CLC IEC/TS 60079-43:2021

SLOVENSKI STANDARD
01-julij-2021
Eksplozivne atmosfere - 43. del: Oprema za neugodne delovne pogoje (IEC/TS
60079-43:2017)
Explosive atmospheres - Part 43: Equipment in adverse service conditions (IEC/TS
60079-43:2017)
Explosionsgefährdete Bereiche - Teil 43: Geräte bei ungünstigen Betriebsbedingungen
(IEC/TS 60079-43:2017)
Atmosphères explosives - Partie 43 : Matériel en conditions de service défavorables
(IEC/TS 60079-43:2017)
Ta slovenski standard je istoveten z: CLC IEC/TS 60079-43:2021
ICS:
29.260.20 Električni aparati za Electrical apparatus for
eksplozivna ozračja explosive atmospheres
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION CLC IEC/TS 60079-43

SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
April 2021
ICS 29.260.20
English Version
Explosive atmospheres - Part 43: Equipment in adverse service
conditions
(IEC/TS 60079-43:2017)
Atmosphères explosives - Partie 43 : Matériel en conditions Explosionsgefährdete Bereiche - Teil 43: Geräte bei
de service défavorables ungünstigen Betriebsbedingungen
(IEC/TS 60079-43:2017) (IEC/TS 60079-43:2017)
This Technical Specification was approved by CENELEC on 2021-04-19.

CENELEC members are required to announce the existence of this TS in the same way as for an EN and to make the TS available promptly
at national level in an appropriate form. It is permissible to keep conflicting national standards in force.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. CLC IEC/TS 60079-43:2021 E

European foreword
This document (CLC IEC/TS 60079-43:2021) consists of the text of IEC TS 60079-43:2017 prepared
by IEC/TC 31 "Equipment for explosive atmospheres".
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Endorsement notice
The text of the International Technical Specification IEC/TS 60079-43:2017 was approved by
CENELEC as a European Technical Specification without any modification.

Annex ZA
(normative)
Normative references to international publications with their
corresponding European publications
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.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is
available here: www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60034-5 - Rotating electrical machines - Part 5: EN IEC 60034-5 -
Degrees of protection provided by the
integral design of rotating electrical
machines (IP code) - Classification
IEC 60068 series Environmental testing EN 60068 series
IEC 60079-0 - Explosive atmospheres - Part 0: EN IEC 60079-0 -
Equipment - General requirements
IEC 60079-11 - Explosive atmospheres - Part 11: EN 60079-11 -
Equipment protection by intrinsic safety "i"
IEC 60079-14 - Explosive atmospheres - Part 14: Electrical EN 60079-14 -
installations design, selection and erection
IEC 60079-17 - Explosive atmospheres - Part 17: Electrical EN 60079-17 -
installations inspection and maintenance
IEC 60529 - Degrees of protection provided by EN 60529 -
enclosures (IP Code)
IEC 60721-1 - Classification of environmental conditions - EN 60721-1 -
Part 1: Environmental parameters and
their severities
IEC 60721-2-1 - Classification of environmental conditions - EN 60721-2-1 -
Part 2-1: Environmental conditions
appearing in nature - Temperature and
humidity
IEC/TR 60721-4 series Classification of environmental conditions - - -

IEC TS 60079-43 ®
Edition 1.0 2017-11
TECHNICAL
SPECIFICATION
Explosive atmospheres –
Part 43: Equipment in adverse service conditions

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.260.20 ISBN 978-2-8322-5011-2

– 2 – IEC TS 60079-43:2017 © IEC 2017
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Environmental conditions affecting the equipment used in explosive atmospheres . 7
4.1 General . 7
4.2 Low temperature effects . 7
4.3 Other environmental effects . 8
5 Recommendations for design of equipment . 8
5.1 General . 8
5.2 Atmospheres containing salt and chlorides . 9
5.3 Snow conditions . 9
5.4 Solar Radiation . 9
5.5 Mechanical integrity . 9
5.6 Icing and winterization . 10
5.7 Impact of rapid cooling . 10
6 Impact of low temperatures on types of protection . 10
6.1 General . 10
6.2 Intrinsic safety "i" . 10
6.3 Flameproof enclosure "d" . 11
6.4 Pressurized enclosure "p" . 11
6.5 Liquid immersion "o" . 11
7 Selection, installation and use of equipment . 11
7.1 Limited functionality . 11
7.2 Cables and cable glands . 11
7.3 Seals and sealing materials . 12
8 Maintenance of equipment . 12
9 Hazardous area classification . 12
Annex A (informative) Recommendations on materials . 13
Annex B (informative) Solar radiation . 14
B.1 General . 14
B.2 Temperature gradients . 14
B.3 Recommendations . 14
B.3.1 Cables and glands . 14
B.3.2 Equipment . 14
B.3.3 Protective measures . 14
Annex C (informative) Electric motors in low temperatures . 15
C.1 General . 15
C.2 Explosion-protection . 15
C.3 Factors that may affect design and performance . 15
Bibliography . 17

IEC TS 60079-43:2017 © IEC 2017 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EXPLOSIVE ATMOSPHERES –
Part 43: Equipment in adverse service conditions

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.
The main task of IEC technical committees is to prepare International Standards. In
exceptional circumstances, a technical committee may propose the publication of a technical
specification when
• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC TS 60079-43, which is a technical specification, has been prepared by IEC Technical
committee 31: Equipment for explosive atmospheres.

