vapour, dust, fibres, or flyings, which, after ignition, permits self-sustaining flame propagation
[SOURCE: IEC 60079-0:2013, 3.30]
3.2
explosive gas atmosphere
mixture with air, under atmospheric conditions, of flammable substances in the form of gas or
vapour, which, after ignition, permits self-sustaining flame propagation
Note 1 to entry: Although a mixture which has a concentration above the upper flammable limit (UFL) is not an
explosive gas atmosphere, it can readily become so and, generally for area classification purposes, it is advisable
to consider it as an explosive gas atmosphere.
Note 2 to entry: There are some gases and vapours which are explosive with the concentration of 100 % (e.g.
acetylene, CAS no. 74-86-2, C H ; monovinyl acetylene, CAS no. 689-97-4, C H ; 1-propyl nitrate (vapour), CAS
2 2 4 4
no. 627-13-4, CH (CH ) NO ; isopropyl nitrate (vapour), CAS no. 1712-64-7, (CH ) CH ONO ; ethylene oxide
3 2 2 3 3 2 2
(vapour), CAS no. 75-21-8, (CH ) O; hydrazine (vapour), CAS no. 302-01-2, H N .
2 2 4 2
[SOURCE: IEC 60079-0:2013, 3.32, modified (addition of Notes to entry)]
3.3
hazardous areas and zones
3.3.1
hazardous area (on account of explosive gas atmospheres)
an area in which an explosive gas atmosphere is or may be expected to be present, in
quantities such as to require special precautions for the construction, installation and use of
equipment
Note 1 to entry: The interior of many items of process equipment are commonly considered as a hazardous area
even though a flammable atmosphere may not normally be present to account for the possibility of air entering the
equipment. Where specific controls such as inerting are used the interior of process equipment may not need to be
classified as a hazardous area.
3.3.2
non-hazardous area (on account of explosive gas atmospheres)
an area in which an explosive gas atmosphere is not expected to be present in quantities
such as to require special precautions for the construction, installation and use of equipment
3.3.3
zones
hazardous area classification based upon the frequency of the occurrence and duration of an
explosive atmosphere
– 12 – IEC 60079-10-1:2015 © IEC 2015
3.3.4
zone 0
an area in which an explosive gas atmosphere is present continuously or for long periods or
frequently
Note 1 to entry: Both “long” and “frequently” are the terms which are intended to describe a very high likelihood of
a potentially explosive atmosphere in the area. In that respect, those terms do not necessarily need to be
quantified.
3.3.5
zone 1
an area in which an explosive gas atmosphere is likely to occur periodically or occasionally in
normal operation
3.3.6
zone 2
an area in which an explosive gas atmosphere is not likely to occur in normal operation but, if
it does occur, it will exist for a short period only
Note 1 to entry: Indications of the frequency of the occurrence and duration may be taken from codes relating to
specific industries or applications.
[SOURCE: IEC 60050-426:2009, 426-03-05]
3.3.7
extent of zone
distance in any direction from the source of release to where a gas/air mixture will be diluted
by air to a concentration below the lower flammable limit
3.4
releases
3.4.1
source of release
a point or location from which a flammable gas, vapour, mist or liquid may be released into
the atmosphere so that an explosive gas atmosphere could be formed
[SOURCE: IEC 60050-426:2009, 426-03-06, modified (addition of "mist")]
3.4.2
continuous grade of release
release which is continuous or is expected to occur frequently or for long periods
Note 1 to entry: Both “frequently” and “long” are the terms which are intended to describe a very high likelihood of
a potential release. In that respect, those terms do not necessarily need to be quantified.
