Explosive atmospheres - Part 5: Equipment protection by powder filling "q"

IEC 60079-5:2015 is available as IEC 60079-5:2015 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 60079-5:2015 contains specific requirements for the construction, testing and marking of electrical equipment, parts of electrical equipment and Ex components in the type of protection powder filling "q", intended for use in explosive gas atmospheres. This standard supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of this standard takes precedence. This standard applies to electrical equipment, parts of electrical equipment and Ex components with:
- a rated supply current less than or equal to 16 A;
- a rated supply voltage less than or equal to 1 000 V;
- a rated power consumption less than or equal to 1 000 W. This fourth edition cancels and replaces the third edition, published in 2007, and constitutes a technical revision. Refer to the Foreword of the document for a complete listing of the technical changes between edition 4.0 and previous edition of the document. Keywords: electrical equipment and Ex components in the type of protection powder filling "q"

Atmosphères explosives - Partie 5: Protection du matériel par remplissage pulvérulent "q"

IEC 60079-5:2015 est disponible sous forme de IEC 60079-5:2015 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.
IEC 60079-5:2015 contient les exigences spécifiques de construction, d'essais et de marquage d'appareil électrique, des parties d'appareil électrique et des composants Ex à remplissage pulvérulent, mode de protection "q", destinés à être utilisés dans des atmosphères explosives gazeuses. La présente norme complète et modifie les exigences générales de l'IEC 60079-0. Lorsqu'une exigence de la présente norme diverge d'une exigence de l'IEC 60079-0, l'exigence de cette norme prévaut. La présente norme s'applique aux appareils électriques, aux parties d'appareil électrique et aux composants Ex avec:
- un courant assigné d'alimentation inférieur ou égal à 16 A;
- une tension assignée d'alimentation inférieure ou égale à 1 000 V;
- une puissance consommée assignée inférieure ou égale à 1 000 W. Cette quatrième édition annule et remplace la troisième édition parue en 2007. Cette édition constitue une révision technique. Reportez-vous à l'avant-propos du document pour une liste complète des modifications techniques entre l'édition 4.0 et édition précédente du document. Mots clés: d'appareil électrique et des composants Ex à remplissage pulvérulent, mode de protection "q"

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Status
Published
Publication Date
16-Feb-2015
Current Stage
PPUB - Publication issued
Start Date
17-Feb-2015
Completion Date
17-Feb-2015
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IEC 60079-5
Edition 4.0 2015-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Explosive atmospheres –
Part 5: Equipment protection by powder filling “q”
Atmosphères explosives –
Partie 5: Protection du matériel par remplissage pulvérulent “q”
IEC 60079-5:2015-02(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60079-5
Edition 4.0 2015-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Explosive atmospheres –
Part 5: Equipment protection by powder filling “q”
Atmosphères explosives –
Partie 5: Protection du matériel par remplissage pulvérulent “q”
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.260.20 ISBN 978-2-8322-2249-2

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 60079-5:2015 © IEC 2015
CONTENTS

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

1 Scope ............................................................................................................................ 6

2 Normative references..................................................................................................... 6

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

4 Constructional requirements .......................................................................................... 7

4.1 Containers ............................................................................................................ 7

4.1.1 Closing and sealing ........................................................................................ 7

4.1.2 Pressure test of container .............................................................................. 8

4.1.3 Degree of protection of the container .............................................................. 8

4.1.4 Filling procedure ............................................................................................ 8

4.1.5 Containers that are not external enclosures .................................................... 8

4.2 Filling material ...................................................................................................... 9

4.2.1 Material specification ..................................................................................... 9

4.2.2 Documentation ............................................................................................... 9

4.2.3 Testing .......................................................................................................... 9

4.3 Distances .............................................................................................................. 9

4.3.1 Distances through filling material .................................................................... 9

4.3.2 Distances surrounding free space ................................................................. 11

4.4 Connections ........................................................................................................ 12

4.4.1 Equipment ................................................................................................... 12

4.4.2 Ex Components ........................................................................................... 12

4.5 Capacitors .......................................................................................................... 12

4.6 Cells and batteries .............................................................................................. 12

4.7 Temperature limitations under overload conditions ............................................... 12

4.8 Temperature limitations under malfunction conditions .......................................... 12

4.8.1 General ....................................................................................................... 12

4.8.2 Fuse ............................................................................................................ 12

