SIST EN IEC 60079-10-1:2021
(Main)Explosive atmospheres - Part 10-1: Classification of areas - Explosive gas atmospheres (IEC 60079-10-1:2020)
Explosive atmospheres - Part 10-1: Classification of areas - Explosive gas atmospheres (IEC 60079-10-1:2020)
IEC 60079-10-1:2020 is concerned with the classification of areas where flammable gas or vapour hazards may arise and may then be used as a basis to support the proper design, construction, operation and maintenance of equipment for use in hazardous areas.
It is intended to be applied where there may be an ignition hazard due to the presence of flammable gas or vapour, mixed with air, but it does not apply to:
a) mines susceptible to firedamp;
b) the processing and manufacture of explosives;
c) catastrophic failures or rare malfunctions which are beyond the concept of normality dealt with in this standard;
d) rooms used for medical purposes;
e) domestic premises;
f) where a hazard may arise due to the presence of combustible dusts or combustible flyings but the principles may be used in assessment of a hybrid mixture.
Flammable mists may form or be present at the same time as flammable vapour. In such case the strict application of the details in this document may not be appropriate. Flammable mists may also form when liquids not considered to be a hazard due to the high flash point are released under pressure. In these cases the classifications and details given in this document do not apply.
For the purpose of this document, an area is a three-dimensional region or space.
Atmospheric conditions include variations above and below reference levels of 101,3 kPa (1 013 mbar) and 20 °C (293 K), provided that the variations have a negligible effect on the explosion properties of the flammable substances.
In any site, irrespective of size, there may be numerous sources of ignition apart from those associated with equipment. Appropriate precautions will be necessary to ensure safety in this context. This standard is applicable with judgement for other ignition sources but in some applications other safeguards may also need to be considered. E.g. larger distances may apply for naked flames when considering hot work permits.
This document does not take into account the consequences of ignition of an explosive atmosphere except where a zone is so small that if ignition did occur it would have negligible consequences.
This third edition of IEC 60079-10-1 cancels and replaces the second edition, published in 2015, and constitutes a technical revision, see foreword for further details.
Explosionsgefährdete Bereiche - Teil 10-1: Einteilung der Bereiche - Gasexplosionsgefährdete Bereiche (IEC 60079-10-1:2020)
Atmosphères explosives - Partie 10-1: Classement des emplacements - Atmosphères explosives gazeuses (IEC 60079-10-1:2020)
Elle est destinée à être appliquée là où il peut exister un danger d'inflammation du fait de la présence de gaz ou vapeurs inflammables, en mélange avec l'air, mais elle ne s'applique pas:
a) aux mines grisouteuses;
b) au traitement et à la fabrication des explosifs;
c) aux défaillances catastrophiques ou rares dysfonctionnements, qui dépassent le concept de normalité traité dans la présente norme;
d) aux locaux utilisés à des fins médicales;
e) aux locaux à usage domestique;
f) lorsqu’un danger peut apparaître compte tenu de la présence de poussières combustibles ou de particules combustibles en suspension dans l'air, mais les principes définis peuvent toutefois être appliqués dans l’évaluation d’un mélange hybride.
Pour les besoins du présent document, un emplacement est une région ou un espace tridimensionnel.
Les conditions atmosphériques englobent les écarts au-dessus et au-dessous des niveaux de référence de 101,3 kPa (1 013 mbar) et 20 °C (293 K) à condition que cela ait un effet négligeable sur les propriétés explosives des substances inflammables.
Dans tout site quelle que soit son importance, il peut y avoir de nombreuses sources d'inflammation en dehors de celles qui sont associées au matériel. Il est nécessaire dès lors de prendre les précautions appropriées pour garantir la sécurité. La présente norme est applicable avec prudence pour ces autres sources d'inflammation mais d'autres applications peuvent nécessiter de prendre en considération d’autres mesures de protection. Par exemple, de plus grandes distances peuvent s'appliquer aux flammes nues lorsqu’il s’agit de permis de travaux à chaud.
