EN IEC 60068-3-4:2023

SLOVENSKI STANDARD
01-maj-2024
Nadomešča:
SIST EN 60068-3-4:2002
Okoljsko preskušanje - 3-4. del: Podporna dokumentacija in navodila - Vlažni
toplotni preskusi (IEC 60068-3-4:2023)
Environmental testing - Part 3-4: Supporting documentation and guidance - Damp heat
tests (IEC 60068-3-4:2023)
Umweltprüfungen - Teil 3-4: Unterstützende Dokumentation und Leitfaden - Prüfungen
mit feuchter Wärme (IEC 60068-3-4:2023)
Essais d'environnement - Partie 3-4: Documentation d'accompagnement et
recommandations - Essais de chaleur humide (IEC 60068-3-4:2023)
Ta slovenski standard je istoveten z: EN IEC 60068-3-4:2023
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 IEC 60068-3-4

NORME EUROPÉENNE
EUROPÄISCHE NORM September 2023
ICS 19.040; 29.020 Supersedes EN 60068-3-4:2002
English Version
Environmental testing - Part 3-4: Supporting documentation and
guidance - Damp heat tests
(IEC 60068-3-4:2023)
Essais d'environnement - Partie 3-4: Documentation Umgebungseinflüsse - Teil 3-4: Unterstützende
d'accompagnement et recommandations - Essais de Dokumentation und Leitfaden - Prüfungen Feuchte Wärme
chaleur humide (IEC 60068-3-4:2023)
(IEC 60068-3-4:2023)
This European Standard was approved by CENELEC on 2023-08-03. 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 CEN-CENELEC
Management Centre 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 CEN-CENELEC Management Centre has the
same status as the official versions.
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,
Türkiye 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
© 2023 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60068-3-4:2023 E

European foreword
The text of document 104/985/FDIS, future edition 2 of IEC 60068-3-4, prepared by IEC/TC 104
"Environmental conditions, classification and methods of test" was submitted to the IEC-CENELEC
parallel vote and approved by CENELEC as EN IEC 60068-3-4:2023.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2024-05-03
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2026-08-03
document have to be withdrawn
This document supersedes EN 60068-3-4:2002 and all of its amendments and corrigenda (if any).
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.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 60068-3-4:2023 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 60068-1 NOTE Approved as EN 60068-1
IEC 60068-2-1 NOTE Approved as EN 60068-2-1
IEC 60068-2-10 NOTE Approved as EN 60068-2-10
IEC 60068-2-14 NOTE Approved as EN 60068-2-14
IEC 60068-2-17 NOTE Approved as EN 60068-2-17
IEC 60068-2-30 NOTE Approved as EN 60068-2-30
IEC 60068-2-38 NOTE Approved as EN IEC 60068-2-38
IEC 60068-2-39 NOTE Approved as EN 60068-2-39
IEC 60068-2-66 NOTE Approved as EN 60068-2-66
IEC 60068-2-67 NOTE Approved as EN 60068-2-67
IEC 60068-2-78 NOTE Approved as EN 60068-2-78
IEC 60721-2-1 NOTE Approved as EN 60721-2-1

IEC 60068-3-4 ®
Edition 2.0 2023-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Environmental testing –
Part 3-4: Supporting documentation and guidance – Damp heat tests

Essais d'environnement –
Partie 3-4: Documentation d'accompagnement et recommandations – Essais de

chaleur humide
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 19.040, 29.020 ISBN 978-2-8322-7135-3

– 2 – IEC 60068-3-4:2023 © IEC 2023
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Procedures for the production and control of humidity . 7
4.1 General . 7
4.2 Injection of water (spraying) . 7
4.3 Injection of water vapour (steam) . 7
4.4 Saturation type . 8
4.5 Surface evaporation . 8
4.6 Aqueous solutions. 8
4.7 Dehumidification . 8
4.8 Control of humidity . 8
5 Physical appearance of the effects of humidity . 8
5.1 General . 8
5.2 Condensation . 9
5.3 Adsorption . 9
5.4 Absorption . 9
5.5 Diffusion . 9
6 Acceleration of tests . 10
6.1 General . 10
6.2 Acceleration factor . 10
7 Comparison of steady-state and cyclic tests . 10
7.1 Test C: Damp heat, steady-state . 10
7.2 Test Db: Damp heat, cyclic test . 11
7.3 Sequences of tests and composite tests . 11
8 Influence of test environment on specimens . 11
8.1 Change of physical characteristics . 11
8.2 Change of electrical characteristics . 12
8.2.1 With surface moisture . 12
8.2.2 With penetrated moisture . 12
8.3 Corrosion . 12
Annex A (informative) Humidity effects diagram . 13
A.1 General . 13
A.2 Explanatory notes . 13
A.2.1 Water penetration . 13
A.2.2 Examples of effects . 14
Bibliography . 17

Figure A.1 – Physical processes involved in humidity testing . 15

IEC 60068-3-4:2023 © IEC 2023 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ENVIRONMENTAL TESTING –
Part 3-4: Supporting documentation and guidance – Damp heat tests

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
can 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 can be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC 60068-3-4 has been prepared by IEC technical committee 104: Environmental conditions,
classification and methods of test. It is an International Standard.
This second edition cancels and replaces the first edition published in 2001. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the requirements for distilled and deionized water have been revised;
b) recommendations for the cleaning procedure of test chambers have been included;
c) humidification systems (ultrasonic humidifiers and atomizers) have been added;
d) the description of water penetration mechanisms has been refined.

