IEC 60974-8:2021
(Main)Arc welding equipment - Part 8: Gas consoles for welding and plasma cutting systems
Arc welding equipment - Part 8: Gas consoles for welding and plasma cutting systems
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
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.
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Standards Content (Sample)
IEC 60974-8 ®
Edition 3.0 2021-04
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Arc welding equipment –
Part 8: Gas consoles for welding and plasma cutting systems
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IEC 60974-8 ®
Edition 3.0 2021-04
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Arc welding equipment –
Part 8: Gas consoles for welding and plasma cutting systems
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.160.30 ISBN 978-2-8322-9744-5
– 2 – IEC 60974-8:2021 RLV © IEC 2021
CONTENTS
FOREWORD . 4
INTRODUCTION . 2
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 . 10
6.1 Insulation . 10
6.1.1 General . 10
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 . 11
6.2.6 Touch current in normal condition . 11
6.3 Protection against electric shock in case of a fault condition (indirect
contact) . 11
7 Thermal requirements . 11
7.1 Heating test . 11
7.2 Maximum temperature .
7.2 Temperature measurement . 11
7.3 Limits of temperature rise . 11
8 Connections for plasma cutting torches . 11
9 Mechanical requirements provisions . 12
9.1 General . 12
9.2 Protection against fire or explosion . 12
9.3 Gas line purging. 12
9.4 Enclosure . 13
9.4.1 Design requirements . 13
9.4.2 Enclosure purging . 13
9.4.3 Safe design of GAS CONSOLE . 13
9.4.4 Open structure . 14
9.4.5 Solid filled enclosure . 14
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 . 15
10.3 Leak test . 15
11 Control circuits . 15
12 Rating plate . 15
12.1 EXTERNAL GAS CONSOLE . 16
12.2 INTERNAL GAS CONSOLE . 16
13 Instructions and markings . 16
13.1 General . 16
13.2 Instructions . 16
13.3 Marking . 17
Annex A (informative) Mechanized plasma system diagram . 18
Annex B (informative) Example of a rating plate layout . 19
Bibliography . 20
Figure A.1 – Example of a mechanized plasma system . 18
Figure B.1 – Principle of a rating plate . 19
Table 1 – Colour coding and marking . 15
– 4 – IEC 60974-8:2021 RLV © 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
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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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.
This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition IEC 60974-8:2009. A vertical bar appears in the margin
wherever a change has been made. Additions are in green text, deletions are in
strikethrough red text.
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.
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.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.
– 6 – IEC 60974-8:2021 RLV © 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).
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,
this standard also applies to 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 60974-1:20052017, 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.
– 8 – IEC 60974-8:2021 RLV © 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
[IEV 426-02-09, modified] [1]
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
[IEV 426-02-10, modified]
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.
[IEC 61010-1, definition 3.5.11, modified] [7]
___________
Figures in square brackets refer to the bibliography.
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
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 10.4.25.3 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.
– 10 – IEC 60974-8:2021 RLV © IEC 2021
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:
Printed circuit boards shall be enclosed, coated, or encapsulated.
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.
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 parts 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.
7 Thermal requirements
7.1 Heating test
As specified in 7.1 of IEC 60974-1:2017.
For an external gas console, only the relevant tests are performed.
7.2 Maximum temperature
The temperature at any point shall not exceed the ignition temperature of any combustible gas
intended to be used in the gas console.
Conformity shall be checked by operating the gas console as specified by the manufacturer
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.
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.
– 12 – IEC 60974-8:2021 RLV © IEC 2021
9 Mechanical requirements 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.
Where A GAS CONSOLE uses a combustible gas in a mixture, the mixture shall not be included
within flammability limit that is defined by LFL and UFL.
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;
or
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.
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 shall be
purged according to the instruction manual. Once purging has been completed, the contents of
the gas lines shall be measured with the gas detector to ensure that the lines have been purged
to a level lower than below the lower flammability level (LFL) of the gas. If more than one
combustible gas is used, the test shall be repeated for each combustible gas.