Le présent document ne tient pas compte des conséquences de l'inflammation d'une atmosphère explosive, sauf dans une zone si petite que si une inflammation se produit, ses conséquences sont négligeables.
Cette troisième édition de l'IEC 60079-10-1 annule et remplace la deuxième édition parue en 2015. Cette édition constitue une révision technique.
Eksplozivne atmosfere - 10-1. del: Razvrstitev prostorov - Eksplozivne plinske atmosfere (IEC 60079-10-1:2020)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN IEC 60079-10-1:2021
01-april-2021
Nadomešča:
SIST EN 60079-10-1:2016
Eksplozivne atmosfere - 10-1. del: Razvrstitev prostorov - Eksplozivne plinske
atmosfere (IEC 60079-10-1:2020)
Explosive atmospheres - Part 10-1: Classification of areas - Explosive gas atmospheres
(IEC 60079-10-1:2020)
Explosionsgefährdete Bereiche - Teil 10-1: Einteilung der Bereiche -
Gasexplosionsgefährdete Bereiche (IEC 60079-10-1:2020)
Atmosphères explosives - Partie 10-1: Classement des emplacements - Atmosphères
explosives gazeuses (IEC 60079-10-1:2020)
Ta slovenski standard je istoveten z: EN IEC 60079-10-1:2021
ICS:
29.260.20 Električni aparati za Electrical apparatus for
eksplozivna ozračja explosive atmospheres
SIST EN IEC 60079-10-1:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN IEC 60079-10-1:2021
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SIST EN IEC 60079-10-1:2021
EUROPEAN STANDARD EN IEC 60079-10-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2021
ICS 29.260.20 Supersedes EN 60079-10-1:2015 and all of its
amendments and corrigenda (if any)
English Version
Explosive atmospheres - Part 10-1: Classification of areas -
Explosive gas atmospheres
(IEC 60079-10-1:2020)
Atmosphères explosives - Partie 10-1: Classification des Explosionsgefährdete Bereiche - Teil 10-1: Einteilung der
emplacements - Atmosphères explosives gazeuses Bereiche - Gasexplosionsgefährdete Bereiche
(IEC 60079-10-1:2020) (IEC 60079-10-1:2020)
This European Standard was approved by CENELEC on 2021-01-22. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60079-10-1:2021 E
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SIST EN IEC 60079-10-1:2021
EN IEC 60079-10-1:2021 (E)
European foreword
The text of document 31J/307/FDIS, future edition 3 of IEC 60079-10-1, prepared by SC 31J
"Classification of hazardous areas and installation requirements" of IEC/TC 31 "Equipment for
explosive atmospheres" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN IEC 60079-10-1:2021.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2021-10-22
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2024-01-22
document have to be withdrawn
This document supersedes EN 60079-10-1:2015 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Endorsement notice
The text of the International Standard IEC 60079-10-1:2020 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards
indicated:
IEC 60079-0 NOTE Harmonized as EN IEC 60079-0
IEC 60079-14 NOTE Harmonized as EN 60079-14
IEC 60079-13 NOTE Harmonized as EN 60079-13
IEC 60079-10-2 NOTE Harmonized as EN 60079-10-2
IEC 61285 NOTE Harmonized as EN 61285
IEC 61511-1:2016 NOTE Harmonized as EN 61511-1:2017 (not modified)
ISO/IEC 80079-20-1 NOTE Harmonized as EN ISO/IEC 80079-20-1
2
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SIST EN IEC 60079-10-1:2021
IEC 60079-10-1
®
Edition 3.0 2020-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Explosive atmospheres –
Part 10-1: Classification of areas – Explosive gas atmospheres
Atmosphères explosives –
Partie 10-1: Classification des emplacements – Atmosphères explosives
gazeuses
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.260.20 ISBN 978-2-8322-8890-0
Warning! Make sure that you obtained this publication from an authorized distributor.
Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
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SIST EN IEC 60079-10-1:2021
– 2 – IEC 60079-10-1:2020 © IEC 2020
CONTENTS
FOREWORD . 6
INTRODUCTION . 10
1 Scope . 11
2 Normative references . 11
3 Terms and definitions . 12
4 General . 16
4.1 Safety principles . 16
4.2 Hazardous area classification objectives . 17
4.3 Interior of equipment containing flammable materials . 18
4.4 Explosion risk assessment . 18
4.4.1 General . 18
4.4.2 Zone of negligible extent. 18
4.5 Catastrophic failures . 19
4.6 Competence of personnel . 19
5 Hazardous area classification methodology . 19
5.1 General . 19
5.2 Classification by sources of release method . 20
5.3 Use of industry codes and national standards . 21
5.3.1 General . 21
5.3.2 Fuel gas installations . 21
5.4 Simplified methods. 21
5.5 Combination of methods . 21
6 Release of flammable substance . 22
6.1 General . 22
6.2 Sources of release . 22
6.3 Forms of release . 23
6.3.1 General . 23
6.3.2 Gaseous release . 24
6.3.3 Liquefied under pressure release . 24
6.3.4 Liquefied by refrigeration release . 24
6.3.5 Flammable mists release . 25
6.3.6 Vapours release . 25
6.3.7 Liquid release . 25
7 Ventilation (or air movement) and dilution . 26
7.1 General . 26
7.2 Main types of ventilation . 27
7.2.1 General . 27
7.2.2 Natural ventilation . 27
7.2.3 Artificial ventilation . 27
7.2.4 Degree of dilution . 29
8 Type of zone . 30
8.1 General . 30
8.2 Influence of grade of the source of release . 30
8.3 Influence of dilution . 30
8.4 Influence of availability of ventilation . 30
9 Extent of zone . 31
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SIST EN IEC 60079-10-1:2021
IEC 60079-10-1:2020 © IEC 2020 – 3 –
10 Documentation . 31
10.1 General . 31
10.2 Drawings, data sheets and tables . 32
Annex A (informative) Suggested presentation of hazardous areas . 33
A.1 Hazardous area – Preferred symbols for zones . 33
A.2 Hazardous area suggested shapes . 36
Annex B (informative) Estimation of sources of release . 38
B.1 Symbols . 38
B.2 Examples of grade of release . 38
B.2.1 General . 38
B.2.2 Sources giving a continuous grade of release . 39
B.2.3 Sources giving a primary grade of release . 39
B.2.4 Sources giving a secondary grade of release . 39
B.3 Assessment of grades of release . 39
B.4 Summation of releases . 40
B.5 Hole size and source radius . 41
B.6 Forms of release . 43
B.7 Release rate . 44
B.7.1 General . 44
B.7.2 Estimation of release rate . 45
B.7.3 Release rate of evaporative pools . 47
B.8 Release from openings in buildings . 49
B.8.1 General . 49
B.8.2 Openings as possible sources of release . 50
B.8.3 Openings classification . 50
Annex C (informative) Ventilation guidance . 52
C.1 Symbols . 52
C.2 General . 53
C.3 Assessment of ventilation and dilution and its influence on hazardous area . 53
C.3.1 General . 53
C.3.2 Effectiveness of ventilation . 54
C.3.3 Criteria for dilution . 54
C.3.4 Assessment of ventilation velocity . 55
C.3.5 Assessment of the degree of dilution . 56
C.3.6 Dilution in a room . 58
C.3.7 Criteria for availability of ventilation . 59
C.4 Examples of ventilation arrangements and assessments . 60
C.4.1 Introduction . 60
C.4.2 Jet release in a large building . 61
C.4.3 Jet release in a small naturally ventilated building . 62
C.4.4 Jet release in a small artificially ventilated building . 62
C.4.5 Release with low velocity . 63
C.4.6 Fugitive emissions . 63
C.4.7 Local ventilation-extraction . 64
