EN 60068-2-14:2009

SLOVENSKI STANDARD
01-november-2009
1DGRPHãþD
SIST EN 60068-2-14:2002
SIST EN 60068-2-33:2001
Okoljski preskusi - 2-14. del: Preskusi - Preskus N: Temperaturne spremembe (IEC
60068-2-14:2009)
Environmental testing -- Part 2-14: Tests - Test N: Change of temperature
Umgebungseinflüsse -- Teil 2-14: Prüfverfahren - Prüfung N: Temperaturwechsel
Essais d'environnement -- Partie 2-14: Essais - Essai N: Variation de température
Ta slovenski standard je istoveten z: EN 60068-2-14:2009
ICS:
19.040 Preskušanje v zvezi z Environmental testing
okoljem
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 60068-2-14
NORME EUROPÉENNE
July 2009
EUROPÄISCHE NORM
ICS 19.040 Supersedes EN 60068-2-14:1999 and EN 60068-2-33:1999

English version
Environmental testing -
Part 2-14: Tests -
Test N: Change of temperature
(IEC 60068-2-14:2009)
Essais d'environnement -  Umgebungseinflüsse -
Partie 2-14: Essais - Teil 2-14: Prüfverfahren -
Essai N: Variation de température Prüfung N: Temperaturwechsel
(CEI 60068-2-14:2009) (IEC 60068-2-14:2009)

This European Standard was approved by CENELEC on 2009-07-01. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.

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

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: Avenue Marnix 17, B - 1000 Brussels

© 2009 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60068-2-14:2009 E
Foreword
The text of document 104/481/FDIS, future edition 6 of IEC 60068-2-14, prepared by IEC TC 104,
Environmental conditions, classification and methods of test, was submitted to the IEC-CENELEC parallel
vote and was approved by CENELEC as EN 60068-2-14 on 2009-07-01.
This European Standard supersedes EN 60068-2-14:1999 and EN 60068-2-33:1999.
The major changes with regard to EN 60068-2-14:1999 concern:
– merging of EN 60068-2-14:1999 and EN 60068-2-33:1999: Guidance on change of temperature tests;
– updating of the figures, changes to some of the wording and editorial corrections made for clarification.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2010-04-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2012-07-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60068-2-14:2009 was approved by CENELEC as a European
Standard without any modification.
__________
- 3 - EN 60068-2-14:2009
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable for the application 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  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

IEC 60068 Series Environmental testing EN 60068 Series

1) 2)
IEC 60068-2-1 - Environmental testing - EN 60068-2-1 2007
Part 2-1: Tests - Test A: Cold

1) 2)
IEC 60068-2-2 - Environmental testing - EN 60068-2-2 2007
Part 2-2: Tests - Test B: Dry heat

1) 2)
IEC 60068-2-17 - Environmental testing - EN 60068-2-17 1994
Part 2-17: Tests - Test Q: Sealing

1)
IEC Guide 104 - The preparation of safety publications - -
and the use of basic safety publications
and group safety publications
1)
Undated reference.
2)
Valid edition at date of issue.

IEC 60068-2-14
Edition 6.0 2009-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
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
PRICE CODE
INTERNATIONALE
R
CODE PRIX
ICS 19.040 ISBN 2-8318-1022-7
– 2 – 60068-2-14 © IEC:2009
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Normative references .7
3 Field conditions of changing temperature .7
4 General .8
4.1 Design of change of temperature tests .8
4.2 Test parameters .8
4.3 Purpose and choice of the tests .8
4.4 Choice of the duration of the exposure .8
4.5 Choice of the duration of the transfer time.9
4.6 Applicability limits of change of temperature tests .9
5 Guidance for the selection of the kind of test .10
6 Initial and final measurements .10
6.1 Initial measurements .10
6.2 Final measurements .10
7 Test Na: Rapid change of temperature with prescribed time of transfer .10
7.1 General description of the test.10
7.2 Testing procedure .10
7.2.1 Testing chamber.10
7.2.2 Mounting or supporting of the test specimen.11
7.2.3 Severities .11
7.2.4 Conditioning .11
7.2.5 Test cycle.11
7.3 Recovery.12
7.4 Information to be given in the relevant specification .12
8 Test Nb: Change of temperature with specified rate of change .13
8.1 General description of the test.13
8.2 Testing procedure .13
8.2.1 Testing chamber.13
8.2.2 Mounting or supporting of the test specimen.13
8.2.3 Severities .13
8.2.4 Conditioning .14
8.2.5 Test cycle.14
8.3 Recovery.15
8.4 Information to be given in the relevant specification .15
9 Test Nc: Rapid change of temperature, two-fluid-bath method .16
9.1 General description of the test.16
9.2 Testing procedure .16
9.2.1 Testing equipment .16
9.2.2 Severities .16
9.2.3 Conditioning .16
9.3 Test cycle.16
9.4 Recovery.17
9.5 Information to be given in the relevant specification .17

