Explosive atmospheres - Part 43: Equipment in adverse service conditions (IEC/TS 60079-43:2017)

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.

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)

Eksplozivne atmosfere - 43. del: Oprema za neugodne delovne pogoje (IEC/TS 60079-43:2017)

General Information

Status
Published
Publication Date
03-Jun-2021
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
28-Apr-2021
Due Date
03-Jul-2021
Completion Date
04-Jun-2021

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SLOVENSKI STANDARD
SIST-TS CLC IEC/TS 60079-43:2021
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
SIST-TS CLC IEC/TS 60079-43:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS CLC IEC/TS 60079-43:2021
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SIST-TS CLC IEC/TS 60079-43:2021
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
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SIST-TS CLC IEC/TS 60079-43:2021
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.
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SIST-TS CLC IEC/TS 60079-43:2021
CLC IEC/TS 60079-43:2021 (E)
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 - - -
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SIST-TS CLC IEC/TS 60079-43:2021
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SIST-TS CLC IEC/TS 60079-43:2021
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

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

® Registered trademark of the International Electrotechnical Commission
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SIST-TS CLC IEC/TS 60079-43:2021
– 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

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SIST-TS CLC IEC/TS 60079-43:2021
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.
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SIST-TS CLC IEC/TS 60079-43:2021
– 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.
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SIST-TS CLC IEC/TS 60079-43:2021
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.
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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
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SIST-TS CLC IEC/TS 60079-43:2021
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;
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SIST-TS CLC IEC/TS 60079-43:2021
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– 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 cause loss of

protection, or failure of mechanical systems;

– oil as dielectric insulation in aged electrical equipment may contain higher water content

which may reduce its dielectric strength or even cause dielectric failure.
4.3 Other environmental effects

High humidity can occur due to changes in temperature, for example, in maritime conditions.

In these cases, the following may be relevant and should be considered:
– dielectric permeability of insulation materials may increase;
– surface resistance of insulation materials may decrease;
– permittivity of air gaps may decrease;

– auxiliary physical-chemical processes in dielectrics and metals may occur, for example

corrosion or biological changes.

These conditions may cause undesirable changes in the capacitance of capacitors, decrease

in insulation resistance, swelling and peeling of dielectrics, metal corrosion, or formation of

mould inside the equipment.

Salt or other contaminants may exacerbate many of the problems that humidity creates, such

as reduced insulating properties and increased corrosion.
5 Recommendations for design of equipment
5.1 General

IEC 60079-0 requires equipment to be constructed in accordance with the applicable safety

requirements of relevant industrial standards. Such standards can include the IEC 60068

series of standards on environmental testing which include some tests relevant to adverse

service conditions. The IEC TR 60721-4 series includes references to relevant tests in the

IEC 60068 series.

Where equipment can be subject to adverse service conditions while in operation, the

manufacturer should supply additional information necessary for the selection, installation,

operation and maintenance of the equipment under those conditions. The upper and lower

values of temperature and humidity should be specified. The recommended values for the

climate classifications are given in IEC 60721-1 and IEC 60721-2-1. Where relevant, the rate

of temperature change for which the equipment is intended should also be specified in the

instructions for the equipment.

NOTE For the same type of equipment, different ranges of temperature are often specified depending on the

specific application.

When storage and transportation conditions before installation exceed the temperature range

covered by the certificate, the potential impact of these temperatures on the Type of

Protection of the equipment should be addressed in the instructions supplied by the

manufacturer. Where such information is not provided in the instructions, it is recommended

that the storage temperatures are not outside the range covered by the certificate.

Types of Protection should remain effective while such equipment is exposed to adverse

service conditions. This will need to be considered during selection and installation, and also

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IEC TS 60079-43:2017 © IEC 2017 – 9 –

considered during inspection and maintenance. Guidance on these aspects is included in

Clauses 7 and 8.

The selection of equipment, design of installations and maintenance should consider the

environmental factors and performance as required by IEC 60079-14 and IEC 60079-17. This

technical specification can also be used to provide additional guidance for these aspects.

5.2 Atmospheres containing salt and chlorides

When equipment is intended for use in areas where it can be exposed to salt mist,

requirements for corrosion resistance due to salt mist should be applied.

NOTE Useful information on classification of chemically active substances and the effect of these substances on

equipment can be found in the IEC 60721-3 series, IEC 60654-4 and ISO 9223.
5.3 Snow conditions

Under powder snow conditions equipment with an ingress protection rating of IP6X,

according to IEC 60529 or IEC 60034-5, is recommended to prevent powder snow entering an

enclosure in a similar way to dust ingress.

Heat dissipating equipment, particularly those with rotating parts, should be protected against

the effect of fallen snow that can melt when the equipment is switched on and re-freeze when

it is switched off. Such equipment should be installed so it is protected against snow or

heated to prevent freezing.
5.4 Solar Radiation

The requirements for the resistance to solar radiation may only need to be applied to parts

which are exposed to solar radiation in working conditions rather than to the whole equipment.

Annex B contains additional information and recommendations regarding solar radiation.

NOTE For equipment with other than white or silver-white surfaces that are subject to solar radiation, the surface

temperatures could rise at least 5K. See Annex B for details.
5.5 Mechanical integrity

At low temperatures, increased requirements for mechanical integrity should be considered.

For equipment, this is addressed during the preparation of a certificate as required by

IEC 60079-0. For installations, this may mean additional requirements, for example mounting

requirements.

NOTE Some grades of steel and cast iron become more brittle at temperatures below -20 °C.

For equipment intended for use in the open air or in rooms (spaces), where the air

temperature and humidity variations do not significantly differ from those in the open air, at a

temperature below -20 °С, the following should be considered:

• In threaded joints, where dissimilar materials with different temperature expansion

coefficients mate, consideration should be given to avoid damage to materials and to

ensure the required tightness when the dimensions of parts change due to the wide range

of temperatures that may be encountered;

• Parts subject to wear, for example as a result of friction, should not wear at a faster rate at

low temperatures compared with wear in temperate climates;
• For parts that may have low impact resilience at low tempera
...

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