3.4.3
primary grade of release
release which can be expected to occur periodically or occasionally during normal operation
3.4.4
secondary grade of release
release which is not expected to occur in normal operation and, if it does occur, is likely to do
so only infrequently and for short periods
3.4.5
release rate
quantity of flammable gas, liquid, vapour or mist emitted per unit time from the source of
release
3.5
ventilation and dilution
3.5.1
ventilation
movement of air and its replacement with fresh air due to the effects of wind, temperature
gradients, or artificial means (for example, fans or extractors)
3.5.2
dilution
the mixing of flammable vapour or gas with air which, over time, will reduce the flammable
concentration
3.5.3
dilution volume
the volume in the vicinity of a source of release where the concentration of flammable gas or
vapour is not diluted to a safe level
Note 1 to entry: In certain instances, the volumes under 3.5.3 and 3.5.5 could be the same.
3.5.4
background concentration
the mean concentration of flammable substance within the volume under consideration
outside of the release plume or jet
3.5.5
volume under consideration
the volume served by the ventilation in the vicinity of the release being considered
Note 1 to entry: For an enclosed space this could be an entire room or part of a larger space where the
considered ventilation will dilute the gas or vapour from a given source of release. Outdoors, this is the volume
around a source of release where an explosive mixture could form. In congested outdoor places this volume could
be dictated by the partial enclosure provided by the surrounding objects.
3.6
properties of flammable substance
3.6.1
flammable substance
substance which is itself flammable, or is capable of producing a flammable gas, vapour or
mist
3.6.2
flammable liquid
liquid capable of producing a flammable vapour under any foreseeable operating conditions
Note 1 to entry: An example of a foreseeable operating condition is one in which the flammable liquid is handled
at temperatures close to or above its flash point.
Note 2 to entry: This definition is used
...

SLOVENSKI STANDARD
01-februar-2000
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6WLNDOQHLQNUPLOQHQDSUDYH
Electrical installation guide - Part 53: Selection and erection of electrical equipment -
Switchgear and controlgear
Guide pour les installations électriques - Partie 53: Choix et mise en oeuvre des
matériels électriques - Appareillage
Ta slovenski standard je istoveten z: IEC/TS 61200-53
ICS:
29.130.01 Stikalne in krmilne naprave Switchgear and controlgear
na splošno in general
91.140.50 Sistemi za oskrbo z elektriko Electricity supply systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

RAPPORT CEI
TECHNIQUE IEC
1200-53
TECHNICAL
Première édition
REPORT
First edition
1994-10
Guide pour les installations électriques —
Partie 53:
Choix et mise en oeuvre des matériels électriques -
Appareillage
Electrical installation guide —
Part 53:
Selection and erection of electrical equipment —
Switchgear and controlgear
Numéro de référence
IEC
Reference number
•
CEI/IEC 1200-53: 1994
Numéros des publications Numbering
CEI As from 1 January 1997 all IEC publications are
Depuis le 1er janvier 1997, les publications de la
sont numérotées à partir de 60000. issued with a designation in the 60000 series.
Consolidated publications
Publications consolidées
Les versions consolidées de certaines publications de Consolidated versions of some IEC publications
including amendments are available. For example,
la CEI incorporant les amendements sont disponibles.
Par exemple, les numéros d'édition 1.0, 1.1 et 1.2 edition numbers 1.0, 1.1 and 1.2 refer, respectively, to
indiquent respectivement la publication de base, la the base publication, the base publication incor-
porating amendment 1 and the base publication
publication de base incorporant l'amendement 1, et
incorporating amendments 1 and 2.
la publication de base incorporant les amendements 1
et 2.
Validité publication Validity of this publication
de la présente
Le contenu technique des publications de la CEI est The technical content of IEC publications is kept under
constamment revu par la CEI afin qu'il reflète l'état constant review by the IEC, thus ensuring that the
content reflects current technology.
actuel de la technique.
Information relating to the date of the reconfirmation of
Des renseignements relatifs à la date de re-
confirmation de la publication sont disponibles dans the publication is available in the IEC catalogue.
le Catalogue de la CEI.
