IEC 60079-10-1:2020
(Main)Explosive atmospheres - Part 10-1: Classification of areas - Explosive gas atmospheres
Explosive atmospheres - Part 10-1: Classification of areas - Explosive gas atmospheres
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.
Atmosphères explosives - Partie 10-1: Classification des emplacements - Atmosphères explosives gazeuses
l'IEC 60079-10-1:2020 concerne la classification des emplacements dans lesquels des phénomènes dangereux dus à des gaz ou vapeurs inflammables peuvent apparaître, et peut ainsi constituer une base pour la conception, l'exploitation et la maintenance correctes du matériel utilisé dans de tels emplacements.
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. Des brouillards inflammables peuvent se former ou être présents en même temps que les vapeurs inflammables. Dans ce type de cas, l’application stricte des détails du présent document peut ne pas être appropriée. Les brouillards inflammables peuvent également se former lorsque les liquides qui ne sont pas considérés comme dangereux en raison du point d’éclair élevé sortent sous pression. Dans ces cas, les classifications et détails donnés dans le présent document ne s’appliquent pas. Des informations relatives aux brouillards inflammables sont données à l’Annexe G.
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.
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IEC 60079-10-1 ®
Edition 3.0 2020-12
COMMENTED VERSION
INTERNATIONAL
STANDARD
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Explosive atmospheres –
Part 10-1: Classification of areas – Explosive gas atmospheres
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.260.20 ISBN 978-2-8322-9213-6
– 2 – IEC 60079-10-1:2020 CMV © IEC 2020
CONTENTS
FOREWORD . 6
INTRODUCTION . 2
1 Scope . 11
2 Normative references . 12
3 Terms and definitions . 12
4 General . 17
4.1 Safety principles . 17
4.2 Hazardous area classification objectives . 18
4.3 Interior of equipment containing flammable materials . 18
4.4 Explosion risk assessment . 19
4.4.1 General . 19
4.4.2 Zone of negligible extent. 19
4.5 Catastrophic failures . 20
4.6 Competence of personnel . 20
5 Hazardous area classification methodology . 20
5.1 General . 20
5.2 Classification by sources of release method . 21
5.3 Use of industry codes and national standards . 22
5.3.1 General . 22
5.3.2 Fuel gas installations . 22
5.4 Simplified methods. 22
5.5 Combination of methods . 22
6 Release of flammable substance . 23
6.1 General . 23
6.2 Sources of release . 23
6.3 Forms of release . 24
6.3.1 General . 24
6.3.2 Gaseous release . 25
6.3.3 Liquefied under pressure release . 25
6.3.4 Liquefied by refrigeration release . 26
6.3.5 Aerosols Flammable mists release . 26
6.3.6 Vapours release . 26
6.3.7 Liquid release . 26
7 Ventilation (or air movement) and dilution . 27
7.1 General . 27
7.2 Main types of ventilation . 28
7.2.1 General . 28
7.2.2 Natural ventilation . 28
7.2.3 Artificial ventilation . 29
7.2.4 Degree of dilution . 30
8 Type of zone . 31
8.1 General . 31
8.2 Influence of grade of the source of release . 32
8.3 Influence of dilution . 32
8.4 Influence of availability of ventilation . 32
9 Extent of zone . 32
10 Documentation . 33
10.1 General . 33
10.2 Drawings, data sheets and tables . 34
Annex A (informative) Suggested presentation of hazardous areas . 35
A.1 Hazardous area zones – Preferred symbols for zones . 35
A.2 Hazardous area suggested shapes . 38
Annex B (informative) Estimation of sources of release . 40
B.1 Symbols . 40
B.2 Examples of grade of release . 40
B.2.1 General . 40
B.2.2 Sources giving a continuous grade of release . 41
B.2.3 Sources giving a primary grade of release . 41
B.2.4 Sources giving a secondary grade of release . 41
B.3 Assessment of grades of release . 41
B.4 Summation of releases . 42
B.5 Hole size and source radius . 43
B.6 Forms of release . 45
B.7 Release rate . 46
B.7.1 General . 46
B.7.2 Estimation of release rate . 47
B.7.3 Release rate of evaporative pools . 49
B.8 Release from openings in buildings . 52
B.8.1 General . 52
B.8.2 Openings as possible sources of release . 53
B.8.3 Openings classification . 53
Annex C (informative) Ventilation guidance . 55
C.1 Symbols . 55
C.2 General . 56
C.3 Assessment of ventilation and dilution and its influence on hazardous area . 57
C.3.1 General . 57
C.3.2 Effectiveness of ventilation . 57
C.3.3 Criteria for dilution . 58
C.3.4 Assessment of ventilation velocity . 58
C.3.5 Assessment of the degree of dilution . 59
C.3.6 Dilution in a room . 59
C.3.7 Criteria for availability of ventilation . 63
C.4 Examples of ventilation arrangements and assessments . 65
C.4.1 Introduction . 65
C.4.2 Jet release in a large building . 65
C.4.3 Jet release in a small naturally ventilated building . 66
C.4.4 Jet release in a small artificially ventilated building . 67
C.4.5 Release with low velocity . 68
C.4.6 Fugitive emissions . 68
C.4.7 Local ventilation-extraction . 69
C.5 Natural Ventilation in buildings . 69
C.5.1 General . 69
C.5.2 Wind induced ventilation . 70
– 4 – IEC 60079-10-1:2020 CMV © IEC 2020
C.5.3 Buoyancy induced ventilation . 71
C.5.4 Combination of the natural ventilation induced by wind and buoyancy . 73
Annex D (informative) Estimation of
...
IEC 60079-10-1 ®
Edition 3.0 2020-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
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Explosive atmospheres –
Part 10-1: Classification of areas – Explosive gas atmospheres
Atmosphères explosives –
Partie 10-1: Classification des emplacements – Atmosphères explosives
gazeuses
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
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About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.
About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.
IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org
The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,
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committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary
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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
– 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
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 .
...
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