9.4 Enclosure
9.4.1 Design requirements
The GAS CONSOLE (external or internal) shall be designed to withstand or prevent an explosion.
This shall be accomplished by complying with the requirements in 9.4.2, 9.4.3, 9.4.4, or 9.4.5
at least one of the requirements in 9.3.2 through 9.3.4. All tests described below are dangerous,
and shall be performed by a person with sufficient technical knowledge.
NOTE All tests described below are dangerous, and it is recommended that they are performed by qualified
personnel.
9.4.2 Enclosure purging
Purging means typically include positive pressure of an inert gas and forced ventilation (e.g.
use of a non-arcing fan). Any automatic means to purge the GAS CONSOLE enclosure of
combustible gases shall be activated before other electrical devices are energized.
Where a fan or other device is used for purging, a malfunction shall be indicated and the system
shall be prevented from continuing to operate.
After purging, the level of combustible gas shall not exceed the lower explosion level (LEL).
Conformity shall be checked in a draught-free environment by a) or b) below.
a) Simulate a continuous gas leak inside the enclosure equal to the maximum flow rate and
pressure as specified by the manufacturer. Monitor and adjust the gas in the enclosure until
saturation or stabilization occurs. Activate the purging device(s) and monitor the gas to
ensure it reaches the LEL before a potential ignition source is any electrical devices are
energized. Repeat for each type of combustible gas used.
b) Place a simulated arcing device inside the purged enclosure. Monitor and adjust the gas in
the enclosure until saturation or stabilization occurs. Operate all purging means and initiate
start-up sequence. Energize the arcing device to simulate the electronics electrical devices
start-up, and operate continuously ensuring that no ignition occurs. Repeat for each type of
combustible gas used.
NOTE 1 A safe level of gas is 50 % of the LEL.
NOTE 2 The leak rate needs to be considered when performing these tests.
9.4.3 Safe design of GAS CONSOLE
9.4.3.1 Prevention of ignition
The GAS CONSOLE shall be designed to prevent an ignition caused by a gas leak in the enclosure.
Conformity shall be checked by completing the following test.
a) Place the energized equipment, i.e. the EXTERNAL GAS CONSOLE or the power source with
INTERNAL GAS CONSOLE, in a bag (or similar).
b) Simulate a gas leak inside the equipment to create an internal explosive atmosphere.
c) Monitor the mixture until it is halfway between the LEL and the UEL of the gas.
d) Operate the GAS CONSOLE for a period of at least 1 h, during which all components capable
of causing ignition are cycled at least 100 times.
e) Verify that no ignition occurred during the operating period.
f) Ignite the bag (or similar) to confirm that a flammable mixture was present.
– 14 – IEC 60974-8:2021 RLV © IEC 2021
9.4.3.2 Integrity of the enclosure
The enclosure, i.e the EXTERNAL GAS CONSOLE or the power source with INTERNAL GAS CONSOLE,
shall withstand an explosion without degradation of the protective continuity circuit.
Conformity shall be checked by completing the following test.
a) Place the non-energized equipment, i.e. the EXTERNAL GAS CONSOLE or the power source
with INTERNAL GAS CONSOLE, in a bag (or similar).
b) Simulate a gas leak inside the equipment to create an internal explosive atmosphere.
c) Monitor the mixture until it is halfway between the LEL and the UEL of the gas.
d) Ignite the flammable mixture using an arcing device installed in the equipment to create an
explosion.
e) Verify that there was no flying debris.
f) Verify there is no contact with live hazardous parts using the jointed test finger specified in
IEC 60529.
g) Verify the continuity of the protective circuit by visual inspection and measurement.
9.4.4 Open structure
An open-structure GAS CONSOLE designed with no enclosure or a partial enclosure that cannot
accumulate a combustible mixture and cause an explosion shall be considered safe.
Conformity shall be checked by design review.
9.4.5 Solid filled enclosure
A GAS CONSOLE designed with an enclosure that does not contain any empty volume that can
accumulate oxygen or a combustible mixture shall be considered safe.
Conformity shall be checked by design review.
