IEC 60068-2-38:2021

Environmental testing - Part 2-38: Tests - Test Z/AD: Composite temperature/humidity cyclic test

IEC 60068-2-38:2021 is available as IEC 60068-2-38:2021 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 60068-2-38:2021 specifies 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. This test standard does not apply to specimens that are energized during the complete test. Specimens can be energized during the constant phases of the tests. Measurements on energized specimens are typically carried out during constant phases of the test unless specified otherwise. This third edition cancels and replaces the second edition, published in 2009. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- the figures have been updated;
- changes to the wording has been made for clarification purposes.

Essais d'environnement - Partie 2-38: Essais - Essai Z/AD: Essai cyclique composite de température et d'humidité

IEC 60068-2-38:2021 est disponible sous forme de IEC 60068-2-38:2021 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.
L'IEC 60068-2-38:2021 spécifie une procédure d'essai composite, essentiellement destinée aux spécimens de type composant, dans le but de déterminer d'une manière accélérée la résistance des spécimens aux effets destructifs dus à des séjours dans des conditions de température/d'humidité élevées, alternées avec des conditions de froid. La présente norme d'essai ne s'applique pas aux spécimens qui sont mis sous tension durant toute la durée de l'essai. Les spécimens peuvent être mis sous tension durant les phases constantes des essais. Les mesures réalisées sur des spécimens sous tension ont généralement lieu durant les phases constantes de l'essai, sauf spécification contraire. Cette troisième édition annule et remplace la deuxième édition parue en 2009. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente
- les figures ont été mises à jour;
- la formulation a été modifiée à des fins de clarification.

General Information

• Status: Published
• Publication Date: 24-Mar-2021
• 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: 16-Apr-2021
• Completion Date: 25-Mar-2021

Relations

• Revises: IEC 60068-2-38:2009 - Environmental testing - Part 2-38: Tests - Test Z/AD: Composite temperature/humidity cyclic test
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60068-2-38 ®
Edition 3.0 2021-03
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Environmental testing –
Part 2-38: Tests – Test Z/AD: Composite temperature/humidity cyclic test
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
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About the IEC
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IEC 60068-2-38 ®
Edition 3.0 2021-03
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Environmental testing –
Part 2-38: Tests – Test Z/AD: Composite temperature/humidity cyclic test
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 19.040 ISBN 978-2-8322-9633-2

– 2 – IEC 60068-2-38:2021 RLV © IEC 2021
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 General . 7
4.1 Description of the test . 7
4.2 Application of the test . 7
5 Description of test chamber . 8
5.1 General . 8
5.2 Chamber for exposure to moisture . 8
5.3 Chamber for exposure to cold . 9
6 Severities . 9
7 Testing procedure . 9
7.1 Preconditioning . 9
7.2 Initial measurements . 10
7.3 Conditioning . 10
7.4 Test cycle . 13
7.4.1 Description of temperature/humidity subcycle . 13
7.4.2 Description of cold subcycle . 14
7.4.3 Description of 24 h cycles with no exposure to cold . 15
7.4.4 Description of final cycle . 15
7.4.5 Intermediate measurements. 15
7.5 Final measurements . 17
7.5.1 Introductory remarks . 17
7.5.2 At high humidity . 18
7.5.3 Immediately upon removal from the chamber . 18
7.5.4 After final drying . 18
8 Information to be given in the relevant specification . 18
9 Information to be given in the test report. 19
Annex A (informative) Supporting documentation for test sequence . 21
A.1 General . 21
A.2 Preconditioning . 21
A.3 Exposure to humidity followed by exposure to cold . 22
A.4 Exposure to humidity not followed by exposure to cold. 23
Bibliography . 24
Figure 1 – Preconditioning . 10
Figure 2 – Exposure to humidity followed by exposure to cold. 12
Figure 3 – Exposure to humidity not followed by exposure to cold . 13
Figure 4 – Test times for intermediate operation of specimen – Exposure to humidity
followed by exposure to cold . 16
Figure 5 – Test times for intermediate operation of specimen – Exposure to humidity
not followed by exposure to cold . 17

