Arc welding equipment - Part 8: Gas consoles for welding and plasma cutting systems

IEC 60974-8:2021 is available as IEC 60974-8:2021 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 60974-8:2021 specifies safety and performance requirements for gas consoles intended to be used with combustible gases or oxygen. These gas consoles are designed to supply gases for use in arc welding, plasma cutting, gouging and allied processes in non-explosive atmospheres. The gas console can be external or internal to the power source enclosure. In the latter case, the power source shall meet the requirements of both IEC 60974-1 and this document. This third edition cancels and replaces the second edition, published in 2009. This edition constitutes a technical revision. The significant technical changes with respect to the previous edition are the following:
- changes induced by the publication of IEC 60974-1:2017;
- requirements for the rating plate as in IEC 60974-1:2017, Clause 15;
- requirements for the instructions in 13.2.
This part of IEC 60974 is to be used in conjunction with IEC 60974-1.

Matériel de soudage à l'arc - Partie 8: Consoles de gaz pour soudage et systèmes de coupage par plasma

IEC 60974-8:2021 est disponible sous forme de IEC 60974-8:2021 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.L’IEC 60974-8:2021 spécifie les exigences de performance et de sécurité concernant les consoles de gaz destinées à être utilisées avec des gaz combustibles ou de l’oxygène. Ces consoles de gaz sont conçues pour fournir du gaz qui est utilisé pour le soudage à l’arc, le coupage par plasma, le gougeage et les procédés connexes dans des atmosphères non explosives. Cette troisième édition annule et remplace la deuxième édition, parue en 2009. Cette édition constitue une révision technique. Les modifications techniques majeures par rapport à l'édition précédente sont les suivantes:
- modifications qui résultent de la publication de l’IEC 60974-1:2017;
- exigences relatives à la plaque signalétique comme celles spécifiées à l’Article 15 de l’IEC 60974-1:2017;
- exigences relatives aux instructions en 13.2.
La présente partie de l’IEC 60974 doit être utilisée conjointement avec l’IEC 60974-1.

General Information

Status
Published
Publication Date
22-Apr-2021
Technical Committee
Current Stage
PPUB - Publication issued
Completion Date
23-Apr-2021
Ref Project

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IEC 60974-8
Edition 3.0 2021-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Arc welding equipment –
Part 8: Gas consoles for welding and plasma cutting systems
Matériel de soudage à l’arc –
Partie 8: Consoles de gaz pour soudage et systèmes de coupage par plasma
IEC 60974-8:2021-04(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60974-8
Edition 3.0 2021-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Arc welding equipment –
Part 8: Gas consoles for welding and plasma cutting systems
Matériel de soudage à l’arc –
Partie 8: Consoles de gaz pour soudage et systèmes de coupage par plasma
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.160.30 ISBN 978-2-8322-9705-6

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 60974-8:2021 © IEC 2021
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

3 Terms and definitions ...................................................................................................... 7

4 Environmental conditions ................................................................................................. 9

5 Tests ............................................................................................................................... 9

5.1 Test conditions ....................................................................................................... 9

5.2 Measuring instruments ............................................................................................ 9

5.3 Conformity of components ...................................................................................... 9

5.4 Type tests ............................................................................................................... 9

5.5 Routine tests........................................................................................................... 9

5.5.1 EXTERNAL GAS CONSOLE .................................................................................... 9

5.5.2 INTERNAL GAS CONSOLE ..................................................................................... 9

6 Protection against electric shock ..................................................................................... 9

6.1 Insulation ................................................................................................................ 9

6.1.1 General ........................................................................................................... 9

6.1.2 Clearances .................................................................................................... 10

6.1.3 Creepage distances ....................................................................................... 10

6.1.4 Insulation resistance ...................................................................................... 10

6.1.5 Dielectric strength .......................................................................................... 10

6.2 Protection against electric shock in normal service (direct contact) ....................... 10

6.2.1 Protection provided by the enclosure ............................................................. 10

6.2.2 Capacitors ..................................................................................................... 10

6.2.3 Automatic discharge of supply circuit capacitors ............................................ 10

6.2.4 Isolation of the welding circuit ........................................................................ 10

6.2.5 Welding circuit touch current ......................................................................... 10

6.2.6 Touch current in normal condition .................................................................. 10

6.3 Protection against electric shock in case of a fault condition (indirect

contact) ................................................................................................................ 10

7 Thermal requirements .................................................................................................... 11

7.1 Heating test .......................................................................................................... 11

