IEC 60068-2-30:2005

Environmental testing - Part 2-30: Tests - Test Db: Damp heat, cyclic (12 h + 12 h cycle)

IEC 60068-2-30:2005 Determines the suitability of components, equipment or other articles for use, transportation and storage under conditions of high humidity - combined with cyclic temperature changes and, in general, producing condensation on the surface of the specimen. If the test is being used to verify the performance of a specimen whilst it is being transported or stored in packaging then the packaging will normally be fitted when the test conditions are being applied. For small, low mass specimens, it may be difficult to produce condensation on the surface of the specimen using this procedure; users should consider the use of an alternative procedure such as that given to IEC 60068-2-38. The main changes with respect to the previous edition are listed below:
- editorial changes,
- addition of normative references,
- addition of guidance for temperature tolerances,
- period for recovery has been extended.

Essais d'environnement - Partie 2-30: Essais - Essai Db: Essai cyclique de chaleur humide (cycle de 12 h + 12 h)

IEC 60068-2-30:2005 Détermine, par essai, l'aptitude des composants, des matériels ou de tous autres articles destinés à être utilisés, transportés ou stockés dans des conditions d'humidité relative élevée combinées avec des variations cycliques de température et, en général, avec formation de condensation à la surface des spécimens. Si l'essai est utilisé pour vérifier la performance d'un spécimen lors de son transport ou de son stockage dans son emballage, alors l'emballage sera bien ajusté lorsque les conditions d'essais sont appliquées. Pour les petits spécimens, de faible masse, il peut être difficile de produire de la condensation à la surface du spécimen soumis à ce mode opératoire; il est recommandé que les utilisateurs envisagent l'utilisation d'un mode opératoire alternatif tel qu'indiqué dans la CEI 60068-2-38. Les modifications principales par rapport à l'édition précédente sont les suivantes:
- modifications éditoriales,
- ajout de références normatives,
- ajout de lignes directrices pour les tolérances de température,
- prolongation de la période de reprise.

General Information

• Status: Published
• Publication Date: 09-Aug-2005
• 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: 10-Aug-2005
• Completion Date: 15-Dec-2005

Relations

• Revised: IEC 60068-2-30:2025 - Environmental testing - Part 2-30: Tests - Test Db: Damp heat, cyclic (12 h + 12 h cycle)
• Effective Date: 05-Sep-2023

Overview

IEC 60068-2-30:2005 - Test Db: Damp heat, cyclic (12 h + 12 h cycle) - is an IEC environmental test method that determines the suitability of components, equipment or other articles for use, transport and storage under high-humidity conditions combined with cyclic temperature changes that may produce surface condensation. The procedure defines a 24 h cycle (12 h high-temperature dwell + 12 h low-temperature dwell), chamber performance criteria, stabilization and recovery requirements, and optional severities (upper temperatures and number of cycles).

Key Topics and Requirements

• Test purpose: Verify resistance to damp heat with cyclic temperature changes and condensation on specimen surfaces.
• Stabilization: Specimens must be stabilized at 25 °C ± 3 K before cycles; relative humidity raised to ≥95% RH at 25 °C.
• 24 h cycle: Rise to the specified upper temperature within 3 h ± 30 min; maintain upper temperature for 12 h ± 30 min with 93% RH ± 3%; then lower temperature to 25 °C ± 3 K over 3–6 h and maintain RH conditions for the remainder of the cycle.
• Variants for temperature fall:
  • Variant 1: Requires controlled rate during the first 1.5 h of cooling and RH ≥95% (condensation likely).
  • Variant 2: Allows wider tolerances during temperature fall and RH ≥80% (for specimens less prone to condensation).
• Severities (examples given):
  • Upper temperature 40 °C - cycles: 2, 6, 12, 21, 56
  • Upper temperature 55 °C - cycles: 1, 2, 6
• Chamber performance: Temperature variation in the working space must be small - local differences should not exceed 1 K and short-term fluctuations may need to be within ±0.5 K to maintain RH tolerances. Total temperature tolerances of ±2 K to ±3 K are specified. Chamber water must have resistivity ≥500 Ω·m; condensed water must be drained and not reused.
• Measurements: Initial, intermediate (if specified), recovery and final inspections/tests are required. Recovery period has been extended in this edition.