C.5 Natural Ventilation in buildings . 64
C.5.1 General . 64
C.5.2 Wind induced ventilation . 64
C.5.3 Buoyancy induced ventilation . 65
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SIST EN IEC 60079-10-1:2021
– 4 – IEC 60079-10-1:2020 © IEC 2020
C.5.4 Combination of the natural ventilation induced by wind and buoyancy . 67
Annex D (informative) Estimation of hazardous areas . 69
D.1 General . 69
D.2 Estimating types of the zones . 69
D.3 Estimating the extent of the hazardous area . 70
Annex E (informative) Examples of hazardous area classification . 72
E.1 General . 72
E.2 Examples . 72
E.3 Example case study for hazardous area classification . 86
Annex F (informative) Schematic approach to classification of hazardous areas . 96
F.1 Schematic approach to classification of hazardous areas . 96
F.2 Schematic approach to classification of hazardous areas . 97
F.3 Schematic approach to classification of hazardous areas . 98
F.4 Schematic approach to classification of hazardous areas . 99
Annex G (informative) Flammable mists . 100
Annex H (informative) Hydrogen . 103
Annex I (informative) Hybrid mixtures . 105
I.1 General . 105
I.2 Use of ventilation . 105
I.3 Concentration limits . 105
I.4 Chemical reactions . 105
I.5 Energy/temperature limits . 105
I.6 Zoning requirements . 105
Annex J (informative) Useful equations in support to hazardous area classification . 106
J.1 General . 106
J.2 Dilution with air of a flammable substance release . 106
J.3 Estimate of the time required to dilute a flammable substance release . 106
Annex K (informative) Industry codes and national standards . 108
K.1 General . 108
Bibliography . 112
Figure 1 – Dilution Volume . 29
Figure A.1 – Preferred symbols for zones . 33
Figure A.2 – Gas or vapour at low pressure (or at high pressure in case of
unpredictable release direction) . 36
Figure A.3 – Gas or vapour at high pressure . 36
Figure A.4 – Liquefied gas . 37
Figure A.5 – Flammable liquid (non boiling evaporative pool) . 37
Figure B.1 – Forms of release . 43
Figure B.2 – Specific volumetric evaporation rate of liquids . 49
Figure C.1 – Chart for assessing the degree of dilution . 57
Figure C.2 – Self diffusion of an unimpeded high velocity jet release . 61
Figure C.3 – Supply only ventilation . 62
Figure C.4 – Supply and extraction ventilation . 63
Figure C.5 – Local extraction ventilation . 64
Figure C.6 – Specific volumetric flow rate of fresh air of equivalent effective opening area . 67
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SIST EN IEC 60079-10-1:2021
IEC 60079-10-1:2020 © IEC 2020 – 5 –
Figure C.7 – Example of opposing ventilation driving forces. 68
Figure D.1 – Chart for estimating hazardous area distances . 71
Figure E.1 – Degree of dilution (Example No. 1) . 73
Figure E.2 – Hazardous distance (Example No. 1) . 74
Figure E.3 – Zone classification (Example No. 1) . 74
Figure E.4 – Degree of dilution (Example No. 2) . 76
Figure E.5 – Degree of dilution (Example No. 3) . 78
Figure E.6 – Hazardous distance (Example No. 3) . 79
Figure E.7 – Zones classification (Example No. 3) . 79
Figure E.8 – Degree of dilution (Example No. 4) . 81
Figure E.9 – Hazardous distance (Example No. 4) . 82
Figure E.10 – Zones classification (Example No. 4) . 83
Figure E.11 – Degree of dilution (Example No. 5) . 85
Figure E.12 – Hazardous distance (Example No. 5) . 86
Figure E.13 – Enclosed compressor handling natural gas . 88