Information on the subjects under consideration and
Les renseignements relatifs à des questions à l'étude et
work in progress undertaken by the technical com-
des travaux en cours entrepris par le comité technique
qui a établi cette publication, ainsi que la liste des mittee which has prepared this publication, as well as
the list of publications issued, is to be found at the
publications établies, se trouvent dans les documents
following IEC sources:
ci-dessous:
• IEC web site*
• «Site web» de la CEI*
• Catalogue of IEC publications
• Catalogue des publications de la CEI
Published yearly with regular updates
Publié annuellement et mis à jour régulièrement
(Catalogue en ligne)* (On-line catalogue)*
• Bulletin de la CEI • IEC Bulletin
Disponible à la fois au «site web» de la CEI* Available both at the IEC web site* and
as a printed periodical
et comme périodique imprimé
Terminologie, symboles graphiques Terminology, graphical and letter
et littéraux symbols
For general terminology, readers are referred to
En ce qui concerne la terminologie générale, le lecteur
se reportera à la CEI 60050: Vocabulaire Electro- IEC 60050: International Electrotechnical Vocabulary
(VEI). (IEV).
technique International
For graphical symbols, and letter symbols and signs
Pour les symboles graphiques, les symboles littéraux
approved by the IEC for general use, readers are
et les signes d'usage général approuvés par la CEI, le
Symboles littéraux à referred to publications IEC 60027: Letter symbols to
lecteur consultera la CEI 60027:
Symboles be used in electrical technology, IEC 60417: Graphical
utiliser en électrotechnique, la CEI 60417:
graphiques utilisables sur le matériel. Index, relevé et symbols for use on equipment. Index, survey and
compilation des feuilles individuelles, et la CEI 60617: compilation of the single sheets and IEC 60617:
Graphical symbols for diagrams.
Symboles graphiques pour schémas.

la page de titre. * See web site address on title page.
* Voir adresse «site web» sur
RAPPORT CEI
TECHNIQUE - TYPE 2 I EC
1200-53
TECHNICAL
Première
édition
REPORT - TYPE 2
First edition
1994-10
électriques —
Guide pour les installations
Partie 53:
Choix et mise en oeuvre des matériels électriques —
Appareillage
Electrical installation guide —
Part 53:
Selection and erection of electrical equipment —
Switchgear and controlgear
réservés — Copyright - all rights reserved
© CEI 1994 Droits de reproduction
No part of this publication may be reproduced or utilized in
Aucune partie de cette publication ne peut être reproduite ni
any form or by any means, electronic or mechanical,
utilisée sous quelque forme que ce soit et par aucun pro-
including photocopying and microfilm, without permission
cédé, électronique ou mécanique, y compris la photocopie et
in writing from the publisher.
les microfilms, sans l'accord écrit de l'éditeur.
Genève, Suisse
Bureau Central de la Commission Electrotechnique Internationale 3, rue de Varembé
CODE PRIX
Commission Electrotechnique Internationale
International Electrotechnical Commission J
PRICE CODE
IEC McNgiyuapoQHae 3nelcrpoTe%HH4ecna i HoMHCCHa
voir catalogue en vigueur
Pour prix, ^
•
For price, see current catalogue

IEC Publication 1200-53
Publication 1200-53 de la CEI
(First edition - 1994)
(Première édition - 1994)
installations électriques – Electrical installation guide –
Guide pour les
Partie 53:
Part 53:
Choix et mise en oeuvre des matériels électriques –
Selection and erection of electrical equipment –
Appareillage
Switchgear and controlgear
C O R R I G E N D U M 1
Page 5
Page 4
In the second column of the table, indicating
Dans la deuxième colonne du tableau,
the report on voting, add the following:
indiquant le rapport de vote, ajouter ce qui
suit:
64(SEC)677B
64(SEC)677B
Page 7
Page 6
Under the title, before subclause 53. 1, add
Sous le titre, avant le paragraphe 53. 1,
the following introductory lines:
ajouter les lignes d’introduction suivantes:
In the informative annexes A and B,
Dans les annexes informatives A et B, des
information is given, respectively, on the
informations sont données, respectivement
choice of the utilisation categories of low-
sur le choix des catégories d’emploi des
voltage switchgear and controlgear and on
appareillages à basse tension et sur les
the methods of installation of electrical
méthodes d’ins-tallation des accessoires
accessories for household and similar
électriques pour usages domestiques et
analogues. applications.