– 4 – IEC 60068-3-4:2023 © IEC 2023
The text of this International Standard is based on the following documents:
Draft Report on voting
104/985/FDIS 104/1001/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/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 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.
IEC 60068-3-4:2023 © IEC 2023 – 5 –
INTRODUCTION
Temperature and relative humidity (RH) of the air, in varying combinations, are climatic factors
which act upon a product during storage, transportation and operation.
Meteorological measurements made over many years have shown that a relative
humidity > 95 % combined with a temperature > 30 °C does not occur in free-air conditions over
long periods, except in regions with extreme climates. In dwelling rooms and workshops
temperatures of > 30 °C can occur but in most cases are combined with a lower relative humidity
than in the open air.
Special conditions exist in certain wet rooms, for example in the chemical industry, metallurgical
plants, mines, electroplating plants and laundries, where the temperature can reach 45 °C
combined with a relative humidity up to saturation over long periods.
Certain equipment placed under particular conditions can be subjected to a relative humidity of
more than 95 % at higher temperatures. This can happen when the equipment is placed in
enclosures, such as vehicles, tents or aircraft cockpits, since this can result in intense heating
through solar radiation while, because of inadequate ventilation, any humidity that can be
developed will be retained permanently within the interior.
In rooms having several heat sources, temperatures and relative humidity can vary in different
parts of the room.
To take these climatic factors over the lifetime of the product into account, environmental testing
includes the practice of accelerated testing (see Clause 6).
Atmospheric pollution can intensify the effects of a damp climate on products. Attention is drawn
to this fact because of its general importance, although pollutants are not contained in the
atmospheres used for damp heat testing. If the effects of pollutants, for example corrosion and
mould growth, are to be investigated, a suitable test from the IEC 60068-2 series should be
used.
– 6 – IEC 60068-3-4:2023 © IEC 2023
ENVIRONMENTAL TESTING –
Part 3-4: Supporting documentation and guidance – Damp heat tests

1 Scope
This part of IEC 60068 provides the necessary information and the basic principles of the effect
of humidity in the context of environmental testing to assist in preparing relevant specifications,
such as standards for components or equipment. Furthermore, information is provided on
operating climatic test chambers.
The object of this document is to present supporting documentation and guidance for a range
of damp heat tests which, when specified by the relevant specification, can be applied to
demonstrate the performance of equipment for which damp heat testing is required with the
main aim of achieving qualification. This information and basic principles are intended to help
selecting appropriate tests and test severities for specific products and, in some cases, specific
types of application.
The object of damp heat tests is to determine the ability of products to withstand the stresses
occurring in a high relative humidity environment, with or without condensation, and with special
regard to variations of electrical and mechanical characteristics. Damp heat tests can also be
utilized to check the resistance of a specimen to some forms of corrosion attack.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
NOTE A more detailed explanation of some phenomena is available in A.2.1.
3.1
condensation
precipitation of water vapour on a surface when the surface temperature is lower than the dew
point temperature of the ambient air whereby water is transformed from vapour to the liquid
state of aggregation
3.2
adsorption
adherence of water vapour molecules to a surface when the surface temperature is higher than
the dew point temperature
3.3
absorption
accumulation of water molecules within a material

IEC 60068-3-4:2023 © IEC 2023 – 7 –
3.4
diffusion
transportation of water molecules through a material, induced by a partial pressure difference
Note 1 to entry: Diffusion results in a balance of partial pressures, whilst flow (such as through leaks, when the
dimensions of such leaks are great enough to provide viscous or laminar flow) always finally results in the balance
of the total pressures.
3.5
breathing
exchange of air between a hollow space and its surroundings, induced by changes of
temperature or pressure
4 Procedures for the production and control of humidity
4.1 General
There are a great number of humidity test chambers available, equipped with different methods
of humidity generation and of humidity control.
The water resistivity should be between 2 000 Ωm to 500 Ωm corresponding to a conductivity
between 5 µS/cm to 20 µS/cm at +23 °C. Before the water is placed in the humidifier or storage
tank of the chamber, all internal parts of the chamber should be cleaned.
NOTE 1 A conductivity lower than 5 µS/cm can harm the humidifier system. A conductivity higher than 20 µS/cm
can cause limescale or other mineral deposits to form on parts of the humidifier system or specimen.
The chamber and its internal parts can be cleaned using diluted laboratory cleaning agent and
a soft brush and rinsed with distilled or deionized water. It is recommended that the chamber is
cleaned prior to each test. The test facility should be operated in a clean area.
NOTE 2 Chamber sensors can be affected by the cleaning procedure, as some sensors (e.g. capacitive humidity
sensors) can be damaged by some cleaning agents.
NOTE 3 D
...