IEC 60079-11:2023
(Main)Explosive atmospheres - Part 11: Equipment protection by intrinsic safety "i"
Explosive atmospheres - Part 11: Equipment protection by intrinsic safety "i"
IEC 60079-11:2023 specifies the construction and testing of intrinsically safe apparatus intended for use in explosive atmospheres, and for associated apparatus which is intended for connection to intrinsically safe circuits which enter such atmospheres.
This Type of Protection is applicable to electrical equipment in which the electrical circuits themselves are incapable of causing ignition of a surrounding explosive atmosphere. This includes electrical equipment which contains circuits that are intrinsically safe only under certain conditions, for example under battery supply with mains supply removed.
This document is also applicable to electrical equipment or parts of electrical equipment located outside the explosive atmosphere or protected by another Type of Protection listed in IEC 60079 0, where the intrinsic safety of the electrical circuits in the explosive atmosphere may depend upon the design and construction of such electrical equipment or parts of such electrical equipment. The electrical circuits exposed to the explosive atmosphere are assessed for use in such atmospheres by applying this document.
This document applies to sensors connected to intrinsically safe circuits but does not apply to the protection of catalytic elements for Group IIC or Group IIB + H2.
This document does not apply to Ex Equipment cable glands.
The requirements for intrinsically safe systems are provided in IEC 60079-25.
This document supplements and modifies the general requirements of IEC 60079-0, except as indicated in Table 1. Where a requirement of this document conflicts with a requirement of IEC 60079-0, the requirement of this document takes precedence.
Unless otherwise stated, the requirements in this document are applicable to both intrinsically safe apparatus and associated apparatus, and the generic term "apparatus" is used throughout the standard.
As this document applies only to electrical equipment, the term "equipment" used in the standard always means "electrical equipment".
This document applies to apparatus for use under the atmospheric conditions of IEC 60079 0 with additional requirements for use at extended atmospheric pressures in the range from 60 kPa (0,6 bar), up to 110 kPa (1,1 bar).
This seventh edition cancels and replaces the sixth edition published in 2011. This edition constitutes a technical revision.
The identification and significance of the changes between IEC 60079-11, Edition 7 (2022) and IEC 60079-11, Edition 6 (2011 + Corrigendum 1 (2012)) can be found in the table of changes in the foreword of the publication.
The contents of the corrigendum 1 (2023-06), the Interpretation sheets 1 (2024-05), 2 (2024-05) and 3 (2024-08) have been included in this copy.
Atmosphères explosives - Partie 11: Protection de l’appareil par sécurité intrinsèque "i"
IEC 60079-11:2023 spécifie la construction et les essais pour le matériel électrique de sécurité intrinsèque destiné à être utilisé dans les atmosphères explosives et pour le matériel électrique associé destiné à être relié à des circuits de sécurité intrinsèque qui entrent dans de telles atmosphères.
Ce mode de protection s’applique à l’appareil électrique dont les circuits électriques sont eux mêmes incapables de provoquer une inflammation dans l’atmosphère explosive environnante. Il inclut l’appareil électrique qui contient des circuits qui sont de sécurité intrinsèque uniquement dans certaines conditions, par exemple alimentés par batterie et alimentation réseau coupée.
Le présent document s’applique également à l’appareil électrique ou aux parties d’appareil électrique situés hors de l’atmosphère explosive ou protégés par un autre mode de protection cité dans l’IEC 60079 0, si la sécurité intrinsèque des circuits électriques situés dans l’atmosphère explosive peut dépendre de la conception et de la construction de cet appareil électrique ou de ces parties d’appareil électrique. Les circuits électriques exposés à une atmosphère explosive sont évalués en vue de leur emploi dans de telles atmosphères en appliquant le présent document.
Le présent document s’applique aux capteurs reliés à des circuits de sécurité intrinsèque, mais elle ne s’applique pas à la protection d’éléments catalytiques pour le Groupe IIC ou le Groupe IIB + H2.