Figure E.14 – Example of hazardous area classification for a compressor facility
handling natural gas (elevation) . 94
Figure E.15 – Example of hazardous area classification for a compressor facility
handling natural gas (plan) . 95
Figure F.1 – Schematic approach to classification. 96
Figure F.2 – Schematic approach to classification for continuous grade releases . 97
Figure F.3 – Schematic approach to classification for primary grade releases . 98
Figure F.4 – Schematic approach to classification for secondary grade releases . 99
Table A.1 – Hazardous area classification data sheet – Part I: Flammable substance
list and characteristics . 34
Table A.2 – Hazardous area classification data sheet – Part II: List of sources of
release . 35
Table B.1 – Suggested hole cross sections for secondary grade of releases . 42
Table B.2 – Effect of zones on openings as possible sources of release . 51
Table C.1 – Indicative outdoor ventilation velocities (u ) . 56
w
Table D.1 – Zones for grade of release and effectiveness of ventilation . 69
Table E.1 – Compressor facility handling natural gas . 88
Table E.2 – Hazardous area classification data sheet – Part I: Flammable substance
list and characteristics . 91
Table E.3 – Hazardous area classification data sheet – Part II: List of sources of
release . 92
Table K.1 – Examples of codes and standards . 109
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SIST EN IEC 60079-10-1:2021
– 6 – IEC 60079-10-1:2020 © IEC 2020
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
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...
SLOVENSKI STANDARD
oSIST prEN IEC 60079-10-1:2019
01-september-2019
Eksplozivne atmosfere - 10-1. del: Razvrstitev prostorov - Eksplozivne plinske
atmosfere
Explosive atmospheres - Part 10-1: Classification of areas - Explosive gas atmospheres
Explosionsgefährdete Bereiche - Teil 10-1: Einteilung der Bereiche -
Gasexplosionsgefährdete Bereiche
Atmosphères explosives - Partie 10-1: Classement des emplacements - Atmosphères
explosives gazeuses
Ta slovenski standard je istoveten z: prEN IEC 60079-10-1:2019
ICS:
29.260.20 Električni aparati za Electrical apparatus for
eksplozivna ozračja explosive atmospheres
oSIST prEN IEC 60079-10-1:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN IEC 60079-10-1:2019
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oSIST prEN IEC 60079-10-1:2019
31J/293/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60079-10-1 ED3
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2019-07-26 2019-10-18
SUPERSEDES DOCUMENTS:
31J/278/CD,31J/292/CC
IEC SC 31J : CLASSIFICATION OF HAZARDOUS AREAS AND INSTALLATION REQUIREMENTS
SECRETARIAT: SECRETARY:
Croatia Mr Marino Kelava
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:
TC 18,SC 61D
Other TC/SCs are requested to indicate their interest, if
any, in this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of
which they are aware and to provide supporting documentation.
TITLE:
Explosive atmospheres - Part 10-1: Classification of areas - Explosive gas atmospheres
PROPOSED STABILITY DATE: 2025
NOTE FROM TC/SC OFFICERS:
Copyright © 2019 International Electrotechnical Commission, IEC. All rights reserved. It is permitted to
download this electronic file, to make a copy and to print out the content for the sole purpose of preparing National
Committee positions. You may not copy or "mirror" the file or printed version of the document, or any part of it, for
any other purpose without permission in writing from IEC.