– 4 – IEC TS 60079-43:2017 © IEC 2017
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
31/1311/DTS 31/1328A/RVDTS
Full information on the voting for the approval of this technical specification 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.
A list of all parts in the IEC 60079 series, published under the general title Explosive
atmospheres, 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.
A bilingual version of this publication may be issued at a later date.

IEC TS 60079-43:2017 © IEC 2017 – 5 –
INTRODUCTION
IEC 60079-0 specifies the requirements for electrical equipment intended for use in explosive
atmospheres at standard atmospheric conditions:
• temperature –20 °C to +60 °C;
• pressure 80 kPa (0,8 bar) to 110 kPa (1,1 bar); and
• air with normal oxygen content, typically 21 % v/v.
In some cases, other parts of the IEC 60079 series also specify conditions outside the above
range, for example in IEC 60079-1.
IEC 60079-0 states the normal ambient temperature range as –20 °C to +40 °C and states
that electrical equipment designed for use in other than this normal ambient temperature
range is considered to be special and includes additional marking to communicate this to the
user.
IEC 60079-14 includes requirements for users to select and install equipment so that it is
suitable for the environmental conditions, but does not provide any specific guidance for
installations outside of the standard atmospheric conditions or for other adverse
environmental conditions.
Extreme climate conditions in Polar environments are challenging to explosion protection
technology and solutions. Conditions such as snow build-up, icing from spray and freezing of
precipitation can negatively affect the operation and safety of equipment. Extreme low
temperatures and weather conditions make it difficult to process hydrocarbons in open
outdoor process areas and it can also be challenging for equipment operation. Measures to
deal with these challenges are often called 'winterization'.
This document is a guide for equipment subject to adverse service conditions, for example
equipment considered as 'special' in IEC 60079-0. It is applicable to the design, manufacture,
installation, inspection and use of such equipment. Annex A gives recommendations on
materials and Annex C gives information on electric motors in low temperatures. It is possible
that some details in this technical specification will be relocated to relevant parts of the
IEC 60079 series at the next edition of each of those relevant parts as guidance material.
This technical specification does not at this time address other environmental conditions such
as high temperatures, which will be explored further at a later date.

– 6 – IEC TS 60079-43:2017 © IEC 2017
EXPLOSIVE ATMOSPHERES –
Part 43: Equipment in adverse service conditions

1 Scope
This part of IEC 60079, which is a Technical Specification, provides guidance for equipment
for use in explosive atmospheres in environments which may include ambient temperatures
below –20 °С, and additional adverse conditions, including maritime applications.
The purpose of this document is to provide recommendations to be considered for the design,
manufacture and use of equipment. It is intended that this document be used for equipment
operating within the environmental range specified on the certificate for the equipment.
NOTE For detailed classification of climate conditions refer to IEC 60721 series and IEC 60068-1.
This document is intended to be used in conjunction with the IEC 60079 series and the
ISO/IEC 80079 series.
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 60034-5, Rotating electrical machines - Part 5: Degrees of protection provided by the
integral design of rotating electrical machines (IP code) - Classification
IEC 60068 (all parts), Environmental testing
IEC 60079-0, Explosive atmospheres - Part 0: Equipment - General requirements
IEC 60079-11, Explosive atmospheres - Part 11: Equipment protection by intrinsic safety "i"
IEC 60079-14, Explosive atmospheres - Part 14: Electrical installations design, selection and
erection
IEC 60079-17, Explosive atmospheres - Part 17: Electrical installations inspection and
maintenance
IEC 60529, Degrees of protection provided by enclosures (IP Code)
IEC 60721-1, Classification of environmental conditions - Part 1: Environmental parameters
and their severities
IEC 60721-2-1, Classification of environmental conditions - Part 2-1: Environmental conditions
appearing in nature - Temperature and humidity
IEC TR 60721-4 (all parts), Classification of environmental conditions

IEC TS 60079-43:2017 © IEC 2017 – 7 –
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60079-0 apply.
NOTE Additional definitions applicable to explosive atmospheres can be found in IEC 60050-426, International
Electrotechnical Vocabulary – Part 426: Equipment for explosive atmospheres.
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
4 Environmental conditions affecting the equipment used in explosive
atmospheres
4.1 General
For the purposes of this document, the environmental conditions and specific operating
parameters are considered to the extent that they can cause failure of the equipment or its
parts related to explosion protection properties.
Useful information on climate classifications can be found in the IEC 60721 series. These
documents provide for five classifications of Tropical, Arid, Temperate, Cold and Polar. If a
manufacturer wishes to reference equipment as conforming to one of those classifications, it
is recommended the temperatures shown in the specific part of IEC 60721 be used, for
example in establishing the temperatures to be applied for the thermal endurance to heat and
cold tests in IEC 60079-0.
The main environmental factors which may affect the equipment addressed by this document
individually or in combination, include:
– low temperature;
– humidity;
– corrosive media;
– powder snow;
– precipitation;
– spray from waves;
– high winds;
– solar radiation; and
– mechanical effects.
The effect of these factors can be significant, particularly if they arise jointly. Information on
these effects is provided below.
4.2 Low temperature effects
For low temperatures, the following may be relevant and should be considered:
– electrochemical capacitors may freeze and fail;
– battery units may discharge;
– wax and protective compounds may become solid and crack;
– rubber materials may lose elasticity and fail;
– greases may freeze affecting parts such as hinges and shafts;

– 8 – IEC TS 60079-43:2017 © IEC 2017
– relays may malfunction;
– amplifying properties of transistors may decrease;
– loss of ductility or embrittlement of materials or welded joints may occur;
– differential expansion or contraction of materials may have an impact on correct fitting of
components;
– oil viscosity increases, and flow may be restricted or cease, which may c
...