Le présent document ne s’applique pas aux entrées de câbles d’appareils Ex.
Les exigences pour les circuits de sécurité intrinsèque sont fournies dans l’IEC 60079-25.
Le présent document complète et modifie les exigences générales de l’IEC 60079-0. Si une exigence du présent document entre en conflit avec une exigence de l’IEC 60079-0, l’exigence du présent document prévaut.
Sauf indication contraire, les exigences du présent document s’appliquent au matériel de sécurité intrinsèque et au matériel associé, et le terme générique "matériel" est utilisé dans toute la norme.
Comme le présent document s’applique uniquement à l’appareil électrique, le terme "appareil" utilisé dans la norme signifie toujours "appareil électrique".
Le présent document s’applique au matériel à utiliser dans les conditions atmosphériques de l’IEC 60079-0 avec les exigences supplémentaires pour son utilisation à des pressions atmosphériques supérieures comprises entre 60 kPa (0,6 bar) et 110 kPa (1,1 bar).
Cette septième édition annule et remplace la sixième édition parue en 2011. Cette édition constitue une révision technique
L'identification et la signification des changements entre la CEI 60079-11, Édition 7 (2022) et la CEI 60079-11, Édition 6 (2011 + Corrigendum 1 (2012)) peuvent être trouvées dans le tableau des modifications dans l'avant-propos de la publication.
Les contenus du corrigendum 1 (2023-06), des feuilles d'interprétation 1 (2024-05), 2 (2024-05) et 3 (2024-08) s'appliquent à la version anglaise uniquement.
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IEC 60079-11 ®
Edition 7.0 2023-01
INTERNATIONAL
STANDARD
colour
inside
Explosive atmospheres –
Part 11: Equipment protection by intrinsic safety "i"
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
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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.
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IEC 60079-11 ®
Edition 7.0 2023-01
INTERNATIONAL
STANDARD
colour
inside
Explosive atmospheres –
Part 11: Equipment protection by intrinsic safety "i"
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.260.20 ISBN 978-2-8322-6271-9
– 2 – IEC 60079-11:2023 © IEC 2023
CONTENTS
FOREWORD . 10
1 Scope . 23
2 Normative references . 30
3 Terms, definitions and abbreviated terms . 31
3.1 Terms and definitions . 31
3.2 Abbreviated terms . 35
4 Equipment grouping, classification and Levels of Protection of apparatus . 35
5 Ignition compliance requirements . 36
5.1 General . 36
5.2 Conditions for assessment . 36
5.2.1 General . 36
5.2.2 Level of Protection "ia" . 37
5.2.3 Level of Protection "ib" . 38
5.2.4 Level of Protection "ic". 38
5.2.5 Non-shock hazard equipment or systems . 39
5.3 Spark ignition compliance . 39
5.3.1 General . 39
5.3.2 Levels of Protection "ia" and "ib" . 40
5.3.3 Level of Protection "ic". 40
5.3.4 Application of safety factors . 41
5.3.5 Circuits without controlled semiconductor limitation . 41
5.3.6 Circuits with controlled semiconductor limitation . 42
5.4 Thermal ignition compliance . 43
5.4.1 General . 43
5.4.2 Temperature of small components for Group I and Group II . 43
5.4.3 Wiring within intrinsically safe apparatus for Group I and Group II . 43
5.4.4 PCB tracks for Group I and Group II . 45
5.4.5 Intrinsically safe apparatus and component temperature for dusts . 48
5.5 Simple apparatus . 48
6 Apparatus construction . 49
6.1 General . 49
6.2 Enclosures . 49
6.2.1 General . 49
6.2.2 Apparatus complying with Table 7 . 50
6.2.3 Apparatus complying with Table 8 or Table 9 . 50
6.2.4 Enclosures for Group IIIC intrinsically safe apparatus . 50