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oSIST prEN IEC 60079-10-1:2019
31J/293/CDV – 2 – IEC CDV 60079-10-1 © IEC 2019
1 CONTENTS
2 CONTENTS . 2
3 FOREWORD . 6
4 INTRODUCTION . 9
5 1 Scope . 10
6 2 Normative references . 10
7 3 Terms and definitions . 11
8 4 General . 15
9 4.1 Safety principles . 15
10 4.2 Hazardous Area classification objectives . 16
11 4.3 Interior of equipment containing flammable materials . 17
12 4.4 Explosion risk assessment . 17
13 4.4.1 General . 17
14 4.4.2 Zone of negligible extent . 17
15 4.5 Catastrophic failures . 18
16 4.6 Competence of personnel . 18
17 5 Hazardous area classification methodology . 18
18 5.1 General . 18
19 5.2 Classification by sources of release method . 19
20 5.3 Use of industry codes and national standards . 20
21 5.3.1 General . 20
22 5.3.2 Fuel gas installations . 20
23 5.4 Simplified methods . 20
24 5.5 Combination of methods . 21
25 6 Release of flammable substance . 21
26 6.1 General . 21
27 6.2 Sources of release . 21
28 6.3 Forms of release . 22
29 6.3.1 General . 22
30 6.3.2 Gaseous release . 23
31 6.3.3 Liquefied under pressure . 23
32 6.3.4 Liquefied by refrigeration . 24
33 6.3.5 Flammable mists . 24
34 6.3.6 Vapours . 24
35 6.3.7 Liquid releases . 24
36 7 Ventilation (or air movement) and dilution . 25
37 7.1 General . 25
38 7.2 Main types of ventilation . 26
39 7.2.1 Natural ventilation. 26
40 7.2.2 Artificial ventilation . 26
41 7.2.3 Degree of dilution . 28
42 8 Type of zone . 29
43 8.1 General . 29
44 8.2 Influence of grade of the source of release . 29
45 8.3 Influence of dilution . 29
46 8.4 Influence of availability of ventilation . 29
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oSIST prEN IEC 60079-10-1:2019
IEC CDV 60079-10-1© IEC 2019 – 3 – 31J/293/CDV
47 9 Extent of zone . 30
48 10 Documentation . 30
49 10.1 General . 30
50 10.2 Drawings, data sheets and tables . 31
51 Annex A (informative) Suggested presentation of hazardous areas . 32
52 A.1 Hazardous area zones – Preferred symbols . 32
53 A.2 Hazardous area suggested shapes . 35
54 Annex B (informative) Estimation of sources of release. 37
55 B.1 Symbols . 37
56 B.2 Examples of grade of release . 37
57 B.2.1 General . 37
58 B.2.2 Sources giving a continuous grade of release . 38
59 B.2.3 Sources giving a primary grade of release . 38
60 B.2.4 Sources giving a secondary grade of release . 38
61 B.3 Assessment of grades of release . 38
62 B.4 Summation of releases . 39
63 B.5 Hole size and source radius . 40
64 B.6 Forms of release . 42
65 B.7 Release rate . 43
66 B.7.1 General . 43
67 B.7.2 Estimation of Release Rate . 43
68 B.7.3 Release rate of evaporative pools . 46
69 B.8 Release from openings in buildings . 48
70 B.8.1 General . 48
71 B.8.2 Openings as possible sources of release . 48
72 B.8.3 Openings classification . 48
73 Annex C (informative) Ventilation guidance . 50
74 C.1 Symbols . 50
75 C.2 General . 51
76 C.3 Assessment of ventilation and dilution and its influence on hazardous area . 51
77 C.3.1 General . 51
78 C.3.2 Effectiveness of ventilation . 52
79 C.3.3 Criteria for dilution . 52
80 C.3.4 Assessment of ventilation velocity . 53
81 C.3.5 Assessment of the degree of dilution . 54
82 C.3.6 Dilution in a room . 56
83 C.3.7 Criteria for availability of ventilation . 57
84 C.4 Examples of ventilation arrangements and assessments . 58
85 C.4.1 Introduction . 58
86 C.4.2 Jet release in a large building . 59
87 C.4.3 Jet release in a small naturally ventilated building . 60
88 C.4.4 Jet release in a small artificially ventilated building . 60
89 C.4.5 Release with low velocity . 61
90 C.4.6 Fugitive emissions . 61
91 C.4.7 Local ventilation-extraction . 62
92 C.5 Natural Ventilation in buildings . 62
93 C.5.1 General . 62
94 C.5.2 Wind induced ventilation . 62
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95 C.5.3 Buoyancy induced ventilation. 63
96 C.5.4 Combination of the natural ventilation induced by wind and buoyancy . 65
97 Annex D (informative) Estimation of hazardous zones. 67
98 D.1 General . 67
99 D.2 Estimating types of the zones . 67
100 D.3 Estimating the extent of the hazardous zone . 68
101 Annex E (informative) Examples of hazardous area classification . 70