4.8.3 Malfunction exclusions ................................................................................. 13

4.8.4 Protective devices for temperature limitation ................................................. 16

4.8.5 Power supply prospective short-circuit current .............................................. 16

5 Verifications and tests ................................................................................................. 16

5.1 Type verifications and tests ................................................................................. 16

5.1.1 Pressure type test of container ..................................................................... 16

5.1.2 Verification of the degree of protection of the enclosure ................................ 17

5.1.3 Dielectric strength test of the filling material ................................................. 17

5.1.4 Maximum temperatures ................................................................................ 17

5.2 Routine verifications and tests ............................................................................. 18

5.2.1 Routine pressure test of container ................................................................ 18

5.2.2 Dielectric strength test of the filling material ................................................. 18

6 Marking ....................................................................................................................... 19

7 Instructions.................................................................................................................. 20

Bibliography ....................................................................................................................... 21

---------------------- Page: 4 ----------------------
IEC 60079-5:2015 © IEC 2015 – 3 –

Figure 1 – Distances through filling material ........................................................................ 11

Figure 2 – Test arrangement for the dielectric strength test of the filling material ................. 19

Table 1 – Distances through the filling material.................................................................... 10

Table 2 – Creepage distances and distances through filling material .................................... 15

---------------------- Page: 5 ----------------------
– 4 – IEC 60079-5:2015 © IEC 2015
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EXPLOSIVE ATMOSPHERES –
Part 5: Equipment protection by powder filling “q”
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, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC

Publication(s)”). Their 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

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence

between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in

the latter.

5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

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

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

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 60079-5 has been prepared by IEC technical committee 31:

Equipment for explosive atmospheres.

This fourth edition cancels and replaces the third edition, published in 2007, and constitutes a

technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:

NOTE The technical changes referred to include the significant technical changes in the revised IEC standard, but

they do not form an exhaustive list of all modifications from the previous edition. More guidance may be found by

referring to the redline version of the IEC standard, if available.
---------------------- Page: 6 ----------------------
IEC 60079-5:2015 © IEC 2015 – 5 –
Type
Significant changes Clause/subclause Minor and Extension Major
editorial technical
changes changes
Specific references to IEC 60079-0 have been
4.1.3 4.8 4.8.3 X
reworded so the references to IEC 60079-0 can
be non-dated references
The “housing” surrounding the powder filled
equipment or Ex Component has been
redefined as a “container” to avoid confusion 4.1 X
with the “enclosure” requirements of
IEC 60079-0
A relaxation has been introduced to permit
reduced distances through filling material for
4.3.1 X
instances where there is no adjacent gap in the
container
A relaxation has been introduced to permit the
use of creepage dimensions per IEC 60079-7 4.8.3 X
where CTI is better than 175
An evaluation of joints employed when the
5.1.1 X
reduced distances according to Table 1 are
applied, has been added.
Text for determination of maximum temperature
clarified with respect to overloads and 5.1.4 X
malfunctions
A batch routine test has been introduced 5.2.1 X
The text of this standard is based on the following documents:
FDIS Report on voting
31/1156/FDIS 31/1171/RVD

Full information on the voting for the approval of this standard can be found in the report on

voting indicated in the above table.

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

The list of all parts of IEC 60079 series, under the general title Explosive atmospheres, can

be found on the IEC website.

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

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

related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
---------------------- Page: 7 ----------------------
– 6 – IEC 60079-5:2015 © IEC 2015
EXPLOSIVE ATMOSPHERES –
Part 5: Equipment protection by powder filling “q”
1 Scope

This part of IEC 60079 contains specific requirements for the construction, testing and

marking of electrical equipment, parts of electrical equipment and Ex components in the type

of protection powder filling “q”, intended for use in explosive gas atmospheres.

NOTE 1 Electrical equipment and Ex components protected by powder filling “q” can contain electronic circuits,

transformers, protection fuses, relays, intrinsically safe electrical apparatus, associated electrical apparatus,

switches, etc.

NOTE 2 Type of protection powder filling “q” provides Equipment Protection Level (EPL) Gb or Mb.

This standard supplements and modifies the general requirements of IEC 60079-0. Where a

requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of

this standard takes precedence.