Applications and Users

• Practical applications: qualification testing for electronic components, assemblies, enclosures, and packaged goods exposed to humid climates or condensation during storage and transport.
• Typical users: environmental test laboratories, quality/qualification engineers, product reliability teams, suppliers in electronics, automotive, aerospace, telecommunications, and defense.
• Notes: Small, low-mass specimens that do not readily condense should consider alternative methods such as IEC 60068-2-38.

Related Standards

• IEC 60068-2-38 - Composite temperature/humidity cyclic test (alternative for low-mass specimens)
• IEC 60068-3-6 - Chamber performance confirmation for temperature/humidity tests
• IEC 60068-1 - General and guidance
• IEC 60068-5-2 - Terms and definitions for test methods

Keywords: IEC 60068-2-30, damp heat cyclic test, environmental testing, condensation, temperature cycle, humidity chamber, test Db, reliability testing.

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD 60068-2-30
Third edition
2005-08
Environmental testing –
Part 2-30:
Tests – Test Db:
Damp heat, cyclic (12 h + 12 h cycle)

This English-language version is derived from the original
bilingual publication by leaving out all French-language
pages. Missing page numbers correspond to the French-
language pages.
Reference number
Publication numbering
As from 1 January 1997 all IEC publications are issued with a designation in the

60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1.

Consolidated editions
The IEC is now publishing consolidated versions of its publications. For example,

edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the base publication, the

base publication incorporating amendment 1 and the base publication incorporating

amendments 1 and 2.
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INTERNATIONAL IEC
STANDARD 60068-2-30
Third edition
Environmental testing –
Part 2-30:
Tests – Test Db:
Damp heat, cyclic (12 h + 12 h cycle)

 IEC 2005 Copyright - all rights reserved
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 the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
PRICE CODE
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Commission Electrotechnique Internationale
International Electrotechnical Commission
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For price, see current catalogue

60068-2-30  IEC:2005 – 3 –
CONTENTS
FOREWORD.5

Scope.9
2 Normative references.9

3 General description.9

4 Testing chamber – Construction requirements.11

5 Severities .11

6 Initial measurements.13
7 Conditioning .13
8 Intermediate measurements.15
9 Recovery .15
10 Final measurements .17
11 Information to be given in the relevant specification.17
Annex A (informative) Selection of variant for the temperature-fall period – Guidance .27

Figure 1 – Test Db – Stabilizing period .19
Figure 2 – Test Db – Test cycle – Variants 1 and 2 .23
Figure 3 – Test Db – Recovery at controlled conditions.25

60068-2-30  IEC:2005 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

___________
ENVIRONMENTAL TESTING –
Part 2-30: Tests – Test Db :
Damp heat, cyclic (12 h + 12 h cycle)

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
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International Standard IEC 60068-2-30 has been prepared by IEC technical committee 104:
Environmental conditions, classification and methods of test.
This third edition cancels and replaces the second edition (1980) and its amendment 1 (1985),
and constitutes a technical revision.
The main changes with respect to the previous edition are listed below:
– editorial changes,
– addition of normative references,
– addition of guidance for temperature tolerances,
– period for recovery has been extended.

60068-2-30  IEC:2005 – 7 –
The text of this standard is based on the following documents:

FDIS Report on voting
104/369/FDIS 104/374/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.

This standard forms Part 2-30 of IEC 60068 which consists of the following major parts, under
the general title Environmental testing:
Part 1: General and guidance;
Part 2: Tests;
Part 3: Supporting documentation and guidance;
Part 4: Information for specification writers;
Part 5: Guide to drafting of test methods.
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.
60068-2-30  IEC:2005 – 9 –
ENVIRONMENTAL TESTING –
Part 2-30: Tests – Test Db:
Damp heat, cyclic (12 h + 12 h cycle)