9.5 EXTERNAL GAS CONSOLE
Where combustible gases are used, the EXTERNAL GAS CONSOLE shall only enclose the electric
and non-electric apparatus (for example, electromagnetic valves, metering devices, flow
meters, control circuits) required to route gases to the torch.
Conformity shall be checked by visual inspection.
9.6 INTERNAL GAS CONSOLE
Where combustible gases are used, the INTERNAL GAS CONSOLE gas lines and gas components
shall be separated by a barrier from the power source’s live components hazardous-live-parts
within the same enclosure. GAS CONSOLE control circuits may be located on either side of the
barrier.
Conformity shall be checked by visual inspection.
10 Gas lines
10.1 Gas hoses and tubing
Gas hoses and tubing shall be suitable for the application. Gas hoses and tubing shall be rated
for the maximum pressure at the maximum rated temperature in accordance with the product
ratings.
Supply gas hoses shall be properly colour-coded or marked as specified in Table 1. Where gas
supply circuit conveys more than one type of gas, gas hoses and tubing need not be marked
provided the design prevents misconnections.
Supply gas hoses shall be properly colour-coded as specified in Table 1. If the Letter-code is
used in the supply gas hose, it shall be comply with ISO 10225.
Table 1 – Colour coding and marking
Gas Colour of cover
Acetylene and other combustible gases (except LPG, MPS, natural gas, red methane) Red
Oxygen Blue
Air, nitrogen, argon, CO2 Black
LPG, MPS, natural gas, methane orange Orange
All fuel gases (included in this table) red-orange Red-orange
NOTE 1 The manufacturer should be consulted on the suitability of the hose for use with hydrogen (including the
mixture gases containing hydrogen) or propylene.
NOTE 2 This table is taken from ISO 3821 and ISO 12170 [8].
Conformity shall be checked by visual inspection and the test given in 10.3.
10.2 Gas fittings
Supply gas fittings shall not be interchangeable (for example, size, thread type) to avoid mixing
fuel gases with inert gases or oxygen/air.
Conformity shall be checked by visual inspection.
10.3 Leak test
Assemblies through which gas flows shall be capable of operating under the rated inlet pressure
at the rated operating temperature, without a hazardous leak as specified by the manufacturer.
Conformity shall be checked by a test specified by the manufacturer to ensure a safe assembly.
NOTE Air or inert gas used for this test should not contain contaminants that could degrade
components used with oxygen.
Conformity shall be checked by pressurizing the system to 125 % of the rated pressure using
Nitrogen gas (N2) while ensuring that the leakage is less than or equal to 5 sccm at the rated
inlet pressure and rated operating temperature for 30 s.
11 Control circuits
Control circuits not connected to the welding circuit shall meet the following requirements.
a) The operating voltage of control circuits shall not exceed 250 V.
b) A transformer with separate windings shall be used for supplying the control circuits.
c) Overvoltage protection shall be provided.
d) Overcurrent protection shall be provided.
e) Single-fault conditions that may impair safety shall be evaluated.
f) Transformer secondary, except for SELV, circuits shall be grounded.
– 16 – IEC 60974-8:2021 RLV © IEC 2021
g) Insulation of bundled conductors shall be rated to the highest voltage of any of the
conductors.
h) Software and logic circuits shall not affect safety negatively.
i) Control circuits that leave the enclosure shall be isolated from the primary circuit by
double or reinforced insulation.
NOTE 1 These requirements are based on IEC 60204-1[2].
Conformity shall be checked by measurement or analysis, as appropriate.
NOTE 2 Types of control circuits:
a) control circuits that are internal to the welding/cutting equipment enclosure;
b) control circuits intended for interface between the power source and peripheral equipment designed by the
manufacturer;
c) control circuits intended for interfacing between the power source and other types of ancillary equipment;
d) control circuits intended for inside the gas console.
As specified in Clause 12 of IEC 60974-1:2017.
12 Rating plate
12.1 EXTERNAL GAS CONSOLE
As specified in Clause 15 of IEC 60974-1:2017, with the following modifications (as applicable):
a) type of gas(es) used;
b) maximum inlet gas pressure;
c) maximum gas flow rating for each gas.