7.2 Temperature measurement ................................................................................... 11

7.3 Limits of temperature rise ..................................................................................... 11

8 Connections for plasma cutting torches ......................................................................... 11

9 Mechanical provisions ................................................................................................... 11

9.1 General ................................................................................................................. 11

9.2 Protection against fire or explosion ....................................................................... 11

9.3 Gas line purging.................................................................................................... 12

9.4 Enclosure ............................................................................................................. 12

9.4.1 Design requirements ...................................................................................... 12

9.4.2 Enclosure purging .......................................................................................... 12

9.4.3 Safe design of GAS CONSOLE .......................................................................... 13

9.4.4 Open structure ............................................................................................... 13

9.4.5 Solid filled enclosure ..................................................................................... 13

---------------------- Page: 4 ----------------------
IEC 60974-8:2021 © IEC 2021 – 3 –

9.5 EXTERNAL GAS CONSOLE ......................................................................................... 14

9.6 INTERNAL GAS CONSOLE .......................................................................................... 14

10 Gas lines ....................................................................................................................... 14

10.1 Gas hoses and tubing ........................................................................................... 14

10.2 Gas fittings ........................................................................................................... 14

10.3 Leak test ............................................................................................................... 14

11 Control circuits .............................................................................................................. 15

12 Rating plate ................................................................................................................... 15

12.1 EXTERNAL GAS CONSOLE ......................................................................................... 15

12.2 INTERNAL GAS CONSOLE .......................................................................................... 15

13 Instructions and markings .............................................................................................. 15

13.1 General ................................................................................................................. 15

13.2 Instructions ........................................................................................................... 15

13.3 Marking ................................................................................................................. 16

Annex A (informative) Mechanized plasma system diagram ................................................. 17

Annex B (informative) Example of a rating plate layout ........................................................ 18

Bibliography .......................................................................................................................... 19

Figure A.1 – Example of a mechanized plasma system ......................................................... 17

Figure B.1 – Principle of a rating plate .................................................................................. 18

Table 1 – Colour coding ........................................................................................................ 14

---------------------- Page: 5 ----------------------
– 4 – IEC 60974-8:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ARC WELDING EQUIPMENT –
Part 8: Gas consoles for welding and plasma cutting systems
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international

co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and

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Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.

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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent

rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60974-8 has been prepared by IEC technical committee 26: Electric

welding.

This third edition cancels and replaces the second edition, published in 2009. This edition

constitutes a technical revision.

The significant technical changes with respect to the previous edition are the following:

• changes induced by the publication of IEC 60974-1:2017;
• requirements for the rating plate as in IEC 60974-1:2017, Clause 15;
• requirements for the instructions in 13.2.
This part of IEC 60974 is to be used in conjunction with IEC 60974-1.
---------------------- Page: 6 ----------------------
IEC 60974-8:2021 © IEC 2021 – 5 –
The text of this International Standard is based on the following documents:
FDIS Report on voting
26/719/FDIS 26/723/RVD

Full information on the voting for the approval of this International Standard can be found in the

report on voting indicated in the above table.

This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

In this standard, the following print types are used:
– conformity statements: in italic type.
– terms defined in Clause 3: in SMALL ROMAN CAPITALS.

A list of all parts of the IEC 60974 series, published under the general title Arc welding

equipment, can be found on the IEC website.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
---------------------- Page: 7 ----------------------
– 6 – IEC 60974-8:2021 © IEC 2021
INTRODUCTION

If the console is designed to operate with explosive gases, the manufacturer should perform an

assessment for applicability of local legislation for explosive atmospheres (example: ATEX

regulation).
---------------------- Page: 8 ----------------------
IEC 60974-8:2021 © IEC 2021 – 7 –
ARC WELDING EQUIPMENT –
Part 8: Gas consoles for welding and plasma cutting systems
1 Scope

This part of IEC 60974 specifies safety and performance requirements for GAS CONSOLES

intended to be used with combustible gases or oxygen. These GAS CONSOLES are designed to

supply gases for use in arc welding, plasma cutting, gouging and allied processes in non-

explosive atmospheres.

The GAS CONSOLE can be external or internal to the power source enclosure. In the latter case,

the power source shall meet the requirements of both IEC 60974-1 and this document.

NOTE See Annex A for mechanised plasma system diagram.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies.

For undated references, the latest edition of the referenced document (including any

amendments) applies.