Page 17
Page 16
After figure 4, add the following annexes A
Après la figure 4, ajouter les annexes A et B
and B:
suivantes:
(see overleaf)
(voir au verso)
− 2 −
Annexe A
(informative)
Exemples de catégories d’emploi pour l’appareillage à
basse tension
(voir annexe B de la CEI 947-1)
Norme CEI
Nature du
Catégorie Applications caractéristiques de matériel
courant
correspondante
(voir article 1)
Alternatif AC-1 Charges non inductives ou faiblement inductives, fours à résistances
AC-2 Moteurs à bagues: démarrage, coupure
Moteurs à cage: démarrage, coupure des moteurs lancés
AC-3
AC-4 Moteurs à cage: démarrage, inversion de marche 1 ), marche par
2)
à-coups
Commande de lampes à décharge
AC-5a
AC-5b Commande de lampes à incandescence 947-1
AC-6a Commande de transformateurs
AC-6b Commande de batteries de condensateurs
AC-7a Charges faiblement inductives pour appareils domestiques et appli-
cations similaires
AC-7b Moteurs pour applications domestiques
AC-8a Commande de moteurs de compresseurs hermétiques de réfrigéra-
tion avec réarmement manuel des déclencheurs de surcharge
AC-8b Commande de moteurs de compresseurs hermétiques de réfrigéra-
tion avec réarmement automatique des déclencheurs de surcharge
AC-12 Commande de charges ohmiques et de charges statiques isolées par
photo-coupleur
AC-13 Commande de charges statiques isolées par transformateur 947-5
AC-14 Commande de faibles charges électromagnétiques d’électro-aimants
Commande de charges électromagnétiques d’électro-aimants
AC-15
AC-20 Fermeture et ouverture à vide
AC-21 Charges ohmiques, y compris surcharges modérées
AC-22
Charges mixtes ohmiques et inductives, y compris surcharges
modérées 947-3
AC-23 Charges constituées par des moteurs ou autres charges fortement
inductives
Alternatif A
Protection des circuits sans courant assigné de courte durée
et admissible
947-2
continu B Protection des circuits avec courant assigné de courte durée
admissible
Charges non inductives ou faiblement inductives, fours à résistances
Continu DC-1
DC-3 Moteurs shunts, démarrage, inversion de marche 1 ), marche par
2)
947-4
à-coups
, coupure dynamique de moteurs
DC-5 Moteurs série, démarrage, inversion de marche 1 ), marche par
à-coups 2), coupure dynamique de moteurs
DC-6 Commande de lampes à incandescence
DC-12 Commande de charges ohmiques et de charges statiques isolées par
photo-coupleurs
DC-13 Commande d’électro-aimants à courant continu 947-5
DC-14 Commande d’électro-aimants à courant continu ayant des résis-
tances d’économie
DC-20 Fermeture et ouverture à vide
DC-21 Charges résistives, y compris surcharges modérées
DC-22 Charges mixtes résistives et inductives, y compris surcharges 947-3
modérées (par exemple: moteurs shunt)
DC-23 Charges fortement inductives (par exemple: moteurs série)
1)
Par inversion de marche, on entend l’arrêt ou l’inversion rapide du sens de rotation du moteur en permutant
des connexions d’alimentation du moteur pendant que celui-ci tourne.
2)
Par marche par à-coups, on entend une commande caractérisée par une ou plusieurs fermetures brèves et
fréquentes du circuit d’un moteur, afin d’obtenir de petits déplacements de l’organe entraîné.