See Annex B for an example of a rating plate layout that may be used for an EXTERNAL GAS
CONSOLE.
12.2 INTERNAL GAS CONSOLE
For a GAS CONSOLE within a welding power source enclosure, the rating of the welding power
source specified in Clause 15 of IEC 60974-1:2017, shall be used with the following additions:
a) standard reference;
b) type of gas(es) used;
c) maximum inlet gas pressure;
d) maximum gas flow rating for each gas.
13 Instructions and markings
13.1 General
Each GAS CONSOLE shall be delivered with instructions and markings.
13.2 Instructions
As specified in 17.1 of IEC 60974-1:2017, with the following additions (as applicable):
a) information for selection and connection of gas hoses and I/O cables;
b) EMC information specific to installation and operation of equipment specified in this
standard;
b) EMC classification in accordance with IEC 60974-10 (stand-alone cooling systems only);
c) information regarding gas purging (for example, after each change in gas routing);
d) ventilation requirements for installation;
e) gas flow rates and maximum pressures;
f) information regarding the gas source (for example, types of gas and purity);
g) statement that flashback arrestors are required (unless not available for specific gases or
required pressures) to prevent fire from propagating back to the gas supply;
h) recommended life and replacement of internal flexible hoses for combustible gas and
oxygen;
i) information about contamination of oxygen lines;
j) general information specific to installation and operation of equipment specified in this
standard (e.g. torch location relative to gas console and its supply).
j) how to maintain the gas console, such as recommended cycles for partial and complete test
and other operation;
k) precautions to be taken with gas cylinders.
NOTE The torch used in arc welding, plasma cutting and gouging is an obvious source of ignition necessary for its
intended function.
Conformity shall be checked by visual inspection.
13.3 Marking
As specified in 17.2 of IEC 60974-1:2017, (as applicable) and with the following addition.
Each gas connection shall be legibly and indelibly marked. The gas connections shall be marked
with the maximum pressure and the type(s) of gas(es).
Conformity shall be checked by visual inspection.
– 18 – IEC 60974-8:2021 RLV © IEC 2021
Annex A
(informative)
Mechanized plasma system diagram
Figure A.1 – Example of a mechanized plasma system
Annex B
(informative)
Example of a rating plate layout
Key
1 Name and address of the manufacturer or distributor or importer and optionally a trademark and the country of
origin, if required
2 Reference to this document conforming that the GAS CONSOLE complies with its requirements
3 Type (identification) as given by the manufacturer and traceability of design and manufacturing data, for example,
serial number
4 Type of gases used (for example, H or O )
2 2
5 Rated supply voltage: V
6 Rated maximum supply current: A
7 Maximum inlet gas pressure: MPa (bar)
8 Maximum gas flow rating for each gas: l/min
9 Degree of protection rating: IPXX
Figure B.1 – Principle of a rating plate
– 20 – IEC 60974-8:2021 RLV © IEC 2021
Bibliography
IEC 60050-195:1998, International Electrotechnical Vocabulary (IEV) – Part 195: Earthing and
protection against electric shock
IEC 60050-195:1998/AMD1:2001
IEC 60050-426:20082020, International Electrotechnical Vocabulary (IEV) – Part 426:
Equipment for Explosive atmospheres
IEC 60204-1, Safety of machinery – Electrical equipment of machines – Part 1: General
requirements
IEC 60664-1, Insulation coordination for equipment within low-voltage systems − Part 1:
Principles, requirements and tests
IEC 60974-2, Arc welding equipment – Part 2: Liquid cooling systems
IEC 60974-3, Arc welding equipment – Part 3: Arc striking and stabilizing devices
IEC 60974-7, Arc welding equipment – Part 7: Torches
IEC 61010-1:20012010, Safety requirements for electrical equipment for measurement, control,
and laboratory use – Part 1: General requirements
IEC 61010-1:2010/AMD1:2016
ISO 3821, Gas welding equipment – Rubber hoses for welding, cutting and allied processes
ISO 12170, Gas welding equipment – Thermoplastic hoses for welding and allied processes
___________
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
– 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 .