IEC 60050-151:2001, International Electrotechnical Vocabulary (IEV) – Part 151: Electrical and

magnetic devices
IEC 60050-151:2001/AMD1:2013
IEC 60050-151:2001/AMD2:2014
IEC 60050-151:2001/AMD3:2019
IEC 60050-151:2001/AMD4:2020
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
IEC 60529:1989/AMD1:1999
IEC 60529:1989/AMD2:2013

IEC 60664-1, Insulation coordination for equipment within low-voltage supply systems – Part 1:

Principles, requirements and tests
IEC 60974-1:2017, Arc welding equipment – Part 1: Welding power sources
IEC 60974-1:2017/AMD1:2019

IEC 60974-10, Arc welding equipment – Part 10: Electromagnetic compatibility (EMC)

requirements

ISO 10225, Gas welding equipment — Marking for equipment used for gas welding, cutting and

allied processes
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 60050-151 and

IEC 60974-1, as well as the following, apply.
---------------------- Page: 9 ----------------------
– 8 – IEC 60974-8:2021 © IEC 2021

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
gas console

device for gas-flow routing, mixing or both that contains electrical apparatus in a single or

multiple enclosure, or open structure
3.2
lower explosion limit
LEL

concentration of flammable gas or vapour in air, below which the gas atmosphere is not

explosive
3.3
lower flammability limit
LFL

minimum concentration of combustible gas in a mixture where a combustion can be ignited by

an ignition source
3.4
upper explosion limit
UEL

concentration of flammable gas or vapour in air, above which the gas atmosphere is not

explosive
3.5
upper flammability limit
UFL

maximum concentration of combustible gas in a mixture where a combustion can be ignited by

an ignition source
3.6
external gas console
GAS CONSOLE not incorporated in a power source
3.7
internal gas console
GAS CONSOLE incorporated in a power source
3.8
single-fault condition
condition in which one means for protection against hazard is defective

Note 1 to entry: If a SINGLE-FAULT CONDITION results unavoidably in another SINGLE-FAULT CONDITION, the two failures

are considered as one SINGLE-FAULT CONDITION.
3.9
hazardous-live-part
live part which, under certain conditions, can give a harmful electric shock
[SOURCE: IEC 60050-195:1998, 195-06-05]
3.10
hazardous part
part that is hazardous to approach or touch
---------------------- Page: 10 ----------------------
IEC 60974-8:2021 © IEC 2021 – 9 –
4 Environmental conditions
As specified in Clause 4 of IEC 60974-1:2017.
5 Tests
5.1 Test conditions
As specified in 5.1 of IEC 60974-1:2017.
5.2 Measuring instruments
As specified in 5.2 of IEC 60974-1:2017.
5.3 Conformity of components
As specified in 5.3 of IEC 60974-1:2017.
5.4 Type tests
As specified in 5.4 of IEC 60974-1:2017.

The other tests included in this document may be carried out in any convenient sequence.

5.5 Routine tests
5.5.1 EXTERNAL GAS CONSOLE

All routine tests shall be carried out on each EXTERNAL GAS CONSOLE in the following sequence:

a) general visual inspection, see 3.1.7 of IEC 60974-1:2017;
b) continuity of protective circuit, see 10.5.3 of IEC 60974-1:2017;
c) dielectric strength, see 6.1.5 of IEC 60974-1:2017;
d) leak test, see 10.3;
e) general visual inspection, see 3.1.7 of IEC 60974-1:2017.
5.5.2 INTERNAL GAS CONSOLE

All routine tests, as specified in 5.5 of IEC 60974-1:2017, shall be carried out on each INTERNAL

GAS CONSOLE, with the following addition:
a) leak test, see 10.3.
6 Protection against electric shock
6.1 Insulation
6.1.1 General
As specified in 6.1.1 of IEC 60974-1:2017, with the following exception:

The micro-environment of printed circuit boards shall be improved to pollution degree 2 or better

(by means such as filtering, coating, potting, moulding) so that only non-conductive pollution or

occasional temporary conductivity caused by condensation occurs in accordance with

IEC 60664-1.
---------------------- Page: 11 ----------------------
– 10 – IEC 60974-8:2021 © IEC 2021
6.1.2 Clearances
As specified in 6.1.2 of IEC 60974-1:2017.
6.1.3 Creepage distances
As specified in 6.1.3 of IEC 60974-1:2017.
6.1.4 Insulation resistance
As specified in 6.1.4 of IEC 60974-1:2017.
6.1.5 Dielectric strength
As specified in 6.1.5 of IEC 60974-1:2017.
6.2 Protection against electric shock in normal service (direct contact)
6.2.1 Protection provided by the enclosure