This standard applies to electrical equipment, parts of electrical equipment and Ex

components with:
– a rated supply current less than or equal to 16 A;
– a rated supply voltage less than or equal to 1 000 V;
– a rated power consumption less than or equal to 1 000 W.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and

are indispensable for its application. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60079-0, Explosive atmospheres – Part 0: Equipment – General requirements

IEC 60079-7, Explosive atmospheres – Part 7: Equipment protection by increased safety "e"

IEC 60079-11, Explosive atmospheres – Part 11: Equipment protection by intrinsic safety "i"

IEC 60127 (all parts), Miniature fuses
IEC 60529, Degrees of protection provided by enclosures (IP Code)

IEC 61558-1, Safety of power transformers, power supplies, reactors and similar products –

Part 1: General requirements and tests

IEC 61558-2-6, Safety of transformers, reactors, power supply units and similar products for

supply voltages up to 1 100 V – Part 2-6: Particular requirements and tests for safety isolating

transformers and power supply units incorporating safety isolating transformers

ISO 2859-1, Sampling procedures for inspection by attributes – Part 1: Sampling schemes

indexed by acceptance quality limit (AQL) for lot-by-lot inspection
---------------------- Page: 8 ----------------------
IEC 60079-5:2015 © IEC 2015 – 7 –

ISO 3310-1, Test sieves – Technical requirements and testing – Part 1: Test sieves of metal

wire cloth

ISO 3310-2, Test sieves – Technical requirements and testing – Part 2: Test sieves of

perforated metal plate

ISO 2591-1, Test sieving – Methods using test sieves of woven wire cloth and perforated

metal plate
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 60079-0 as well as

the following apply.

NOTE Additional definitions applicable to explosive atmospheres can be found in IEC 60050-426.

3.1
powder filling “q”

type of protection in which the parts capable of igniting an explosive gas atmosphere are fixed

in position and completely surrounded by filling material to prevent the ignition of an external

explosive gas atmosphere

Note 1 to entry: The type of protection may not prevent the surrounding explosive gas atmosphere from

penetrating into the equipment and components and being ignited by the circuits. However, due to the small free

volumes in the filling material and due to the quenching of a flame which may propagate through the paths in the

filling material, an external explosion is prevented.
3.2
filling material
solid quartz or solid glass particles
3.3
container (for filling material)

housing immediately surrounding the electrical equipment protected by and containing the

filling material

Note 1 to entry: The container may, in some cases, also be the external enclosure.

4 Constructional requirements
4.1 Containers
4.1.1 Closing and sealing
4.1.1.1 General

Containers of electrical equipment, parts of electrical equipment or Ex components protected

by powder filling ”q” shall be filled and sealed at the time of manufacture. The closing and

sealing shall be the methods of 4.1.1.2 or 4.1.1.3.
4.1.1.2 Containers permanently sealed at the time of manufacture

The container shall be permanently sealed at the time of manufacture and shall not be

capable of being opened without leaving visible evidence that the container has been opened.

The container shall be marked in accordance with Clause 6, item a).

NOTE Suitable techniques that can provide visible evidence of containers being opened are, for example,

welding, soldering, cemented joints, rivets, cementing of screws, or lead-seal safety-wiring of screws.

---------------------- Page: 9 ----------------------
– 8 – IEC 60079-5:2015 © IEC 2015
4.1.1.3 Containers intended to be opened for repair

Electrical equipment, parts of electrical equipment, or Ex components that are designed to be

repaired shall incorporate sealing methods that are capable of being renewed without damage

to the container when the equipment is repaired, re-filled, and re-sealed. The container shall

be marked in accordance with Clause 6, item b).
4.1.2 Pressure test of container

The electrical equipment, parts of electrical equipment or Ex components protected by powder

filling “q” shall meet the pressure test requirements specified in 5.1.1.
4.1.3 Degree of protection of the container

The container of the electrical equipment, parts of electrical equipment, or Ex components

protected by powder filling “q”, in their normal service condition, i.e. with all openings closed

as in normal use, shall comply at least with the degree of protection IP54 as defined in

IEC 60529. If the degree of protection is IP55 or higher, and the container is not hermetically

sealed, the container shall be provided with a breathing device. The container with the

breathing device in place shall comply at least with the degree of protection IP54 according to

IEC 60529. The test shall be conducted on an empty container without the powder filling

installed. At the end of any water ingress tests, no water shall be visible inside the container.

NOTE 1 As the container may need to be destroyed in order to determine the entrance of dust or water, two

separate test samples could be required for the two ingress tests.

NOTE 2 When the container is also the external enclosure, the tests of enclosures requirements of IEC 60079-0

apply.