102 E.1 General . 70
103 E.2 Examples . 70
104 E.3 Example case study for hazardous area classification . 84
105 Annex F (informative) Schematic approach to classification of hazardous areas . 94
106 F.1 Schematic approach to classification of hazardous areas . 94
107 F.2 Schematic approach to classification of hazardous areas . 95
108 F.3 Schematic approach to classification of hazardous areas . 96
109 F.4 Schematic approach to classification of hazardous areas . 97
110 Annex G (informative) Flammable mists . 98
111 Annex H (informative) Hydrogen . 101
112 Annex I (informative) Hybrid mixtures . 103
113 I.1 General . 103
114 I.2 Use of ventilation . 103
115 I.3 Concentration limits . 103
116 I.4 Chemical reactions . 103
117 I.5 Energy/Temperature limits . 103
118 I.6 Zoning requirements . 103
119 Annex J (informative) Useful equations in support to hazardous area classification . 104
120 J.1 General . 104
121 J.2 Dilution with air of a flammable substance release . 104
122 J.3 Room circulation airflow rates for the releases arising from an enclosure with
123 a fan . 104
124 where 105
125 J.4 Estimate of the time required to dilute a flammable substance release . 105
126 Annex K (informative) Industry codes and national standards . 107
127 K.1 General . 107
128 Bibliography . 109
129
130 Figure 1 – Dilution Volume . 28
131 Figure A.1 – Preferred symbols for hazardous area zones . 32
132 Figure A.2 – Gas/vapour at low pressure (or at high pressure in case of unpredictable
133 release direction) . 35
134 Figure A.3 – Gas/vapour at high pressure . 35
135 Figure A.4 – Liquefied gas . 36
136 Figure A.5 – Flammable liquid (non boiling evaporative pool) . 36
137 Figure B.1 – Forms of release . 42
138 Figure B.2 – Volumetric evaporation rate of liquids . 47
139 Figure C.1 – Chart for assessing the degree of dilution . 55
140 Figure C.2 – Self diffusion of an unimpeded high velocity jet release . 59
141 Figure C.3 – Supply only ventilation . 60
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142 Figure C.4 – Supply and extraction ventilation . 61
143 Figure C.5 – Local extraction ventilation . 62
2
144 Figure C.6 – Volumetric flow rate of fresh air per m of equivalent effective opening
145 area 65
146 Figure C.7 – Example of opposing ventilation driving forces . 66
147 Figure D.1 – Chart for estimating hazardous area distances . 69
148 Figure E.1 – Degree of dilution (Example No. 1) . 71
149 Figure E.2 – Hazardous distance (Example No. 1) . 72
150 Figure E.3 – Zone classification (Example No. 1) . 72
151 Figure E.4 – Degree of dilution (Example No. 2) . 74
152 Figure E.5 – Degree of dilution (Example No. 3) . 76
153 Figure E.6 – Hazardous distance (Example No. 3) . 77
154 Figure E.7 – Zones classification (Example No. 3) . 77
155 Figure E.8 – Degree of dilution (Example No. 4) . 79
156 Figure E.9 – Hazardous distance (Example No. 4) . 80
157 Figure E.10 – Zones classification (Example No. 4) . 80
158 Figure E.11– Degree of dilution (Example No. 5) . 83
159 Figure E.13 – Enclosed compressor handling natural gas . 86
160 Figure E.14 – Example of hazardous area classification for a compressor facility
161 handling natural gas (elevation) . 92
162 Figure E.15 – Example of hazardous area classification for a compressor facility
163 handling natural gas (plan) . 93
164 Figure F.1– Schematic approach to classification . 94
165 Figure F.2 – Schematic approach to classification for continuous grade releases . 95
166 Figure F.3 – Schematic approach to classification for primary grade releases . 96
167 Figure F.4 – Schematic approach to classification for secondary grade releases . 97
168
169 Table A.1 − Hazardous area classification data sheet – Part I: Flammable substance
170 list and characteristics . 33
171 Table A.2 − Hazardous area classification data sheet − Part II: List of sources of
172 release . 34
173 Table B.1 – Suggested hole cross sections for secondary grade of releases . 41
174 Table B.2 – Effect of hazardous zones on openings as possible sources of release . 49
175 Table C.1 – Indicative outdoor ventilation velocities (u ). 54
w
176 Table D.1 – Zones for grade of release and effectiveness of ventilation . 67