...
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
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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
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.160.30 ISBN 978-2-8322-9705-6
– 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
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
– 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
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
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preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
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Publications.
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.
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.
– 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).
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.
– 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
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.
– 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.
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;
or
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.
– 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 shall be
purged according to the instruction manual. Once purging has been completed, the contents of
the gas lines shall be measured with the gas detector to ensure that the lines have been purged
to a level below the lower flammability level (LFL) of the gas. If more than one combustible gas
is used, the test shall be repeated for each combustible gas.
9.4 Enclosure
9.4.1 Design requirements
The GAS CONSOLE (external or internal) shall be designed to withstand or prevent an explosion.
This shall be accomplished by complying with the requirements in 9.4.2, 9.4.3, 9.4.4, or 9.4.5.
All tests described below are dangerous, and shall be performed by a person with sufficient
technical knowledge.
9.4.2 Enclosure purging
Purging means typically include positive pressure of an inert gas and forced ventilation (e.g.
use of a non-arcing fan). Any automatic means to purge the GAS CONSOLE enclosure of
combustible gases shall be activated before other electrical devices are energized.
Where a fan or other device is used for purging, a malfunction shall be indicated and the system
shall be prevented from continuing to operate.
After purging, the level of combustible gas shall not exceed the lower explosion level (LEL).
Conformity shall be checked in a draught-free environment by a) or b) below.
a) Simulate a continuous gas leak inside the enclosure equal to the maximum flow rate and
pressure as specified by the manufacturer. Monitor and adjust the gas in the enclosure until
saturation or stabilization occurs. Activate the purging device(s) and monitor the gas to
ensure it reaches the LEL before any electrical devices are energized. Repeat for each type
of combustible gas used.
b) Place a simulated arcing device inside the purged enclosure. Monitor and adjust the gas in
the enclosure until saturation or stabilization occurs. Operate all purging means and initiate
start-up sequence. Energize the arcing device to simulate the electrical devices start-up,
and operate continuously ensuring that no ignition occurs. Repeat for each type of
combustible gas used.
NOTE A safe level of gas is 50 % of the LEL.
9.4.3 Safe design of GAS CONSOLE
9.4.3.1 Prevention of ignition
The GAS CONSOLE shall be designed to prevent an ignition caused by a gas leak in the enclosure.
Conformity shall be checked by completing the following test.
a) Place the energized equipment, i.e. the EXTERNAL GAS CONSOLE or the power source with
INTERNAL GAS CONSOLE, in a bag (or similar).
b) Simulate a gas leak inside the equipment to create an internal explosive atmosphere.
c) Monitor the mixture until it is halfway between the LEL and the UEL of the gas.
d) Operate the GAS CONSOLE for a period of at least 1 h, during which all components capable
of causing ignition are cycled at least 100 times.
e) Verify that no ignition occurred during the operating period.
9.4.3.2 Integrity of the enclosure
The enclosure, i.e the EXTERNAL GAS CONSOLE or the power source with INTERNAL GAS CONSOLE,
shall withstand an explosion without degradation of the protective continuity circuit.
Conformity shall be checked by completing the following test.
a) Place the non-energized equipment, i.e. the EXTERNAL GAS CONSOLE or the power source
with INTERNAL GAS CONSOLE, in a bag (or similar).
b) Simulate a gas leak inside the equipment to create an internal explosive atmosphere.
c) Monitor the mixture until it is halfway between the LEL and the UEL of the gas.
d) Ignite the flammable mixture using an arcing device installed in the equipment to create an
explosion.
e) Verify that there was no flying debris.
f) Verify there is no contact with hazardous parts using the jointed test finger specified in
IEC 60529.
g) Verify the continuity of the protective circuit by visual inspection and measurement.
9.4.4 Open structure
An open-structure GAS CONSOLE designed with no enclosure or a partial enclosure that cannot
accumulate a combustible mixture and cause an explosion shall be considered safe.
Conformity shall be checked by design review.
