IEC 60079-26:2021

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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