1 Scope
This part of IEC 60068 determines the suitability of components, equipment or other articles for
use, transportation and storage under conditions of high humidity – combined with cyclic
temperature changes and, in general, producing condensation on the surface of the specimen.
If the test is being used to verify the performance of a specimen whilst it is being transported or
stored in packaging then the packaging will normally be fitted when the test conditions are
being applied.
For small, low mass specimens, it may be difficult to produce condensation on the surface of
the specimen using this procedure; users should consider the use of an alternative procedure
such as that given to IEC 60068-2-38.
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 60068-2-38, Environmental testing – Part 2-38: Tests – Test Z/AD: Composite
temperature/humidity cyclic test
IEC 60068-3-6, Environmental testing – Part 3-6: Supporting documentation and guidance –
Confirmation of the performance of temperature/humidity chambers
IEC 60068-1:1988, Environmental testing − Part 1: General and guidance
IEC 60068-5-2, Environmental testing − Part 5: Guide to drafting of test methods – Terms and
definitions
3 General description
This test comprises one or more temperature cycles in which the relative humidity is
maintained at a high level.
Two variants of the cycle are given which are identical except for the temperature fall period;
during this part of the cycle, variant 2 allows wider tolerances of relative humidity and the rate
of temperature fall.
The upper temperature of the cycle and the number of cycles (see Clause 5) determine the test
severity.
Test profiles illustrating the procedure are shown in Figures 1, 2a, 2b and 3.

60068-2-30  IEC:2005 – 11 –
The tolerances stated in this standard do not take measurement uncertainty into consideration.

4 Testing chamber – Construction requirements

4.1 The temperature can be varied cyclically between 25 °C ± 3 K and the appropriate upper

temperature specified with the tolerance and rate of change specified in 7.3 and Figures 2a or

2b, as applicable.
The total temperature tolerance of ±3 K is intended to take account of absolute errors in the

measurement, slow changes of temperature, and temperature variations of the working space.

However, in order to maintain the relative humidity within the required tolerances, it is
necessary to keep the temperature difference between any two points in the working space at
any moment within narrower limits. The required humidity conditions will not be achieved if
such temperature differences exceed 1 K. It may also be necessary to keep short-term
fluctuations within ±0,5 K to maintain the required humidity.
4.2 The relative humidity in the working space can be maintained within the limits given in 7.3
and in Figures 2a or 2b, as applicable.
4.3 Care shall be taken to ensure that the conditions prevailing at any point in the working
space are uniform and are as similar as possible to those prevailing in the immediate vicinity of
suitably located temperature and humidity sensing devices. The chamber shall meet the
performance criteria as detailed in IEC 60068-3-6.
4.4 The specimens under test shall not be subjected to radiant heat from the chamber
conditioning processes.
4.5 Water used for the maintenance of chamber humidity shall have a resistivity of not less
than 500 Ωm.
Condensed water shall be continuously drained from the chamber and not used again until it
has been re-purified.
Precautions shall be taken to ensure that no condensed water is allowed to fall on the
specimens.
4.6 The dimensions, properties and/or electrical loading of the specimens under test shall not
appreciably influence conditions within the chamber.

5 Severities
5.1 The combination of the upper temperature and the number of cycles define the severity of
the test.
5.2 The severity shall be chosen from the following:
a) upper temperature: 40 °C,
number of cycles: 2, 6, 12, 21, 56;
b) upper temperature: 55 °C,
...

NORME CEI
INTERNATIONALE 60068-2-30
Troisième édition
2005-08
Essais d’environnement –
Partie 2-30:
Essais – Essai Db:
Essai cyclique de chaleur humide
(cycle de 12 h + 12 h)
Cette version française découle de la publication d’origine
bilingue dont les pages anglaises ont été supprimées.
Les numéros de page manquants sont ceux des pages
supprimées.
Numéro de référence
CEI 60068-2-30:2005(F)
Numérotation des publications
Depuis le 1er janvier 1997, les publications de la CEI sont numérotées à partir de

60000. Ainsi, la CEI 34-1 devient la CEI 60034-1.

Editions consolidées
Les versions consolidées de certaines publications de la CEI incorporant les

amendements sont disponibles. Par exemple, les numéros d’édition 1.0, 1.1 et 1.2

indiquent respectivement la publication de base, la publication de base incorporant

l’amendement 1, et la publication de base incorporant les amendements 1 et 2

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NORME CEI
INTERNATIONALE 60068-2-30
Troisième édition
2005-08
Essais d’environnement –
Partie 2-30:
Essais – Essai Db:
Essai cyclique de chaleur humide
(cycle de 12 h + 12 h)
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International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
CODE PRIX
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Commission Electrotechnique Internationale
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
Pour prix, voir catalogue en vigueur

– 2 – 60068-2-30  CEI:2005
SOMMAIRE
AVANT-PROPOS.4

1 Domaine d’application .8

2 Références normatives.8

3 Description générale .8

4 Chambre d’essai − Conditions de construction .10

5 Sévérités .10

6 Mesures initiales .12
7 Conditionnement .12
8 Mesures intermédiaires .14
9 Reprise .14
10 Mesures finales .16
11 Renseignements à fournir dans la spécification particulière.16