The ingress protection of containers or parts of electrical equipment protected by powder

filling “q”, intended for use only in clean, dry rooms, may be reduced to degree of protection

IP43. The certificate number of this equipment shall include the "X" suffix in accordance with

the marking requirements of IEC 60079-0, and the Specific Conditions of Use listed on the

certificate shall detail the restrictions of use.

When Ex components protected by powder filling “q” are intended to be mounted inside

another enclosure complying with IEC 60079-0, this outer enclosure shall have a degree of

protection of at least IP54. The IP rating of the inner container does not need to be specified

provided that the Ex component is mounted in a position where it is unlikely to be

contaminated by any small amounts of water that may enter the outer enclosure.

NOTE 3 The impact and drop tests of enclosures from IEC 60079-0 do not generally apply to Ex Components

intended to be mounted inside another enclosure complying with IEC 60079-0, as the external enclosure provides

the protection against impact and drop.

The maximum gap of a container protected by powder filling “q” shall be at least 0,1 mm

smaller than the specified smallest dimension of the filling material.

NOTE 4 The restriction on the size of the gap is intended to reduce the escape of filling material.

4.1.4 Filling procedure

Filling shall be carried out so as not to leave any void within the filling material (for example

by shaking down). The free space within electrical equipment, parts of electrical equipment or

Ex components protected by powder filling “q” shall be effectively filled with filling material

(see also 4.3.2).
4.1.5 Containers that are not external enclosures

The container of type of protection “q” equipment or Ex Component that is installed or

intended to be installed internal to another enclosure is considered the same as that of an Ex

Component.
---------------------- Page: 10 ----------------------
IEC 60079-5:2015 © IEC 2015 – 9 –
4.2 Filling material
4.2.1 Material specification
The material shall be quartz or solid glass particles.

The material specification shall state that, determined in accordance with the ISO 2591-1

procedure for dry materials, the size of particles are within the following sieve sizes:

– 1 mm nominal aperture sieve in accordance with ISO 3310-1 or ISO 3310-2
– 500 µm nominal aperture sieve in accordance with ISO 3310-1.
4.2.2 Documentation

The documents prepared by the manufacturer in accordance with IEC 60079-0 shall include

the specification of the particle material, the size range of the particles, as well as the filling

process and the measures taken to ensure proper filling.

NOTE It is not a requirement of this standard that conformity to the specification of the particle material and size

range of the particles needs to be verified.
4.2.3 Testing

The filling material shall be subjected to the dielectric strength test specified in 5.1.3.

4.3 Distances
4.3.1 Distances through filling material

Except where specified otherwise in this standard, the minimum distance through the filling

material between electrically conducting parts of the equipment and the container shall

comply with Table 1 and Figure 1. This does not apply to conductors used for field wiring

connections which penetrate the wall of the container.
---------------------- Page: 11 ----------------------
– 10 – IEC 60079-5:2015 © IEC 2015
Table 1 – Distances through the filling material
a b
Voltage a.c. r.m.s. or d.c. Minimum distance Reduced distance
V mm mm
5 1,5
U ≤ 80
5 2
U ≤ 100
U ≤125 5 2
5 2
U ≤ 160
5 3
U ≤ 200
U ≤ 250 5 3
U ≤ 400 6,3 3
8 3
U ≤ 500
U ≤ 800 10 5
U ≤ 1 000 14 5
16 10
U ≤ 1 600
25 10
U ≤ 2 500
U ≤ 3 200 32 10
40 14
U ≤ 4 000
50 14
U ≤ 5 000
U ≤ 6 300 63 25
U ≤ 8 000 80 25
100 40
U ≤ 10 000

When determining the required values for creepage and distance, the working voltage may be higher than

the voltage in the table by a factor of 1,1 (see Note).

NOTE The factor of 1,1 recognizes that at many places in a circuit, the working voltage equals the rated

voltage and that there are a number of rated voltages in common use that can be accommodated by the 1,1

factor.

To ensure that there is a sufficient path length through the filling material to provide quenching of a flame

from the inside to the outside of the container, the reduced distances shown are permitted only when there

is no adjacent gap in the container that could permit a flame to exit. See Figure 1.

---------------------- Page: 12 ----------------------
IEC 60079-5:2015 © IEC 2015 – 11 –
top
conductive (metallic) wall
gap
gap
solid
insulation
non-conductive non-conductive
wall wall
a d
conductive (metallic) wall
gap
bottom
IEC
Key
distance to cond
...

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