6.2.5 Protection of separations . 50
6.3 Connection facilities for external circuits . 51
6.3.1 Terminals . 51
6.3.2 Earth Terminals . 53
6.3.3 Plugs and sockets . 53
6.3.4 Permanently connected cable . 53
6.3.5 Connections and accessories for intrinsically safe apparatus for use in
non-hazardous area . 54
6.4 Internal connections and connectors . 55
6.4.1 General . 55
6.4.2 Infallible connections . 55
6.4.3 Connectors for internal connections, plug-in cards and components . 57
6.4.4 Earth conductors and connections . 57
6.5 Separation of conductive parts . 58
6.5.1 Separations on which intrinsic safety depends . 58
6.5.2 Separation distances according to Table 7. 58
6.5.3 Reduced separation distances . 59
6.5.4 Failure of separations . 59
6.5.5 Voltage between conductive parts . 65
6.5.6 Types of separation . 65
6.5.7 Composite separations . 72
6.5.8 Printed circuit board assemblies . 73
6.5.9 Separation by metal parts . 75
6.5.10 Separation by non-metallic insulating partitions . 75
6.5.11 Insulation of internal wiring . 76
6.6 Encapsulation . 76
6.6.1 General . 76
6.6.2 Encapsulation used for the exclusion of explosive atmospheres . 77
6.6.3 Mechanical protection to avoid access to parts . 80
6.6.4 Encapsulation used for protection of a fuse . 81
6.6.5 Encapsulation used to provide separation . 81
6.6.6 Encapsulation used to enhance the rating of protective components . 81
6.6.7 Free space within the encapsulation . 81
6.7 Specification of coating, encapsulation materials . 83
6.8 Protection against polarity reversal . 83
6.9 Dielectric strength requirement . 83
7 Characteristics and failure of components and assemblies . 84
7.1 Rating of components on which intrinsic safety depends . 84
7.2 Failure of components . 84
7.3 Manufacturing variation . 84
7.4 Resistors . 85
7.4.1 General . 85
7.4.2 Resistors on which intrinsic safety depends . 85
7.5 Capacitors . 86
7.5.1 General . 86
7.5.2 Capacitors on which intrinsic safety depends . 86
7.5.3 Blocking capacitors . 87
7.5.4 Infallible filter capacitors . 87
7.6 Inductors and windings . 88
7.6.1 General . 88
7.6.2 Inductors on which intrinsic safety depends . 88
7.6.3 Infallibly insulated inductors . 88
7.6.4 Damping windings . 89
7.6.5 Common mode choke coils (EMI suppression filters) . 89
7.7 Semiconductors . 90
7.7.1 Failure of semiconductors . 90
7.7.2 Semiconductors on which intrinsic safety depends . 91
7.7.3 Transient effects on semiconductors on which intrinsic safety depends . 91
7.7.4 Semiconductors in shunt voltage limiters . 91
7.7.5 Shunt assembly on which intrinsic safety depends . 92
– 4 – IEC 60079-11:2023 © IEC 2023
7.7.6 Safety assemblies infallible against failure to limit voltage . 92
7.7.7 Semiconductor current limiters . 92
7.7.8 Use of programmable components . 92
7.8 Transformers . 93
7.8.1 General .
...
IEC 60079-11 ®
Edition 7.0 2023-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Explosive atmospheres –
Part 11: Equipment protection by intrinsic safety "i"
Atmosphères explosives –
Partie 11: Protection de l’appareil par sécurité intrinsèque "i"
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
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Switzerland
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 IEC Products & Services Portal - products.iec.ch
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containing more than 22 300 terminological entries in English
details all new publications released. Available online and once
and French, with equivalent terms in 19 additional languages.
a month by email.
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(IEV) online.