Annexe A (informative) Sélection de la variante pour la période de diminution de la
température – Lignes directrices .26

Figure 1 – Essai Db – Période de stabilisation .18
Figure 2 – Essai Db – Cycle d’essai – Variantes1 et 2 .22
Figure 3 – Essai Db – Reprise sous conditions contrôlées .24

– 4 – 60068-2-30  CEI:2005
COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE

____________
ESSAIS D’ENVIRONNEMENT –
Partie 2-30: Essais – Essai Db:

Essai cyclique de chaleur humide (cycle de 12 h + 12 h)

AVANT-PROPOS
1) La Commission Electrotechnique Internationale (CEI) est une organisation mondiale de normalisation
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La Norme internationale CEI 60068-2-30 a été établie par le comité d'études 104 de la CEI:
Conditions, classification et essais d’environnement.
Cette troisième édition annule et remplace la deuxième édition (1980) et son amendement 1
(1985), dont elle constitue une révision technique.
Les modifications principales par rapport à l’édition précédente sont les suivantes:
– modifications éditoriales,
– ajout de références normatives,
– ajout de lignes directrices pour les tolérances de température,
– prolongation de la période de reprise.

– 6 – 60068-2-30  CEI:2005
Le texte de cette norme est issu des documents suivants:

FDIS Rapport de vote
104/369/FDIS 104/374/RVD
Le rapport de vote indiqué dans le tableau ci-dessus donne toute information sur le vote ayant

abouti à l'approbation de cette norme.

Cette publication a été rédigée selon les Directives ISO/CEI, Partie 2.

Cette norme constitue la Partie 2-30 de la CEI 60068 qui comporte les parties principales
suivantes, présentées sous le titre général Essais d’environnement:
Partie 1: Généralités et guide;
Partie 2: Essais;
Partie 3: Documentation d'accompagnement et guide;
Partie 4: Renseignements destinés aux rédacteurs de spécification;
Partie 5: Guide pour la rédaction des méthodes d'essais.
Le comité a décidé que le contenu de cette publication ne sera pas modifié avant la date de
maintenance indiquée sur le site web de la CEI sous "http://webstore.iec.ch" dans les

données relatives à la publication recherchée. A cette date, la publication sera
• reconduite,
• supprimée,
• remplacée par une édition révisée, ou
• amendée.
– 8 – 60068-2-30  CEI:2005
ESSAIS D’ENVIRONNEMENT –
Partie 2-30: Essais – Essai Db:

Essai cyclique de chaleur humide (cycle de 12 h + 12 h)

1 Domaine d’application
La présente partie de la CEI 60068 détermine, par essai, l’aptitude des composants, des
matériels ou de tous autres articles destinés à être utilisés, transportés ou stockés dans des
conditions d’humidité relative élevée combinées avec des variations cycliques de température
et, en général, avec formation de condensation à la surface des spécimens. Si l’essai est
utilisé pour vérifier la performance d’un spécimen lors de son transport ou de son stockage
dans son emballage, alors l’emballage sera bien ajusté lorsque les conditions d’essais sont
appliquées.
Pour les petits spécimens, de faible masse, il peut être difficile de produire de la conden-
sation à la surface du spécimen soumis à ce mode opératoire ; il est recommandé que les
utilisateurs envisagent l’utilisation d’un mode opératoire alternatif tel qu’indiqué dans la
CEI 60068-2-38.
2 Références normatives
Les documents de référence suivants sont indispensables pour l'application du présent
document. Pour les références datées, seule l'édition citée s'applique. Pour les références
non datées, la dernière édition du document de référence s'applique (y compris les éventuels
amendements).
CEI 60068-2-38, Essais d'environnement – Partie 2-38: Essais – Essai Z/AD : Essai cyclique
composite de température et d’humidité
CEI 60068-3-6, Essais d'environnement – Partie 3-6: Documentation d'accompagnement et
guide – Confirmation des performances des chambres d'essai en température et humidité
CEI 60068-1:1988, Essais d'environnement − Première partie: Généralités et guide
CEI 60068-5-2, Essais d'environnement − Partie 5: Guide pour la rédaction des méthodes
d'essais – Termes et définitions

3 Description générale
Cet essai comporte un ou plusieurs cycles de température avec une humidité relative
maintenue à un niveau élevé.
Deux variantes du cycle sont données; elles sont identiques à l’exception de la période de
diminution de la température; pendant cette partie du cycle, la variante 2 admet des
tolérances plus grandes sur l’humidité relative et la vitesse de diminution de la température.
La sévérité de l’essai est déterminée par la température la plus élevée du cycle et par le
nombre de cycles (voir Article 5).
Les Figures 1, 2a, 2b et 3 illustrent le mode opératoire.