The minimum degree of protection for GAS CONSOLES shall be IP21S in accordance with

IEC 60529.
Conformity shall be checked by:

a) applying the articulated finger and ball, as specified in IEC 60529, to any openings and

ensuring it does not contact any hazardous live part; and

b) verifying that immediately after the water test, as specified in IEC 60529, the unit satisfies

insulation resistance and the dielectric strength tests and is able to operate.
No power is applied to the unit while performing these tests.
6.2.2 Capacitors
As specified in 6.2.2 of IEC 60974-1:2017.
6.2.3 Automatic discharge of supply circuit capacitors
As specified in 6.2.3 of IEC 60974-1:2017.
6.2.4 Isolation of the welding circuit
As specified in 6.2.4 of IEC 60974-1:2017.
6.2.5 Welding circuit touch current
As specified in 6.2.5 of IEC 60974-1:2017.
6.2.6 Touch current in normal condition
As specified in 6.2.6 of IEC 60974-1:2017.

6.3 Protection against electric shock in case of a fault condition (indirect contact)

As specified in 6.3 of IEC 60974-1:2017.
---------------------- Page: 12 ----------------------
IEC 60974-8:2021 © IEC 2021 – 11 –
7 Thermal requirements
7.1 Heating test
As specified in 7.1 of IEC 60974-1:2017.
7.2 Temperature measurement
As specified in 7.2 of IEC 60974-1:2017.
7.3 Limits of temperature rise
As specified in 7.3 of IEC 60974-1:2017.

Additionally, the temperature of surfaces exposed to combustible gases shall be at least 20 %

cooler than the ignition temperature of any combustible gas intended to be used in the GAS

CONSOLE.

Conformity shall be checked by operating the GAS CONSOLE at the maximum specified ambient

temperature and system duty cycle, while monitoring the inside of the gas console with an IR

camera for temperatures exceeding the 20 % margin of the ignition temperature of any

combustible gas intended to be used in the GAS CONSOLE.

a) with the combinations of gas(es) and flow rates which creates the worst-case condition, as

specified by the manufacturer;
b) with the cooling liquid as specified by the manufacturer.
8 Connections for plasma cutting torches

As specified in 11.4.6 of IEC 60974-1:2017, where the torch connects to the GAS CONSOLE.

9 Mechanical provisions
9.1 General
As specified in Clause 14 of IEC 60974-1:2017, with the following additions.
9.2 Protection against fire or explosion

The GAS CONSOLE shall be designed to prevent fire or explosion under normal operating

conditions and under a SINGLE-FAULT CONDITION (for example, defective valve, hose, etc.).

Where a GAS CONSOLE uses a combustible gas, any circuit, subassembly, or component shall

not be capable of creating temperatures or a spark with sufficient energy to cause an ignition.

A GAS CONSOLE using combustible gas in a mixture shall not allow the concentration of mixture

to be between the LFL and UFL.
Conformity shall be checked by:

a) design evaluation and calculations of the circuits, subassembly, or component verification;

b) applying a fault (for example, open circuit, short circuit, and/or restriction of movement) to

the circuits, subassembly, or component until an event occurs (for example, a spark which

does not cause ignition, fuse opens, unit shuts down, etc.) or a steady-state temperature is

achieved.
---------------------- Page: 13 ----------------------
– 12 – IEC 60974-8:2021 © IEC 2021
9.3 Gas line purging

The GAS CONSOLE shall have a means to purge gas lines when changing to a different type of

gas (for example, oxidizing or oxygen containing to combustible) to reduce the risk of fire or

explosion. In some cases, a small amount of combustible gas or oxygen may accumulate in the

torch. This volume shall be small enough so that no risk can result.

The purging shall occur after each change in gas routing or when the previous gas routing is

unknown.

NOTE 1 A means of accomplishing this can be by purging the lines with a sufficient volume of an inert gas.

NOTE 2 When a risk of fire or explosion exists in the gas lines due to changing gas, the purging can be performed

with the following pressure cycle:
a) reduce the pressure of the GAS CONSOLE circuit to atmosphere pressure;
b) purge the GAS CONSOLE circuit with the purging gas;
c) increase the pressure to the maximum pressure of purging gas;
d) reduce the pressure of the GAS CONSOLE circuit to atmosphere pressure.
Conformity shall be checked by risk analysis and the following test.

The gas lines, when installed with all devices (valves, fittings, etc.) shall be filled with a

combustible gas and measured with a gas detector. Immediately after, the gas lines s

...

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