IEC 60079-26:2021

Explosive atmospheres - Part 26: Equipment with Separation Elements or combined Levels of Protection

IEC 60079-26:2021 specifies requirements for construction, testing and marking for Ex Equipment that contains parts of the equipment with different Equipment Protection Levels (EPLs) and a separation element. This equipment is mounted across a boundary where different EPLs are required, for example between different gas hazardous areas, dust hazardous areas or gas hazardous areas adjacent to dust hazardous areas.
Separation elements are considered for both electrical and non-electrical equipment. If mechanical energy can be transformed into a potential ignition source, additionally an ignition hazard assessment in accordance with ISO 80079-36 is performed and appropriate measures are undertaken.
This document also specifies requirements for the combination of two Types of Protection, each with EPL Gb, to achieve EPL Ga.
This document supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this document conflicts with a requirement of IEC 60079-0, the requirement of this document takes precedence. This fourth edition cancels and replaces the third edition and constitutes a technical revision.
Please see the IEC 60079-26:2020 foreword for a description of the main changes with respect to the previous edition.

Atmosphères explosives - Partie 26: Appareil avec éléments de séparation ou niveaux de protection combinés

IEC 60079-26:2021 spécifie les exigences de construction, d’essai et de marquage, par exemple, des appareils contenant des parties d’appareils présentant différents niveaux de protection de l’appareil (EPL, Equipment Protection Level) et un élément de séparation. Cet appareil est installé en chevauchement sur des emplacements pour lesquels différents EPL sont exigés, par exemple entre différentes zones gazeuses dangereuses, entre différentes zones poussiéreuses dangereuses ou entre des zones gazeuses dangereuses placées à côté de zones poussiéreuses dangereuses.
EXEMPLE: Appareil installé dans le mur des réservoirs de stockage situés dans la Zone 1 et englobant la Zone 0.
Les éléments de séparation sont pris en considération tant pour les appareils électriques que pour les appareils non électriques. Si l’énergie mécanique peut devenir une source potentielle d’inflammation, une évaluation du danger d’inflammation selon l’ISO 80079-36 est réalisée, et des mesures appropriées sont prises. Les mesures appropriées peuvent être sélectionnées dans l’ISO 80079-37 ou l’IEC TS 60079-42.
Le présent document spécifie également les exigences relatives à la combinaison de deux modes de protection, chacun avec EPL Gb, pour atteindre EPL Ga. Des exemples sont donnés en 4.2.
Le présent document complète et modifie les exigences générales de l’IEC 60079-0. Lorsqu’une exigence du présent document entre en contradiction avec une exigence de l’IEC 60079-0, l’exigence du présent document prévaut.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente.

General Information

• Status: Published
• Publication Date: 24-Feb-2021
• ICS: 29.260.20 - Electrical apparatus for explosive atmospheres
• Technical Committee: TC 31 - Equipment for explosive atmospheres
• Drafting Committee: MT 60079-26 - TC 31/MT 60079-26
• Current Stage: PPUB - Publication issued
• Start Date: 26-Feb-2021
• Completion Date: 25-Feb-2021

Relations

• Revises: IEC 60079-26:2014 - Explosive atmospheres - Part 26: Equipment with Equipment Protection Level (EPL) Ga
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60079-26 ®
Edition 4.0 2021-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Explosive atmospheres –
Part 26: Equipment with Separation Elements or combined Levels of Protection

Atmosphères explosives –
Partie 26: Appareil avec éléments de séparation ou niveaux de protection
combinés
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IEC 60079-26 ®
Edition 4.0 2021-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Explosive atmospheres –
Part 26: Equipment with Separation Elements or combined Levels of Protection

Atmosphères explosives –
Partie 26: Appareil avec éléments de séparation ou niveaux de protection

combinés
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.260.20 ISBN 978-2-8322-9390-4

– 2 – IEC 60079-26:2021 © IEC 2021
CONTENTS
FOREWORD . 4
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Ex Equipment with two combined Types of Protection . 8
4.1 General . 8
4.2 Basic requirements . 8
4.3 Electrical Connections . 9
5 Ex Equipment containing parts with different EPLs and a separation element . 9
5.1 General . 9
5.2 Separation elements . 9
5.2.1 General . 9
5.2.2 Basic requirements . 10
5.2.3 Mechanical partition walls . 10
5.2.4 Metallic partition walls with gas-tight conductor bushings . 10
5.2.5 Partition wall supplemented with a joint . 11
5.2.6 Partition wall for explosive gas atmospheres supplemented with natural
ventilation . 11
5.2.7 Requirements depending on the thickness of the partition wall . 12
6 Process connection . 13
7 Type tests . 14
7.1 Standardized Types of Protection . 14
7.2 Separation elements . 14
7.3 Temperature evaluation . 14
8 Marking . 14
8.1 General . 14
8.2 Ex Equipment with two combined Types of Protection . 14
8.3 Ex Equipment containing parts with different EPLs. 15
8.4 Examples of marking:. 15
9 Instructions . 16
9.1 Separation elements . 16
9.2 Process connection . 16
9.3 EPL allocation . 16
Annex A (normative)  Types of construction for separation elements . 17
Bibliography . 23

Figure 1 – Partition wall with a conductor bushing considered as gas diffusion tight. 11
Figure 2 – Example of a separation element with a cylindrical shaft joint and ventilation . 12
Figure 3 – Example g) of marking of equipment with a separation element. 15

Table 1 – Requirements for Ex Equipment containing parts with different EPLs. . 9
Table A.1 – Ex Equipment with separation elements mounted at a boundary of Zone 0. 17
Table A.2 – Ex Equipment with separation elements mounted at a boundary of Zone 1. 18
Table A.3 – Ex Equipment with separation elements mounted at a boundary of Zone 20 . 19
Table A.4 – Ex Equipment with separation elements mounted at a boundary of Zone 21 . 19

Table A.5 – Ex Equipment with separation elements mounted at a boundary of Zone 0
in Zone 21 or 22 . 20
Table A.6 – Ex Equipment with separation elements mounted at a boundary of Zone 1
in Zone 21 or 22 . 20
Table A.7 – Ex Equipment with separation elements mounted at a boundary of Zone 20
in Zone 1 or 2 . 21
Table A.8 – Ex Equipment with separation elements mounted at a boundary of Zone 21
in Zone 1 or 2 . 22

– 4 – IEC 60079-26:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EXPLOSIVE ATMOSPHERES –
Part 26: Equipment with Separation Elements
or combined Levels of Protection

FOREWORD
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