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IEC 60079-11 ®
Edition 7.0 2023-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Explosive atmospheres –
Part 11: Equipment protection by intrinsic safety "i"
Atmosphères explosives –
Partie 11: Protection de l’appareil par sécurité intrinsèque "i"
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.260.20 ISBN 978-2-8322-7447-7
– 2 – IEC 60079-11:2023 © IEC 2023
CONTENTS
FOREWORD . 10
1 Scope . 23
2 Normative references . 30
3 Terms, definitions and abbreviated terms . 31
3.1 Terms and definitions . 31
3.2 Abbreviated terms . 35
4 Equipment grouping, classification and Levels of Protection of apparatus . 35
5 Ignition compliance requirements . 36
5.1 General . 36
5.2 Conditions for assessment . 36
5.2.1 General . 36
5.2.2 Level of Protection "ia" . 37
5.2.3 Level of Protection "ib" . 38
5.2.4 Level of Protection "ic". 38
5.2.5 Non-shock hazard equipment or systems . 39
5.3 Spark ignition compliance . 39
5.3.1 General . 39
5.3.2 Levels of Protection "ia" and "ib" . 40
5.3.3 Level of Protection "ic". 40
5.3.4 Application of safety factors . 41
5.3.5 Circuits without controlled semiconductor limitation . 41
5.3.6 Circuits with controlled semiconductor limitation . 42
5.4 Thermal ignition compliance . 43
5.4.1 General . 43
5.4.2 Temperature of small components for Group I and Group II . 43
5.4.3 Wiring within intrinsically safe apparatus for Group I and Group II . 43
5.4.4 PCB tracks for Group I and Group II . 45
5.4.5 Intrinsically safe apparatus and component temperature for dusts . 48
5.5 Simple apparatus . 48
6 Apparatus construction . 49
6.1 General . 49
6.2 Enclosures . 49
6.2.1 General . 49
6.2.2 Apparatus complying with Table 7 . 50
6.2.3 Apparatus complying with Table 8 or Table 9 . 50
6.2.4 Enclosures for Group IIIC intrinsically safe apparatus . 50
6.2.5 Protection of separations . 50
6.3 Connection facilities for external circuits . 51
6.3.1 Terminals . 51
6.3.2 Earth Terminals . 53
6.3.3 Plugs and sockets . 53
6.3.4 Permanently connected cable . 53
6.3.5 Connections and accessories for intrinsically safe apparatus for use in
non-hazardous area . 54
6.4 Internal connections and connectors . 55
6.4.1 General . 55
6.4.2 Infallible connections . 55
6.4.3 Connectors for internal connections, plug-in cards and components . 57
6.4.4 Earth conductors and connections . 57
6.5 Separation of conductive parts . 58
6.5.1 Separations on which intrinsic safety depends . 58
6.5.2 Separation distances according to Table 7. 58
6.5.3 Reduced separation distances . 59
6.5.4 Failure of separations . 59
6.5.5 Voltage between conductive parts . 65
6.5.6 Types of separation . 65
6.5.7 Composite separations . 72
6.5.8 Printed circuit board assemblies . 73
6.5.9 Separation by metal parts . 75
6.5.10 Separation by non-metallic insulating partitions . 75
6.5.11 Insulation of internal wiring . 76
6.6 Encapsulation . 76
6.6.1 General . 76
6.6.2 Encapsulation used for the exclusion of explosive atmospheres . 77
6.6.3 Mechanical protection to avoid access to parts . 80
6.6.4 Encapsulation used for protection of a fuse . 81
6.6.5 Encapsulation used to provide separation . 81
6.6.6 Encapsulation used to enhance the rating of protective components . 81
6.6.7 Free space within the encapsulation . 81
6.7 Specification of coating, encapsulation materials . 83
6.8 Protection against polarity reversal . 83
6.9 Dielectric strength requirement . 83
7 Characteristics and failure of components and assemblies . 84
7.1 Rating of components on which intrinsic safety depends . 84
7.2 Failure of components . 84
7.3 Manufacturing variation . 84
7.4 Resistors . 85
7.4.1 General .
...
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