IEC 60068-2-38:2009

IEC 60068-2-38
Edition 2.0 2009-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
Environmental testing –
Part 2-38: Tests – Test Z/AD: Composite temperature/humidity cyclic test

Essais d’environnement –
Partie 2-38: Essais – Essai Z/AD: Essai cyclique composite de température et
d’humidité
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IEC 60068-2-38
Edition 2.0 2009-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
Environmental testing –
Part 2-38: Tests – Test Z/AD: Composite temperature/humidity cyclic test

Essais d’environnement –
Partie 2-38: Essais – Essai Z/AD: Essai cyclique composite de température et
d’humidité
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
N
CODE PRIX
ICS 19.040 ISBN 978-2-88910-038-5
– 2 – 60068-2-38 © IEC:2009
CONTENTS
FOREWORD.3
1 Scope.5
2 Normative references .5
3 General .5
3.1 Description of the test .5
3.2 Application of the test.6
4 Description of test chamber .6
4.1 Chamber for exposure to moisture.6
4.2 Chamber for exposure to cold.7
5 Severities .7
6 Testing procedure .7
6.1 Preconditioning (see figure 1).7
6.2 Initial measurements .8
6.3 Conditioning .8
6.4 Test cycle.12
6.4.1 Description of temperature/humidity subcycle .12
6.4.2 Description of cold subcycle .12
6.4.3 Description of 24 h cycles with no exposure to cold .13
6.4.4 Description of final cycle.13
6.5 Final measurements .13
6.5.1 At high humidity.13
6.5.2 Immediately upon removal from the chamber.13
6.5.3 After final drying .13
7 Information to be given in the relevant specification .14
8 Information to be given in the test report .14

Figure 1 – Preconditioning .8
Figure 2 – Exposure to humidity followed by exposure to cold .10
Figure 3 – Exposure to humidity not followed by exposure to cold.11

60068-2-38 © IEC:2009 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ENVIRONMENTAL TESTING –
Part 2-38: Tests –
Test Z/AD: Composite temperature/humidity cyclic test

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
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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 60068-2-38 has been prepared by IEC technical committee 104:
Environmental conditions, classification and methods of test.
This second edition cancels and replaces the first edition, published in 1974, and constitutes
a technical revision.
The major changes with regard to the previous edition concern the updating of the figures,
changes to some of the wording and editorial corrections made for clarification.
The text of this standard is based on the following documents:
FDIS Report on voting
104/482/FDIS 104/487/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.

– 4 – 60068-2-38 © IEC:2009
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.
60068-2-38 © IEC:2009 – 5 –
ENVIRONMENTAL TESTING –
Part 2-38: Tests –
Test Z/AD: Composite temperature/humidity cyclic test

1 Scope
IEC 60068-2-38 provides a composite test procedure, primarily intended for component type
specimens, to determine, in an accelerated manner, the resistance of specimens to the
deteriorative effects of high temperature/humidity and cold conditions.
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 60068-1, Environmental testing – Part 1: General and guidance
IEC 60068-2-30, Environmental testing – Part 2-30: Tests – Test Db: Damp heat, cyclic (12 h
+ 12 h cycle)
IEC 60068-2-78, Environmental testing – Part 2-78: Tests – Test Cab: Damp heat, steady
state
IEC Guide 104, The preparation of safety publications and the use of basic safety publications
and group safety publications
3 General
...