IEC 60068-2-14:2023

Environmental testing - Part 2-14: Tests - Test N: Change of temperature

IEC 60068-2-14:2023 provides tests with specified ambient temperature changes to analyse their impacts on specimens. This seventh edition cancels and replaces the sixth edition published in 2009. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) updating of the figures for clarification purposes;
b) updating of specimen temperature(s) and severities as well as tolerances for change of temperature tests;
c) revision of standardized requirements for test reports for Tests Na and Nb.

Essais d'environnement - Partie 2-14: Essais - Essai N: Variation de température

L'IEC 60068-2-14:2023 établit les essais de variations de la température ambiante spécifiée pour analyser leurs impacts sur les spécimens. Cette septième édition annule et remplace la sixième édition parue en 2009. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) mise à jour des figures à des fins de clarification;
b) mise à jour des températures et des sévérités des spécimens, ainsi que des tolérances sur les essais de variation de température;
c) révision des exigences normalisées pour les rapports d'essai des Essais Na et Nb.

General Information

• Status: Published
• Publication Date: 26-Jul-2023
• ICS: 19.040 - Environmental testing
• Technical Committee: TC 104 - Environmental conditions, classification and methods of test
• Drafting Committee: MT 16 - TC 104/MT 16
• Current Stage: PPUB - Publication issued
• Start Date: 25-Aug-2023
• Completion Date: 27-Jul-2023

Relations

• Revises: IEC 60068-2-14:2009 - Environmental testing - Part 2-14: Tests - Test N: Change of temperature
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60068-2-14 ®
Edition 7.0 2023-07
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Environmental testing –
Part 2-14: Tests – Test N: Change of temperature

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

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IEC 60068-2-14 ®
Edition 7.0 2023-07
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Environmental testing –
Part 2-14: Tests – Test N: Change of temperature
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 19.040 ISBN 978-2-8322-7338-8

– 2 – IEC 60068-2-14:2023 RLV © IEC 2023
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Symbols . 8
5 General . 8
5.1 Field conditions of changing temperature . 8
5.2 Design of change of temperature tests with temperature change . 9
5.3 Test parameters . 9
5.4 Purpose and choice of the tests . 10
5.5 Choice of the duration of the exposure time to each conditioning
temperature . 10
5.6 Choice of the duration of the transfer time t . 11
5.7 Applicability limits of change of temperature tests . 12
5 Guidance for the selection of the kind of test .
6 Initial and final measurements . 13
6.1 General . 13
6.2 Initial measurements . 13
6.3 Final measurements . 13
7 Test Na: Rapid change of temperature with prescribed time of transfer . 13
7.1 General description of the test . 13
7.2 Testing procedure . 13
7.2.1 Testing chamber . 13
7.2.2 Mounting or supporting of the test specimen . 16
7.2.3 Severities . 16
7.2.4 Conditioning Preconditioning . 18
7.2.5 Test cycle . 18
7.3 Recovery . 21
7.4 Information to be given in the relevant specification .
8 Test Nb: Change of temperature with specified rate of change . 22
8.1 General description of the test . 22
8.2 Testing procedure . 22
8.2.1 Testing chamber . 22
8.2.2 Mounting or supporting structure of the test specimen . 23
8.2.3 Severities . 23
8.2.4 Tolerance . 24
8.2.5 Conditioning Preconditioning . 25
8.3 Test cycle . 25
8.4 Recovery . 27
8.4 Information to be given in the relevant specification .
9 Test Nc: Rapid change of temperature, two-fluid-bath method . 27
9.1 General description of the test . 27
9.2 Testing procedure . 28
9.2.1 Testing equipment . 28
9.2.2 Severities . 28

9.2.3 Conditioning . 28
9.3 Test cycle . 28
9.4 Recovery . 30
9.5 Information to be given in the relevant specification .
10 Information to be given in the test report. 31
Annex A (informative) Potential consequences of improper severities . 33
Annex B (informative) Thermal responsiveness of different materials and geometries . 34
Annex C (normative) Auxiliary table with exemplary temperature tolerances ±σT for
preferred combinations of high and low conditioning temperatures and rates of
temperature change (Test Nb) . 35
Bibliography . 41

Figure 1 – Determination of test duration time (t ) the exposure time t of the specimen
1 1
to each conditioning temperature . 11
Figure 2 – Schematic representation of examples of thermal test cabinets and test
procedure with two separate test chambers . 14
Figure 3 – Schematic representation of examples of thermal test cabinets with one test
chamber . 15
Figure 4 – Possibility of condensation during rapid temperature change . 16
Figure 5 – Possibility of condensation during transfer of the specimen . 16
Figure 6 – Increased severity of Test Na . 17
Figure 2 – Na test cycle .
Figure 7 – Na test cycle, one-chamber method . 19
Figure 8 – Na test cycle, two-chamber method . 21
Figure 9 – Tolerance for fluctuation of test temperatures . 25
Figure 10 – Nb test cycle . 26
Figure 11 – Test times for intermediate operation of specimens . 27
Figure 12 – Nc test cycle . 30
Figure A.1 – Delayed temperature change of the specimen . 33
Figure B.1 – Rate of temperature change of specimen with differing thermal

responsiveness . 34
Figure C.1 – Tolerance for fluctuation of test temperatures for exemplary test
parameters . 36

