kSIST FprEN IEC 60068-3-4:2023

SLOVENSKI STANDARD
oSIST prEN IEC 60068-3-4:2022
01-september-2022
Okoljsko preskušanje - 3-4. del: Podporna dokumentacija in navodilo - Vlažni
toplotni preskusi
Environmental testing - Part 3-4: Supporting documentation and guidance - Damp heat
tests
Umweltprüfungen - Teil 3-4: Unterstützende Dokumentation und Leitfaden - Prüfungen
mit feuchter Wärme
Essais d'environnement - Partie 3-4: Documentation d'accompagnement et
recommandations - Essais de chaleur humide
Ta slovenski standard je istoveten z: prEN IEC 60068-3-4:2022
ICS:
19.040 Preskušanje v zvezi z Environmental testing
okoljem
29.020 Elektrotehnika na splošno Electrical engineering in
general
oSIST prEN IEC 60068-3-4:2022 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN IEC 60068-3-4:2022

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oSIST prEN IEC 60068-3-4:2022
104/931/CDV

COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60068-3-4 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2022-06-24 2022-09-16
SUPERSEDES DOCUMENTS:
104/910/CD, 104/923A/CC

IEC TC 104 : ENVIRONMENTAL CONDITIONS, CLASSIFICATION AND METHODS OF TEST
SECRETARIAT: SECRETARY:
Sweden Mr Henrik Lagerström
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:


Other TC/SCs are requested to indicate their interest, if
any, in this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.

This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of
which they are aware and to provide supporting documentation.

TITLE:
Environmental testing - Part 3-4: Supporting documentation and guidance - Damp heat tests

PROPOSED STABILITY DATE: 2027

NOTE FROM TC/SC OFFICERS:


Copyright © 2022 International Electrotechnical Commission, IEC. All rights reserved. It is permitted to
download this electronic file, to make a copy and to print out the content for the sole purpose of preparing National
Committee positions. You may not copy or "mirror" the file or printed version of the document, or any part of it,
for any other purpose without permission in writing from IEC.

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1 CONTENTS
2
3 FOREWORD. 4
4 INTRODUCTION . 5
5 1 Scope . 5
6 2 Normative references . 5
7 3 Definitions . 5
8 4 Procedures for the production and control of humidity . 7
9 4.1 General . 7
10 4.2 Injection of water (spraying) . 7
11 4.3 Injection of water vapour (steam) . 7
12 4.4 Saturation type . 7
13 4.5 Surface evaporation. 8
14 4.6 Aqueous solutions . 8
15 4.7 Dehumidification . 8
16 4.8 Control of humidity . 8
17 5 Physical appearance of the effects of humidity . 8
18 5.1 Condensation . 8
19 5.2 Adsorption . 9
20 5.3 Absorption . 9
21 5.4 Diffusion . 9
22 6 Acceleration of tests . 9
23 6.1 General . 9
24 6.2 Acceleration factor . 10
25 7 Comparison of steady-state and cyclic tests . 10
26 7.1 Test C: Damp heat, steady-state . 10
27 7.2 Test Db: Damp heat, cyclic test . 10
28 7.3 Sequences of tests and composite tests . 10
29 8 Influence of test environment on specimens . 11
30 8.1 Change of physical characteristics . 11
31 8.2 Change of electrical characteristics . 11
32 8.2.1 With surface moisture . 11
33 8.2.2 With penetrated moisture . 11
34 8.3 Corrosion . 12
35 Annex A (informative) Humidity effects diagram . 13
36 A.1 General . 13
37 A.2 Explanatory notes . 13
38 A.2.1 Water penetration . 13
39 A.2.2 Examples of effects . 14
40 Bibliography . 18
41
42 Figure A.1– Physical processes involved in humidity testing . 15
43

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44 INTERNATIONAL ELECTROTECHNICAL COMMISSION
45 ____________
46
47 ENVIRONMENTAL TESTING –
48
49 Part 3-4: Supporting documentation and guidance –
50 Damp heat tests
51
52 FOREWORD
53 1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
54 all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
55 international co-operation on all questions concerning standardization in the electrical and electronic fields. To
56 this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
57 entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
58 participate in this preparatory work. International, governmental and non-governmental organizations liaising with
59 the IEC also participate in this preparation. The IEC collaborates closely with the International Organization for
60 Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
61 2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
62 international consensus of opinion on the relevant subjects since each technical committee has representation
63 from all interested National Committees.
64 3) The documents produced have the form of recommendations for international use and are published in the form
65 of standards, technical specifications, technical reports or guides and they are accepted by the National
66 Committees in that sense.
67 4) In order to promote international unification, IEC National Committees undertake to apply IEC International
68 Standards transparently to the maximum extent possible in their national and regional standards. Any divergence
69 between the IEC Standard and the corresponding national or regional standard shall be clearly indicated in the
70 latter.
71 5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
72 equipment declared to be in conformity with one of its standards.
73 6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
74 of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
75 International Standard IEC 60068-3-4 has been prepared by IEC Technical Committee 104:
76 Environmental conditions, classification and methods of test.
77 This second edition of IEC 60068-3-4 replaces the first edition of IEC 60068-3-4 published in
78 2001.
79 The text of this standard is based on the following documents:
FDIS Report on voting
104/208/FDIS 104/215/RVD
80
81 Full information on the voting for the approval of this standard can be found in the report on
82 voting indicated in the above table.
83 This publication has been drafted in accordance with the ISO/IEC Directives, Part 3.
84 Annex A is for information only.
85 The committee has decided that the contents of this publication will remain unchanged until
86 2026. At this date, the publication will be
87 • reconfirmed;
88 • withdrawn;
89 • replaced by a revised edition, or
90 • amended.
91