– 10 – 60068-2-30  CEI:2005
Les tolérances prescrites dans la présente norme ne prennent pas en considération les
incertitudes de mesures.
4 Chambre d’essai − Conditions de construction

4.1 La température peut varier cycliquement entre 25 °C ± 3 K et la température la plus

haute spécifiée, avec les tolérances et la vitesse de variation spécifiées en 7.3 et dans les

Figures 2a ou 2b, selon le cas.

La tolérance de température totale de ±3 K est destinée à prendre en compte les erreurs

absolues des mesures, des changements lents de température, et des variations de
températures de l’espace de travail. Cependant, afin de maintenir l’humidité relative au sein
des tolérances exigées, il est nécessaire de conserver la différence de température entre
deux points de l’espace de travail, à n’importe quel moment, au sein des plus étroites limites
possibles. Les conditions d’humidité exigées ne seront pas obtenues si de telles différences
de température excèdent 1 K. Il peut être aussi nécessaire de conserver des fluctuations de
faible durée au sein de ±0,5 K pour maintenir l’humidité exigée.
4.2 L’humidité relative dans l’espace de travail peut être maintenue dans les limites données
en 7.3 et dans les Figures 2a ou 2b, selon le cas.
4.3 Des précautions doivent être prises pour que les conditions qui règnent en tout point de
l’espace de travail soient homogènes et aussi voisines que possible de celles existant au
voisinage immédiat des dispositifs de mesure de température et d’humidité relative, disposés
de façon convenable. La chambre doit remplir les critères de performance détaillés dans la
CEI 60068-3-6.
4.4 Les spécimens en essai ne doivent pas être soumis à la chaleur rayonnée par les parois
de la chambre d’essai.
4.5 L’eau utilisée pour maintenir l’humidité de la chambre doit avoir une résistivité d’au
moins 500 Ωm.
L’eau de condensation doit être drainée, de façon continue, hors de la chambre et ne doit pas
être réutilisée avant d’être re-purifiée.
Des précautions doivent être prises pour que l’eau de condensation ne puisse pas tomber sur
les spécimens.
4.6 Les dimensions, les caractéristiques et/ou la dissipation des spécimens en essai ne

doivent pas influencer de façon appréciable les conditions régnant à l’intérieur de la chambre.
5 Sévérités
5.1 La sévérité de l’essai est définie par la combinaison de la température la plus haute et
du nombre d
...

IEC 60068-2-30
Edition 3.0 2005-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
Environmental testing –
Part 2-30: Tests – Test Db: Damp heat, cyclic (12 + 12 h cycle)

Essais d'environnement –
Partie 2-30: Essais – Essai Db: Essai cyclique de chaleur humide
(cycle de 12 h + 12 h)
Copyright © 1993 IEC, Geneva, Switzerland

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IEC 60068-2-30
Edition 3.0 2005-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
Environmental testing –
Part 2-30: Tests – Test Db: Damp heat, cyclic (12 + 12 h cycle)

Essais d'environnement –
Partie 2-30: Essais – Essai Db: Essai cyclique de chaleur humide
(cycle de 12 h + 12 h)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
N
CODE PRIX
ICS 19.040 ISBN 2-8318-8144-7
60068-2-30  IEC:2005 – 3 – – 2 – 60068-2-30 © IEC:2005
CONTENTS
FOREWORD.3

Scope.5
2 Normative references.5
3 General description.5
4 Testing chamber – Construction requirements.6
5 Severities .6
6 Initial measurements.7
7 Conditioning .7
8 Intermediate measurements.8
9 Recovery .8
10 Final measurements .9
11 Information to be given in the relevant specification.9
Annex A (informative) Selection of variant for the temperature-fall period – Guidance .14