Table A.1 – Relative humidity tolerances . 21
Table A.2 – Temperature tolerances . 21
Table A.3 – Tolerances of relative humidity and temperature during exposure to
humidity followed by exposure to cold . 22
Table A.4 – Tolerances of relative humidity and temperature during exposure to

humidity not followed by exposure to cold . 23

– 4 – IEC 60068-2-38:2021 RLV © IEC 2021
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 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.
This redline version of the official IEC Standard allows the user to identify the changes made to
the previous edition IEC 60068-2-38:2009. A vertical bar appears in the margin wherever a change
has been made. Additions are in green text, deletions are in strikethrough red text.

IEC 60068-2-38 has been prepared by IEC technical committee 104: Environmental conditions,
classification and methods of test. It is an International Standard.
This third edition cancels and replaces the second 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) the figures have been updated;
b) changes to the wording has been made for clarification purposes.
The text of this International Standard is based on the following documents:
Draft Report on voting
104/891/FDIS 104/896/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
A list of all parts in the IEC 60068 series, published under the general title Environmental testing,
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.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates that it
contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.

– 6 – IEC 60068-2-38:2021 RLV © IEC 2021
ENVIRONMENTAL TESTING –
Part 2-38: Tests –
Test Z/AD: Composite temperature/humidity cyclic test

1 Scope
This part of IEC 60068
...

IEC 60068-2-38 ®
Edition 3.0 2021-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
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
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
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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 online collection - oc.iec.ch
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committee, …). It also gives information on projects, replaced have access to up to date content tailored to your needs.
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containing more than 22 000 terminological entries in English
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IEC 60068-2-38 ®
Edition 3.0 2021-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
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
INTERNATIONALE
ICS 19.040 ISBN 978-2-8322-9586-1

– 2 – IEC 60068-2-38:2021 © IEC 2021
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 General . 6
4.1 Description of the test . 6
4.2 Application of the test . 7
5 Description of test chamber . 8
5.1 General . 8
5.2 Chamber for exposure to moisture . 8
5.3 Chamber for exposure to cold . 8
6 Severities . 9
7 Testing procedure . 9
7.1 Preconditioning . 9
7.2 Initial measurements . 10
7.3 Conditioning . 10
7.4 Test cycle . 13
7.4.1 Description of temperature/humidity subcycle . 13
7.4.2 Description of cold subcycle . 14
7.4.3 Description of 24 h cycles with no exposure to cold . 15
7.4.4 Description of final cycle . 15
7.4.5 Intermediate measurements. 15
7.5 Final measurements . 17
7.5.1 Introductory remarks . 17
7.5.2 At high humidity . 18
7.5.3 Immediately upon removal from the chamber . 18
7.5.4 After final drying . 18
8 Information to be given in the relevant specification . 18
9 Information to be given in the test report. 19
Annex A (informative) Supporting documentation for test sequence . 20
A.1 General . 20
A.2 Preconditioning . 20
A.3 Exposure to humidity followed by exposure to cold . 21
A.4 Exposure to humidity not followed by exposure to cold. 22
Bibliography . 23

Figure 1 – Preconditioning . 10
Figure 2 – Exposure to humidity followed by exposure to cold. 12
Figure 3 – Exposure to humidity not followed by exposure to cold . 13
Figure 4 – Test times for intermediate operation of specimen – Exposure to humidity
followed by exposure to cold . 16
Figure 5 – Test times for intermediate operation of specimen – Exposure to humidity
not followed by exposure to cold . 17

Table A.1 – Relative humidity tolerances . 20
Table A.2 – Temperature tolerances . 20
Table A.3 – Tolerances of relative humidity and temperature during exposure to
humidity followed by exposure to cold . 21
Table A.4 – Tolerances of relative humidity and temperature during exposure to

humidity not followed by exposure to cold . 22

– 4 – IEC 60068-2-38:2021 © IEC 2021
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 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 o
...