− 3 −
Annex A
(informative)
Examples of utilization categories for low-voltage
switchgear and controlgear
(see annex B of IEC 947-1)
Relevant IEC
Nature of
Category Typical applications product
current
standard
(see clause 1)
Non-inductive or slightly inductive loads, resistance furnaces
AC AC-1
Slip-ring motors: starting, switching off
AC-2
Squirrel-cage motors: starting, switching off motors during running
AC-3
1 2)
AC-4 Squirrel-cage motors: starting, plugging ), inching
AC-5a Switching of electic discharge lamp control
AC-5b Switching of incandescent lamps 947-1
AC-6a Switching of transformers
AC-6b Switching of capacitor banks
AC-7a Slightly inductive loads in household appliances and similar
applications
AC-7b Motor-loads for household applications
AC-8a Hermetic refrigerant compressor motor control with manual resetting
of overload releases
AC-8b Hermetic refrigerant compressor motor control with automatic
resetting of overload releases
AC-12 Control of resistive loads and solid state loads with isolation by
optocouplers
AC-13 Control of solid state loads with transformer isolation 947-5
AC-14 Control of small electromagnetic loads
AC-15 Control of a.c. electromagnetic loads
AC-20 Connecting and disconnecting under no-load conditions
AC-21 Switching of resistive loads, including moderate overloads
AC-22 Switching of mixed resistive and inductive loads, including moderate
overloads 947-3
AC-23 Switching of motor loads or other highly inductive loads
AC A Protection of circuits, with no rated short-time withstand current
947-2
and DC B Protection of circuits, with a rated short-time withstand current
DC DC-1 Non-inductive or slightly inductive loads, resistance furnaces
DC-3 1 ), inching 2), dynamic breaking of
Shunt-motors, starting, plugging
947-4
motors
DC-5 Series-motors, starting, plugging 1 ), inching 2), dynamic breaking of
motors
DC-6 Switching of incandescent lamps
DC-12 Control of resistive loads and solid state loads with isolation by
optocouplers
DC-13 Control of d.c. electromagnets 947-5
DC-14 Control of d.c. electromagnetic loads having economy resistors in
circuit
DC-20 Connecting and disconnecting under non-load conditions
DC-21 Switching of resistive loads, including moderate overloads
DC-22 Switching of mixed resistive and inductive loads, including moderate 947-3
overloads (e.g. shunt motors)
DC-23 Switching of highly inductive loads (e.g. series motors)
1)
By plugging is understood stopping or reversing the motor rapidly by reversing motor primary connections
while the motor is running.
2)
By inching (jogging) is understood energizing a motor once or repeatedly for short periods to obtain small
movements of the driven mechanism.

− 4 −
Annexe B
(informative)
Méthodes d’installation des électriques
appareillages
(voir CEI 669-1 et 884-1)
Selon leur méthode d’installation, les appareillages électriques sont classifiés (voir paragraphe
7.1.7 de la CEI 669-1, sur les interrupteurs et le paragraphe 7.2.3 de la CEI 884-1, sur les
prises de courant pour les installations domestiques et analogues, comme suit:
− appareillages de conception A, si le capot ou une plaque de couverture ou des parties de
ces derniers peuvent être retirés sans déplacement des conducteurs;
− appareillages de conception B, si le capot ou une plaque de couverture ou des parties de
ces derniers ne peuvent être retirés sans déplacement des conducteurs;
NOTE − Si un appareil fixe possède un socle (partie principale) ne pouvant être séparé du couvercle ou de
la plaque de couverture, et qui nécessite une plaque supplémentaire pouvant être retirée pour des travaux
de décoration murale sans déplacement des conducteurs, alors cet appareillage est considéré comme étant
de conception A, à condition que la plaque supplémentaire satisfasse aux prescriptions spécifiées pour les
couvercles et les plaques de couverture.
Les appareillages de type A et B sont considérés comme sûrs s’ils sont correctement installés
et utilisés.