60068-2-14 © IEC:2009 – 3 –
10 Information to be given in the test report .18

Figure 1 – Determination of test duration time (t ).9
Figure 2 – Na test cycle .12
Figure 3 – Nb test cycle .15
Figure 4 – Nc test cycle .17

– 4 – 60068-2-14 © IEC:2009
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ENVIRONMENTAL TESTING –
Part 2-14: Tests – Test N: Change of temperature

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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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 60068-2-14 has been prepared by IEC technical committee 104:
Environmental conditions, classification and methods of test.
This sixth edition cancels and replaces the fifth edition, published in 1984, and its amendment
1 (1986) and constitutes a technical revision.
The major changes with regard to the previous edition concern:
• merging of the previous version of IEC 60068-2-14 with IEC 60068-2-33: Guidance on
change of temperature tests;
• updating of the figures, changes to some of the wording and editorial corrections made for
clarification.
60068-2-14 © IEC:2009 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
104/481/FDIS 104/486/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.
It has the status of a basic safety publication in accordance with IEC Guide 104.
A list of all the parts in the IEC 60068 series, under the general title Environmental testing,
can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site 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.
– 6 – 60068-2-14 © IEC:2009
INTRODUCTION
A change of temperature test is intended to determine the effect on the specimen of a change
of temperature or a succession of changes of temperature.
It is not intended to show effects which are due only to high or low temperatures. For these
effects, the dry heat test or the cold test should be used.
The effect of such tests is determined by
– values of high and low conditioning temperature between which the change is to be
effected,
– the conditioning times for which the test specimen is kept at these temperatures,
– the rate of change between these temperatures,
– the number of cycles of conditioning,
– the amount of heat transfer into or from the specimen.
Guidance on the choice of suitable test parameters for inclusion in the detail specification is
given throughout this standard.

60068-2-14 © IEC:2009 – 7 –
ENVIRONMENTAL TESTING –
Part 2-14: Tests – Test N: Change of temperature

1 Scope
This part of IEC 60068 provides a test to determine the ability of components, equipment or
other articles to withstand rapid changes of ambient temperature. The exposure times
adequate to accomplish this will depend upon the nature of the specimen.
2 Normative references
The following referenced documents are indispensable for the application 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 60068 (all parts), Environmental testing
IEC 60068-2-1, Environmental testing – Part 2-1: Tests – Test A: Cold
IEC 60068-2-2, Environmental testing – Part 2-2: Tests – Test B: Dry heat
IEC 60068-2-17, Environmental testing – Part 2-17: Tests – Test Q: Sealing
IEC Guide 104, The preparation of safety publications and the use of basic safety publications
and group safety publications
3 Field conditions of changing temperature
It is common in electronic equipment and components that changes of temperature occur.
Parts inside equipment undergo slower changes of temperature than those on an external
surface when the equipment is not switched on.
Rapid changes of temperature may be expected
– when equipment is transported from warm indoor environments into cold open air
conditions or vice versa,
– when equipment is suddenly cooled by rainfall or immersion in cold water,
– in externally mounted airborne equipment,
– under certain conditions of transportation and storage.
Components will undergo stresses due to changing temperature when high temperature
gradients build up in an equipment after being switched on, e.g. in the neighbourhood of high
wattage resistors, radiation can cause rise of surface temperature in neighbouring
components while other portions are still cool.
Artificially cooled components may be subjected to rapid temperature changes when the
cooling system is switched on. Rapid changes of temperature in components may also be
induced during manufacturing processes of equipment. Both the number and amplitude of
temperature changes and the time interval between them are important.

– 8 – 60068-2-14 © IEC:2009
4 General
4.1 Design of change of temperature tests
Tests Na, Nb and Nc comprise alternate periods at a high and at a low temperature with well-
defined transfers from one temperature to the other. The conditioning run from laboratory
ambient to the first conditioning temperature, then to the second conditioning temperature,
then back to laboratory ambient is considered one test cycle.
4.2 Test parameters
Test parameters comprise the following:
– laboratory ambient;
– high temperature;
– low temperature;
– duration of exposure;
– transfer time or rate of change;
– number of test cycles.
The high and low temperatures are understood to be ambient temperatures which will be
reached by most specimens with a certain time-lag.
Only in exceptional cases may they be specified outside the normal storage or operating
temperature range of the object under test.
The test is accelerated because the number of severe changes of temperature in a given
period is greater than that which will occur under field conditions.
4.3 Purpose and choice of the tests
Change of temperature testing is recommended in the following cases:
– evaluation of electrical performance during a change of temperature, Test Nb;
– evaluation of mechanical performance during a change of temperature, Test Nb,
– evaluation of electrical
...