Figure 1 – Test Db – Stabilizing period .10
Figure 2 – Test Db – Test cycle – Variants 1 and 2 .12
Figure 3 – Test Db – Recovery at controlled conditions.13

60068-2-30 © IEC:200560068-2-30  IEC:2005 – 5 – – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
ENVIRONMENTAL TESTING –
Part 2-30: Tests – Test Db :
Damp heat, cyclic (12 h + 12 h cycle)

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 60068-2-30 has been prepared by IEC technical committee 104:
Environmental conditions, classification and methods of test.
This third edition cancels and replaces the second edition (1980) and its amendment 1 (1985),
and constitutes a technical revision.
The main changes with respect to the previous edition are listed below:
– editorial changes,
– addition of normative references,
– addition of guidance for temperature tolerances,
– period for recovery has been extended.

– 4 – 60068-2-30 © IEC:2005
The text of this standard is based on the following documents:
FDIS Report on voting
104/369/FDIS 104/374/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.
This standard forms Part 2-30 of IEC 60068 which consists of the following major parts, under
the general title Environmental testing:
Part 1: General and guidance;
Part 2: Tests;
Part 3: Supporting documentation and guidance;
Part 4: Information for specification writers;
Part 5: Guide to drafting of test methods.
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.
60068-2-30 © IEC:200560068-2-30  IEC:2005 – 9 – – 5 –
ENVIRONMENTAL TESTING –
Part 2-30: Tests – Test Db:
Damp heat, cyclic (12 h + 12 h cycle)

1 Scope
This part of IEC 60068 determines the suitability of components, equipment or other articles for
use, transportation and storage under conditions of high humidity – combined with cyclic
temperature changes and, in general, producing condensation on the surface of the specimen.
If the test is being used to verify the performance of a specimen whilst it is being transported or
stored in packaging then the packaging will normally be fitted when the test conditions are
being applied.
For small, low mass specimens, it may be difficult to produce condensation on the surface of
the specimen using this procedure; users should consider the use of an alternative procedure
such as that given to IEC 60068-2-38.
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 60068-2-38, Environmental testing – Part 2-38: Tests – Test Z/AD: Composite
temperature/humidity cyclic test
IEC 60068-3-6, Environmental testing – Part 3-6: Supporting documentation and guidance –
Confirmation of the performance of temperature/humidity chambers
IEC 60068-1:1988, Environmental testing − Part 1: General and guidance
IEC 60068-5-2, Environmental testing − Part 5: Guide to drafting of test methods – Terms and
definitions
3 General description
This test comprises one or more temperature cycles in which the relative humidity is
maintained at a high level.
Two variants of the cycle are given which are identical except for the temperature fall period;
during this part of the cycle, variant 2 allows wider tolerances of relative humidity and the rate
of temperature fall.
The upper temperature of the cycle and the number of cycles (see Clause 5) determine the test
severity.
Test profiles illustrating the procedure are shown in Figures 1, 2a, 2b and 3.