9.4.5 Solid filled enclosure
A GAS CONSOLE designed with an enclosure that does not contain any empty volume that can
accumulate oxygen or a combustible mixture shall be considered safe.
Conformity shall be checked by design review.
– 14 – IEC 60974-8:2021 © IEC 2021
9.5 EXTERNAL GAS CONSOLE
Where combustible gases are used, the EXTERNAL GAS CONSOLE shall only enclose the electric
and non-electric apparatus (for example, electromagnetic valves, metering devices, flow
meters, control circuits) required to route gases to the torch.
Conformity shall be checked by visual inspection.
9.6 INTERNAL GAS CONSOLE
Where combustible gases are used, the INTERNAL GAS CONSOLE gas lines and gas components
shall be separated by a barrier from the power source’s hazardous-live-parts within the same
enclosure. GAS CONSOLE control circuits may be located on either side of the barrier.
Conformity shall be checked by visual inspection.
10 Gas lines
10.1 Gas hoses and tubing
Gas hoses and tubing shall be suitable for the application. Gas hoses and tubing shall be rated
for the maximum pressure at the maximum rated temperature in accordance with the product
ratings.
Supply gas hoses shall be properly colour-coded as specified in Table 1. If the Letter-code is
used in the supply gas hose, it shall be comply with ISO 10225.
Table 1 – Colour coding
Gas Colour of cover
Acetylene and other combustible gases (except LPG, MPS, natural gas, methane) Red
Oxygen Blue
Air, nitrogen, argon, CO2 Black
LPG, MPS, natural gas, methane Orange
All fuel gases (included in this table) Red-orange
NOTE 1 The manufacturer should be consulted on the suitability of the hose for use with hydrogen (including the
mixture gases containing hydrogen) or propylene.
NOTE 2 This table is taken from ISO 3821 and ISO 12170.
Conformity shall be checked by visual inspection and the test given in 10.3.
10.2 Gas fittings
Supply gas fittings shall not be interchangeable (for example, size, thread type) to avoid mixing
fuel gases with inert gases or oxygen/air.
Conformity shall be checked by visual inspection.
10.3 Leak test
Assemblies through which gas flows shall be capable of operating under the rated inlet pressure
at the rated operating temperature, without a hazardous leak. Air or inert gas used for this test
should not contain contaminants that could degrade components used with oxygen.
Conformity shall be checked by pressurizing the system to 125 % of the rated pressure using
Nitrogen gas (N2) while ensuring that the leakage is less than or equal to 5 sccm at the rated
inlet pressure and rated operating temperature for 30 s.
11 Control circuits
As specified in Clause 12 of IEC 60974-1:2017.
12 Rating plate
12.1 EXTERNAL GAS CONSOLE
As specified in Clause 15 of IEC 60974-1:2017, with the following modifications (as applicable):
a) type of gas(es) used;
b) maximum inlet gas pressure;
c) maximum gas flow rating for each gas.
See Annex B for an example of a rating plate layout that may be used for an EXTERNAL GAS
CONSOLE.
12.2 INTERNAL GAS CONSOLE
For a GAS CONSOLE within a welding power source enclosure, the rating of the welding power
source specified in Clause 15 of IEC 60974-1:2017, shall be used with the following additions:
a) standard reference;
b) type of gas(es) used;
c) maximum inlet gas pressure;
d) maximum gas flow rating for each gas.
13 Instructions and markings
13.1 General
GAS CONSOLE shall be delivered with instructions and markings.
Each
13.2 Instructions
As specified in 17.1 of IEC 60974-1:2017, with the following additions (as applicable):
a) information for selection and connection of gas hoses and I/O cables;
b) EMC classification in accordance with IEC 60974-10 (stand-alone cooling systems only);
c) information regarding gas purging (for example, after each change in gas routing);
d) ventilation requirements for installation;
e) gas flow rates and maximum pressures;
f) information regarding the gas source (for example, types of gas and purity);
g) statement that flashback arrestors are required (unless not available for specific gases or
required pressures) to prevent fire from propagating back to the gas supply;
h) recommended life and replacement of internal flexible hoses for combustible gas and
oxygen;
i) information about contamination of oxygen lines;
– 16 – IEC 60974-8:2021 © IEC 2021
j) how to maintain the gas console, such as recommended cycles for partial and complete test
and other operation;
k) precautions to be taken with gas cylinders.