Table C.1 – Applicable temperature tolerances ±σ in K for preferred combinations of
T
high and low conditioning temperatures and rates of temperature change dT . 37
R
– 4 – IEC 60068-2-14:2023 RLV © IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ENVIRONMENTAL TESTING –
Part 2-14: Tests – Test N: Change of temperature

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...

IEC 60068-2-14 ®
Edition 7.0 2023-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Environmental testing –
Part 2-14: Tests – Test N: Change of temperature

Essais d'environnement –
Partie 2-14: Essais – Essai N: Variation de température
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
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About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
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and withdrawn publications.
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containing more than 22 300 terminological entries in English
details all new publications released. Available online and once
and French, with equivalent terms in 19 additional languages.
a month by email.
Also known as the International Electrotechnical Vocabulary

(IEV) online.
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IEC 60068-2-14 ®
Edition 7.0 2023-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Environmental testing –
Part 2-14: Tests – Test N: Change of temperature

Essais d'environnement –
Partie 2-14: Essais – Essai N: Variation de température

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 19.040  ISBN 978-2-8322-7265-7

– 2 – IEC 60068-2-14:2023 © IEC 2023
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Symbols . 8
5 General . 8
5.1 Field conditions of changing temperature . 8
5.2 Design of tests with temperature change . 9
5.3 Test parameters . 9
5.4 Purpose and choice of the tests . 10
5.5 Choice of the exposure time to each conditioning temperature . 10
5.6 Choice of the duration of the transfer time t . 11
5.7 Applicability limits of change of temperature tests . 11
6 Initial and final measurements . 12
6.1 General . 12
6.2 Initial measurements . 12
6.3 Final measurements . 12
7 Test Na: Rapid change of temperature . 12
7.1 General description of the test . 12
7.2 Testing procedure . 12
7.2.1 Testing chamber . 12
7.2.2 Mounting or supporting of the test specimen . 15
7.2.3 Severities . 15
7.2.4 Preconditioning . 16
7.2.5 Test cycle . 17
7.3 Recovery . 19
8 Test Nb: Change of temperature with specified rate of change . 19
8.1 General description of the test . 19
8.2 Testing procedure . 20
8.2.1 Testing chamber . 20
8.2.2 Mounting or supporting structure of the test specimen . 20
8.2.3 Severities . 20
8.2.4 Tolerance . 21
8.2.5 Preconditioning . 22
8.3 Test cycle . 22
8.4 Recovery . 23
9 Test Nc: Rapid change of temperature, two-fluid-bath method . 24
9.1 General description of the test . 24
9.2 Testing procedure . 24
9.2.1 Testing equipment . 24
9.2.2 Severities . 24
9.2.3 Conditioning . 24
9.3 Test cycle . 25
9.4 Recovery . 25
10 Information to be given in the test report. 26

Annex A (informative) Potential consequences of improper severities . 27
Annex B (informative) Thermal responsiveness of different materials and geometries . 28
Annex C (normative) Auxiliary table with exemplary temperature tolerances ±σ for
T
preferred combinations of high and low conditioning temperatures and rates of
temperature change (Test Nb) . 29
Bibliography . 35

Figure 1 – Determination of the exposure time t of the specimen to each conditioning
temperature . 11
Figure 2 – Schematic representation of examples of thermal test cabinets and test
procedure with two separate test chambers . 13
Figure 3 – Schematic representation of examples of thermal test cabinets with one test
chamber . 14
Figure 4 – Possibility of condensation during rapid temperature change . 15
Figure 5 – Possibility of condensation during transfer of the specimen . 15
Figure 6 – Increased severity of Test Na . 16
Figure 7 – Na test cycle, one-chamber method . 17
Figure 8 – Na test cycle, two-chamber method . 19
Figure 9 – Tolerance for fluctuation of test temperatures . 22
Figure 10 – Nb test cycle . 23
Figure 11 – Test times for intermediate operation of specimens . 23
Figure 12 – Nc test cycle . 25
Figure A.1 – Delayed temperature change of the specimen . 27
Figure B.1 – Rate of temperature change of specimen with differing thermal
responsiveness . 28
Figure C.1 – Tolerance for fluctuation of test temperatures for exemplary test
parameters . 30

Table C.1 – Applicable temperature tolerances ±σ in K for preferred combinations of
T
high and low conditioning temperatures and rates of temperature change dT . 31
R
– 4 – IEC 60068-2-14:2023 © IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
...