− 5 −
Annex B
(informative)
Methods of installation of electrical accessories
(see IEC 669-1 and 884-1)
According to their method of installation, fixed accessories are classified (see subclause 7.1.7
of IEC 669-1, concerning switches, and subclause 7.2.3 of IEC 884-1, concerning socket-
outlets, for household and similar applications) as follows:
− accessories of design A, where the cover or cover-plate or parts of them can be removed
without displacement of the conductors;
− accessories of design B, where the cover or cover-plate or parts of them cannot be
removed without displacement of the conductors.
NOTE − If a fixed accessory has a base (main part) which cannot be separated from the cover or cover-
plate, and requires a supplementary plate which can be removed for redecorating the wall without
displacement of the conductors, it is considered to be of design A, provided the supplementary plate meets
the requirements specified for covers and cover-plates.
Both accessories of design A and of design B are considered to be adequately safe when
correctly installed and used.
Octobre 1995 October 1995
– 2 – 1200-53 ©CEI:1994
COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE
GUIDE POUR LES INSTALLATIONS ÉLECTRIQUES —
Partie 53: Choix et mise en oeuvre des matériels électriques —
Appareillage
AVANT-PROPOS
1) La CEI (Commission Electrotechnique Internationale) est une organisation mondiale de normalisation
composée de l'ensemble des comités électrotechniques nationaux (Comités nationaux de la CEI). La CEI a
pour objet de favoriser la coopération internationale pour toutes les questions de normalisation dans les
domaines de l'électricité et de l'électronique. A cet effet, la CEI, entre autres activités, publie des Normes
internationales. Leur élaboration est confiée à des comités d'études, aux travaux desquels tout Comité
national intéressé par le sujet traité peut participer. Les organisations internationales, gouvernementales et
non gouvernementales, en liaison avec la CEI, participent également aux travaux. La CEI collabore
étroitement avec l'Organisation Internationale de Normalisation (ISO), selon des conditions fixées par
accord entre les deux organisations.
Les décisions ou accords officiels de la CEI en ce qui concerne les questions techniques, préparés par les
2)
comités d'études où sont représentés tous les Comités nationaux s'intéressant à ces questions, expriment
dans la plus grande mesure possible un accord international sur les sujets examinés.
3) Ces décisions constituent des recommandations internationales publiées sous forme de normes, de
rapports techniques ou de guides et agréées comme telles par les Comités nationaux.
4) Dans le but d'encourager l'unification internationale, les Comités nationaux de la CEI s'engagent
appliquer de façon transparente, dans toute la mesure possible, les Normes internationales de la CEI
à
dans leurs normes nationales et régionales. Toute divergence entre la norme de la CEI et la norme
nationale ou régionale correspondante doit être indiquée en termes clairs dans cette dernière.
La tâche principale des comités d'études de la CEI est d'élaborer des Normes
internationales. Exceptionnellement, un comité d'études peut proposer la publication d'un
rapport technique de l'un des types suivants:
type 1, lorsque, en dépit de maints efforts, l'accord requis ne peut être réalisé en
•
faveur de la publication d'une Norme internationale;
type 2, lorsque le sujet en question est encore en cours de développement
•
technique ou lorsque, pour une raison quelconque, la possibilité d'un accord pour la
publication d'une Norme internationale peut être envisagée pour l'avenir mais pas dans
l'immédiat;
• type 3, lorsqu'un comité d'études a réuni des données de nature différente de
celles qui sont normalement publiées comme Normes internationales, cela pouvant
comprendre, par exemple, des informations sur l'état de la technique.
Les rapports techniques des types 1 et 2 font l'objet d'un nouvel examen trois ans au plus
tard après leur publication afin de décider éventuellement de leur transformation en
Normes internationales. Les rapports techniques de type 3 ne doivent pas nécessairement
être révisés avant que les données qu'ils contiennent ne soient plus jugées valables ou
utiles.
technique de type 2, a par le comité d'études 64 de
La CEI 1200-53, rappo rt été établie
la CEI: Installations électriques des bâtiments.