177 Table E.1 – Compressor facility handling natural gas . 87
178 Table E.2 – Hazardous area classification data sheet − Part I: Flammable substance
179 list and characteristics . 89
180 Table E.3 – Hazardous area classification data sheet − Part II: List of sources of
181 release (1 of 2) . 90
182 Table K.1 – Examples of codes and standards . 108
183
184
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185 INTERNATIONAL ELECTROTECHNICAL COMMISSION
186 ____________
187
188 EXPLOSIVE ATMOSPHERES –
189
190 Part 10-1: Classification of areas –
191 Explosive gas atmospheres
192
193 FOREWORD
194 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
195 all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
196 international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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198 Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
199 Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
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202 with the International Organization for Standardization (ISO) in accordance with conditions determined by
203 agreement between the two organizations.
204 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
205 consensus of opinion on the relevant subjects since each technical committee has representation from all
206 interested IEC National Committees.
207 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
208 Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
209 Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
210 misinterpretation by any end user.
211 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
212 transparently to the maximum extent possible in their national and regional publications. Any divergence
213 between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
214 the latter.
215 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
216 assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
217 services carried out by independent certification bodies.
218 6) All users should ensure that they have the latest edition of this publication.
219 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
220 members of its technical committees and IEC National Committees for any personal injury, property damage or
221 other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
222 expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
223 Publications.
224 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
225 indispensable for the correct application of this publication.
226 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
227 patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
228 International Standard IEC 60079-10-1 has been prepared by subcommittee 31J:
229 Classification of hazardous areas and installation requirements, of IEC technical
230 committee 31: Equipment for explosive atmospheres.
231 This bilingual version (2016-01) corresponds to the English version, published in 2015-09.
232 This third edition of IEC 60079-10-1 cancels and replaces the second edition, published in
233 2015, and constitutes a technical revision. The significant technical changes with respect to
234 the previous edition are as follows:
235
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Type
Minor and Major
Changes Clause editorial Extension technical
changes changes
Deleting item e) from the Scope exemptions 1 X
Introducing new terms and the definitions 3 X
Introducing new clause 4.4.1 Zone of negligible
4 X X
extent
Introducing new clause 5.3.1 Fuel gas installations 5 X X X
Introducing Figure 1 – Dilution volume
7 X
Upgrading Table A.1 with UFL and its column 15
Annex A X X
heading with the ‘source of data’
Updating the flow-chart in Figure B.1 Annex B X
Updating equations for evaporation rate with the
Annex B X X
recent source modifications
Updating the chart in Figure B.2 according to the
updated equations for evaporation rate and the Annex B X
ventilation velocity of 0,25 m/s
Restructuring Table C.1 Annex C X
Abolishing safety factor k and deleting it from the
Annex C, D X
horizontal axis of the charts in
...
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