60068-2-30  IEC:2005 – 11 – – 6 – 60068-2-30 © IEC:2005
The tolerances stated in this standard do not take measurement uncertainty into consideration.
4 Testing chamber – Construction requirements
4.1 The temperature can be varied cyclically between 25 °C ± 3 K and the appropriate upper
temperature specified with the tolerance and rate of change specified in 7.3 and Figures 2a or
2b, as applicable.
The total temperature tolerance of ±3 K is intended to take account of absolute errors in the
measurement, slow changes of temperature, and temperature variations of the working space.
However, in order to maintain the relative humidity within the required tolerances, it is
necessary to keep the temperature difference between any two points in the working space at
any moment within narrower limits. The required humidity conditions will not be achieved if
such temperature differences exceed 1 K. It may also be necessary to keep short-term
fluctuations within ±0,5 K to maintain the required humidity.
4.2 The relative humidity in the working space can be maintained within the limits given in 7.3
and in Figures 2a or 2b, as applicable.
4.3 Care shall be taken to ensure that the conditions prevailing at any point in the working
space are uniform and are as similar as possible to those prevailing in the immediate vicinity of
suitably located temperature and humidity sensing devices. The chamber shall meet the
performance criteria as detailed in IEC 60068-3-6.
4.4 The specimens under test shall not be subjected to radiant heat from the chamber
conditioning processes.
4.5 Water used for the maintenance of chamber humidity shall have a resistivity of not less
than 500 Ωm.
Condensed water shall be continuously drained from the chamber and not used again until it
has been re-purified.
Precautions shall be taken to ensure that no condensed water is allowed to fall on the
specimens.
4.6 The dimensions, properties and/or electrical loading of the specimens under test shall not
appreciably influence conditions within the chamber.
5 Severities
5.1 The combination of the upper temperature and the number of cycles define the severity of
the test.
5.2 The severity shall be chosen from the following:
a) upper temperature: 40 °C,
number of cycles: 2, 6, 12, 21, 56;
b) upper temperature: 55 °C,
number of cycles: 1, 2, 6.
60068-2-30 © IEC:200560068-2-30  IEC:2005 – 13 – – 7 –
6 Initial measurements
The specimens shall be visually inspected, and functionally tested, as required by the relevant
specification.
7 Conditioning
The specimens shall be introduced into the chamber either in the unpacked, switched-off,
ready-for-use state, or as otherwise specified in the relevant specification.
Where no specific mounting is prescribed, the thermal conduction of the mounting shall be low,
so that for all practical purposes the specimen is thermally isolated.
7.1 Temperature tolerances
The total temperature tolerance of ±2 K and ±3 K given in this standard is intended to take
account of absolute errors in the measurement, slow changes of temperature, and temperature
variations of the working space. However, in order to maintain the relative humidity within the
required tolerances, it is necessary to keep the temperature difference between any two points
in the working space at any moment within narrower limits. The required humidity conditions
will not be achieved if such temperature differences exceed 1 K. It may also be necessary to
keep short-term fluctuations within ±0,5 K to maintain the required humidity.
7.2 Stabilizing period
The temperature of the specimens shall be stabilized at 25 °C ± 3 K (the definition of
temperature stability is given in IEC 60068-1 and IEC 60068-5-2). This shall be achieved by
either
a) placing the specimens in a separate chamber before introducing it into the test chamber,
or,
b) adjusting the temperature of the test chamber to 25 °C ± 3 K after the introduction of the
specimens and maintaining them at this level until the specimens attain temperature
stability.
During the stabilization of temperature by either method, the relative humidity shall be within
the limits prescribed for standard atmospheric conditions for testing.
Following stabilization, with the specimens in the test chamber, the relative humidity shall be
increased to not less than 95 % RH at an ambient temperature of 25 °C ± 3 K.
7.3 Description of the 24 h cycle
7.3.1 The temperature of the chamber shall be raised to the appropriate upper temperature
prescribed by the relevant specification. The upper temperature shall be achieved in a period of
3 h ± 30 min and at a rate within the limits defined by the shaded areas in Figures 2a and 2b.
During this period, the relative humidity shall not be less than 95 % RH. During the last 15 min
it shall not be less than 90 % RH.