1200-53 © - 3 -
IEC:1994
INTERNATIONAL ELECTROTECHNICAL COMMISSION
ELECTRICAL INSTALLATION GUIDE —
Part 53: Selection and erection of electrical equipment —
Switchgear and controlgear
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization
comprising all national electrotechnical committees (IEC National Committees). The object of the IEC is to
promote international cooperation on all questions concerning standardization in the electrical and
electronic fields. To this end and in addition to other activities, the IEC publishes International Standards.
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. The 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 the IEC on technical matters, prepared by technical committees on
which all the National Committees having a special interest therein are represented, express, as nearly as
possible, an international consensus of opinion on the subjects dealt with.
3) They have the form of recommendations for international use published in the form of standards, technical
reports or guides and they are accepted by the National Committees in that sense.
In order to promote international unification, IEC National Committees undertake to apply IEC International
4)
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
The main task of IEC technical committees is to prepare International Standards. In excep-
tional circumstances, a technical committee may propose the publication of a technical
of one of the following types:
repo rt
cannot be obtained for the publication of an Inter-
• type 1, when the required suppo rt
rts;
national Standard, despite repeated effo
type 2, when the subject is still under technical development or where for any other
•
reason there is the future but not immediate possibility of an agreement on an Inter-
national Standard;
• type 3, when a technical committee has collected data of a different kind from that
which is normally published as an International Standard, for example "state of the a rt".
s of types 1 and 2 are subject to review within three years of publication to
Technical repo rt
decide whether they can be transformed into International Standards. Technical reports of
type 3 do not necessarily have to be reviewed until the data they provide are considered
to be no longer valid or useful.
of type 2, has been prepared by IEC technical
IEC 1200-53, which is a technical repo rt
committee 64: Electrical installations of buildings.

– 4 – 1200-53 ©CEI:1994
complément à la CEI 364-5-53 pour le choix
Le présent guide donne des indications en
courts-circuits
des de protection destinés à protéger les canalisations contre les
dispositifs
de protection.
concernant la sélectivité relative entre dispositifs
et donne des explications
du présent guide correspondent à ceux de la CEI 364-5-53.
Les numéros des paragraphes
rapport technique est issu des documents suivants:
Le texte de ce
de comité Rapport de vote
Projet
64(SEC)677A
64(SEC)630A
donne toute information sur le vote
Le rapport de vote indiqué dans le tableau ci-dessus
ce rapport technique.
ayant abouti à l'approbation de
Le présent document est publié dans la série des rapports techniques de
type 2 (conformément au paragraphe G.4.2.2 de la partie 1 des Directives
CEI/ISO) comme 'norme prospective d'application provisoire' dans le
domaine des systèmes d'isolation car il est urgent d'avoir des indications
sur la meilleure façon d'utiliser les normes dans ce domaine afin de
répondre à un besoin déterminé.
Ce document ne doit pas être considéré comme une 'Norme
internationale». Il est proposé pour une mise en oeuvre provisoire, dans
le but de recueillir des informations et d'acquérir de l'expérience quant à
son application dans la pratique. Il est de règle d'envoyer les observations
éventuelles relatives au contenu de ce document au Bureau Central de
la CEI.
Il sera procédé à un nouvel examen de ce rapport technique de type 2
trois ans au plus tard après sa publication, avec la faculté d'en prolonger
la validité pendant trois autres années, de le transformer en Norme
internationale ou de l'annuler.

1200-53 © IEC:1994 - 5 -
This guide gives additional information to the requirements according to IEC 364-5-53 for
the selection of protective devices to protect wiring systems against short-circuit currents
and explains how protective devices are to be selected in order to achieve discrimination.
The subclause numbers used herein are in line with subclauses in IEC 364-5-53.
The text of this technical report is based on the following documents:
Committee draft Report on voting
64(SEC)630
64(SEC)677A
64(SEC)630A
Full information on the voting for the approval of this technical report can be found in the
repo rt on voting indicated in the above table.
document is issued in the type 2 technical report series o
...