NOTE The torch used in arc welding, plasma cutting and gouging is an obvious source of ignition necessary for its
intended function.
Conformity shall be checked by visual inspection.
13.3 Marking
As specified in 17.2 of IEC 60974-1:2017, (as applicable) and with the following addition.
Each gas connection shall be legibly and indelibly marked. The gas connections shall be marked
with the maximum pressure and the type(s) of gas(es).
Conformity shall be checked by visual inspection.
Annex A
(informative)
Mechanized plasma system diagram
Figure A.1 – Example of a mechanized plasma system
– 18 – IEC 60974-8:2021 © IEC 2021
Annex B
(informative)
Example of a rating plate layout
Key
1 Name and address of the manufacturer or distributor or importer and optionally a trademark and the country of
origin, if required
2 Reference to this document conforming that the GAS CONSOLE complies with its requirements
3 Type (identification) as given by the manufacturer and traceability of design and manufacturing data, for example,
serial number
4 Type of gases used (for example, H or O )
2 2
5 Rated supply voltage: V
6 Rated maximum supply current: A
7 Maximum inlet gas pressure: MPa (bar)
8 Maximum gas flow rating for each gas: l/min
9 Degree of protection rating: IPXX
Figure B.1 – Principle of a rating plate
Bibliography
IEC 60050-195:1998, International Electrotechnical Vocabulary (IEV) – Part 195: Earthing and
protection against electric shock
IEC 60050-195:1998/AMD1:2001
IEC 60050-426:2020, International Electrotechnical Vocabulary (IEV) – Part 426: Explosive
atmospheres
IEC 60204-1, Safety of machinery – Electrical equipment of machines – Part 1: General
requirements
IEC 60974-2, Arc welding equipment – Part 2: Liquid cooling systems
IEC 60974-3, Arc welding equipment – Part 3: Arc striking and stabilizing devices
IEC 60974-7, Arc welding equipment – Part 7: Torches
IEC 61010-1:2010, Safety requirements for electrical equipment for measurement, control, and
laboratory use – Part 1: General requirements
IEC 61010-1:2010/AMD1:2016
ISO 3821, Gas welding equipment – Rubber hoses for welding, cutting and allied processes
ISO 12170, Gas welding equipment – Thermoplastic hoses for welding and allied processes
___________
– 20 – IEC 60974-8:2021 © IEC 2021
SOMMAIRE
AVANT-PROPOS . 22
INTRODUCTION . 24
1 Domaine d’application . 25
2 Références normatives . 25
3 Termes et définitions . 26
4 Conditions ambiantes . 27
5 Essais . 27
5.1 Conditions d’essai . 27
5.2 Instruments de mesure . 27
5.3 Conformité des composants . 27
5.4 Essais de type . 27
5.5 Essais individuels de série . 27
5.5.1 CONSOLE DE GAZ EXTERNE . 27
5.5.2 CONSOLE DE GAZ INTERNE . 27
6 Protection contre les chocs électriques . 28
6.1 Isolement . 28
6.1.1 Généralités . 28
6.1.2 Distances d’isolement dans l’air . 28
6.1.3 Lignes de fuite . 28
6.1.4 Résistance d’isolement . 28
6.1.5 Rigidité diélectrique . 28
6.2 Protection contre les chocs électriques en service normal (contact direct) . 28
6.2.1 Degré de protection procuré par l’enveloppe . 28
6.2.2 Condensateurs . 28
6.2.3 Décharge automatique des condensateurs sur le circuit d’alimentation . 28
6.2.4 Isolation du circuit de soudage . 28
6.2.5 Courant de contact d’un circuit de soudage . 29
6.2.6 Courant de contact en condition normale . 29
6.3 Protection contre les chocs
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