60068-2-30  IEC:2005 – 15 – – 8 – 60068-2-30 © IEC:2005
Condensation may occur on the specimen during this temperature-rise period.
NOTE The condensation condition implies that the surface temperature of the specimen is below the dew point of
the air in the chamber.
7.3.2 The temperature shall then be maintained within the prescribed limits for the upper
temperature (±2 K) until 12 h ± 30 min from the start of the cycle.
During this period, the relative humidity shall be 93 % RH ± 3 %RH. During the first and last
15 min it shall be between 90 % RH and 100 % RH.
7.3.3 The temperature shall then be lowered in accordance with one of the two variants given
below.
Variant 1 (see Figure 2a)
The temperature shall be lowered to 25 °C ± 3 K within 3 h to 6 h. The rate of fall for the first
one and one half hours shall be such that, if maintained as indicated in Figure 2a, it would
result in a temperature of 25 °C ±3 K being attained in 3 h ± 15 min. The relative humidity shall
be not less than 95 % RH. During the first 15 min it shall be not less than 90 % RH.
NOTE 1 See Annex A for descriptions of the type of specimen suitable for Variant 1.
Variant 2 (see Figure 2b)
The temperature shall be lowered to 25 °C ± 3 K within 3 h to 6 h, but without the additional
requirement for the first hour and one half as in variant 1. The relative humidity shall be not
less than 80 % RH.
NOTE 2 See Annex A for descriptions of the type of specimen suitable for Variant 2.
7.3.4 The temperature shall then be maintained at 25 °C ± 3 K with a relative humidity of not
less than 95 % RH until the 24 h cycle is completed.
8 Intermediate measurements
The relevant specification may require functional tests during the conditioning programme.
NOTE Measurements preceded by a recovery, which would require removal of the specimens from the chamber,
are not permissible during the conditioning. If it is desired to make intermediate measurements, the relevant
specification should define the measurements and the period(s) during the conditioning after which they will be
carried out.
9 Recovery
The relevant specification shall prescribe whether recovery shall be made at standard
atmospheric conditions for testing (see 5.3 of IEC 60068-1), or at controlled recovery
conditions (see 5.4.1 of IEC 60068-1).
If controlled recovery conditions are required (see Figure 3), the specimen may be transferred
to another chamber for this recovery period or may remain in the damp heat chamber.
In the former case, the change over time shall be as short as possible and not more than
10 min.
60068-2-30 © IEC:200560068-2-30  IEC:2005 – 17 – – 9 –
In the latter case, the relative humidity shall be reduced to 75 % RH ± 2 % RH in not more than
1 h. The temperature shall then be adjusted to laboratory temperature within ±1 K in not more
than one further hour. For large specimens, the relevant specification may allow longer change
over times.
The recovery time of 1 h to 2 h is counted from the moment when the prescribed recovery
conditions have been obtained.
Specimens having a large thermal time constant may be submitted to recovery for a period
sufficient to attain temperature stability (see Clause 4 of 60068-1).
The relevant specification shall state whether any special precautions shall be taken regarding
the removal of surface moisture.
10 Final measurements
The specimens shall be visually inspected, and functionally tested as required by the relevant
specification.
The measurements shall be commenced immediately after the recovery period and the
parameters most sensitive to changes of relative humidity shall be measured first. Unless
otherwise specified, the measurement of these parameters shall be completed within 30 min.
11 Information to be given in the relevant specification
When this test is included in the relevant specification, the following details shall be given as
far as they are applicable.
Clause or subclause
a) Severity: temperature and number of cycles.5.2
b) Initial measurements .6
c) State of the specimen during conditioning .7
d) Details of mounting or supports.7
e) Variant 1 or variant 2 . 7.3.3
f) Intermediate measurements.8
g) Recovery conditions.9
h) Special precautions to be taken regarding removal of surface moisture .9
i) Visual inspection and/or functional tests to be made at the end of the test,
the parameters to be measured first, and the maximum period allowed
for the measurement of these parameters (final measurements) .10

60068-2-30  IEC:2005 – 19 – – 10 – 60068-2-30 © IEC:2005

Stabilizing period
Start of first cycle
75 %
40 45 %
Time required to reach 95 % to 100 %
relative humidity (not exceeding 1 h)
Time
Start of first cycle
28 °C
22 °C
15 Time required for test specimen
to reach temperature stability
IEC  1232/05
Figure 1 – Test Db – Stabilizing period

Ambient temperature  °C
Relative humidity  %
60068-2-30 © IEC:200560068-2-30  IEC:2005 – 21 – – 11 –

Start of temperature fall
End of temperature rise
96 %
95 %
95 %
90 %
30 min 15 min 15 min
Time
Upper temperature +2 K
+40
or
+55
Upper temperature –2 K
+28 °C
+25
1 h +22 °C
1 h 30
30 min
30 min
3 h 3 h
12 h ± 30 min 6 h
24 h
IEC  1233/05
Figure 2a – Test Db – Test cycle – Variant 1

Ambient temperature  °C
Relative humidity  %
60068-2-30  IEC:2005 – 23 – – 12 – 60068-2-30 © IEC:2005

End of temperature rise
Start of temperature fall
96 %
95 %
95 %
90 %
80 %
15 min 15 min
15 min
Time
Upper temperature +2 K
+40
or
+55
Upper temperature –2 K
+28 °C
+25
1 h +22 °C
30 min 30 min
3 h 3 h
12 h ± 30 min 6 h
24 h
IEC  1234/05
Figure 2b – Test Db – Test cycle – Variant 2
Figure 2 – Test Db – Test cycle – Variants 1 and 2

Ambient temperature  °C
Relative humidity  %
60068-2-30 © IEC:200560068-2-30  IEC:2005 – 25 – – 13 –

100 %
End of recovery
95 %
77 %
80 75 %
73 %
≤1 h
40 45 %
Time
End of last cycle
Laboratory temperature
(15 °C to 35 °C)
+28 °C
+25
+22 °C
≤1 h
...