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dnaSRPS EN IEC 60079-31:2024

Explosive atmospheres - Part 31: Equipment dust ignition protection by enclosure "t"

General information

50.60     Dec 3, 2021



European Norm




<!-- NEW! -->IEC 60079-31:2022 is available as <a href="">IEC 60079-31:2022 RLV</a> which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.</br></br>IEC 60079-31:2022 is applicable to equipment protected by enclosure and surface temperature limitation for use in explosive dust atmospheres. It specifies requirements for design, construction and testing of Ex Equipment and Ex Components. 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 document does not apply to dusts of explosives, which do not require atmospheric oxygen for combustion, or to pyrophoric substances. This document does not apply to Ex Equipment or Ex Components intended for use in underground parts of mines as well as those parts of surface installations of such mines endangered by firedamp and/or combustible dust. This document does not take account of any risk due to an emission of flammable or toxic gas from the dust. This third edition cancels and replaces the second edition published in 2013. This edition constitutes a technical revision. Main significant changes from the previous edition are:

1) Document has been restructured from edition 2

2) Fault current rating of interrupting contacts in clauses 4.3.1 and 4.4.1, major change type C1

3) Cells and batteries in clauses and, major change type C2

4) Overload or malfunction condition for the determination of temperature class for "tb" converter fed rotating electric machines, major change type C3

5) Additional requirements for entry devices with dust ignition protection by enclosure "t", major change type C4

Information about the background of ‘Major Technical Changes’

C1 – Ex Equipment having Level of Protection "ta" shall be rated for connection to a circuit with a prospective short circuit current of not greater than 1.5 kA. For Ex Equipment having Level of Protection "tb" or "tc" which is intended for mains connection and intended to interrupt fault current above 10kA, the equipment shall have a rated maximum short circuit withstand current, be tested according to, and be marked according to Clause 7.

C2 – For Ex Equipment having Level of Protection "ta" which contains a cell or battery, only a sealed cell or battery shall be used. For Ex Equipment having Level of Protection "tb" and "tc" where there are sparking contacts or hot surfaces, and which contains a cell or battery, only a sealed cell or battery shall be used.

C3 – Table 2 now includes malfunction conditions for temperature class determination of Level of Protection "tb" converter-fed electric machines.

C4 – Annex A added for entry devices with Type of Protection "t" including cable transit devices.

Related directives

Directives related to this standard.


Directive 2014/34/EU Of The European Parliament And Of The Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to equipment and protective systems intended for use in potentially explosive atmospheres (recast)

Life cycle


SRPS EN 60079-31:2015


dnaSRPS EN IEC 60079-31:2024
50.60 Close of voting. Proof returned by secretariat
Dec 3, 2021

Related project

Adopted from EN IEC 60079-31:2024

Adopted from IEC 60079-31:2022 ED3 IDENTICAL

Adopted from IEC 60079-31:2022/COR1:2023 ED3