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92 INTRODUCTION
93 Temperature and relative humidity (RH) of the air, in varying combinations, are climatic factors
94 which act upon a product during storage, transportation and operation.
95 Meteorological measurements made over many years have shown that a relative humidity
96 >95 % combined with a temperature >30 °C does not occur in free air conditions over long
97 periods, except in regions with extreme climates. In dwelling rooms and workshops
98 temperatures of >30 °C may occur but in most cases are combined with a lower relative humidity
99 than in the open air.
100 Special conditions exist in certain wet rooms for example, in the chemical industry, metallurgical
101 plants, mines, electroplating plants and laundries, where the temperature can reach 45 °C
102 combined with a relative humidity up to saturation over long periods.
103 Certain equipment placed under particular conditions may be subjected to relative humidity of
104 more than 95 % at higher temperatures. This may happen when the equipment is placed in
105 enclosures, such as vehicles, tents or aircraft cockpits, since this can result in intense heating
106 through solar radiation while, because of inadequate ventilation, any humidity that may be
107 developed will be retained permanently within the interior.
108 In rooms having several heat sources, temperatures and relative humidity may vary in different
109 parts of the room.
110 To take these climatic factors over the lifetime of the product into account, environmental testing
111 includes the practice of accelerated testing (see 6).
112 Atmospheric pollution can intensify the effects of a damp climate on products. Attention is drawn
113 to this fact because of its general importance, although pollutants are not contained in the
114 atmospheres used for damp heat testing. If the effects of pollutants, for example corrosion and
115 mould growth, are to be investigated, a suitable test from the IEC 60068-2 series should be
116 used.
117

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118 ENVIRONMENTAL TESTING –
119
120 Part 3-4: Supporting documentation and guidance –
121 Damp heat tests
122
123
124
125 1 Scope
126 This part of IEC 60068 provides the necessary information to assist in preparing relevant
127 specifications, such as standards for components or equipment, in order to select appropriate
128 tests and test severities for specific products and, in some cases, specific types of application.
129 The object of damp heat tests is to determine the ability of products to withstand the stresses
130 occurring in a high relative humidity environment, with or without condensation, and with special
131 regard to variations of electrical and mechanical characteristics. Damp heat tests may also be
132 utilized to check the resistance of a specimen to some forms of corrosion attack.
133 2 Normative references
134 The following referenced documents are indispensable for the application of this document. For
135 dated references, only the edition cited applies. For undated references, the latest edition of
136 the referenced document (including any amendments) applies.
137 IEC 60068-1, Environmental testing – Part 1: General and guidance
138 IEC 60068-2-1, Environmental testing – Part 2: Tests. Tests A: Cold
139 IEC 60068-2-14, Environmental testing - Part 2-14: Tests - Test N: Change of temperature
140 IEC 60068-2-17, Environmental testing - Part 2-17: Tests - Test Q: Sealing
141 IEC 60068-2-30, Environmental testing - Part 2-30: Tests - Test Db: Damp heat, cyclic (12 h +
142 12 h cycle)
143 IEC 60068-2-38, Environmental testing - Part 2-38: Tests - Test Z/AD: Composite temperature/
144 humidity cyclic test
145 IEC 60068-2-39, Environmental testing - Part 2-39: Tests and Guidance: Combined temperature
146 or temperature and humidity with low air pressure tests
147 IEC 60068-2-66, Environmental testing - Part 2: Test methods - Test Cx: Damp heat, steady
148 state (unsaturated pressurized vapour)
149 IEC 60068-2-67, Environmental testing - Part 2-67: Tests - Test Cy: Damp heat, steady state,
150 accelerated test primarily intended for components
151 IEC 60068-2-78, Environmental testing - Part 2-78: Tests - Test Cab: Damp heat, steady state
152
153 3 Definitions
154 ISO and IEC maintain terminological databases for use in standardization at the following
155 addresses:

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156 - IEC Electropedia: available at http://www.electropedia.org/
157 - ISO online browsing platform: available at http://www.iso.org/obp
158 For the purpose of this part of IEC 60068, the following definitions apply.
159 NOTE A more detailed explanation of some phenomena is available in Annex A.2.1.
160
161 3.1
162 condensation
163 precipitation of water vapour on a surface when the surface temperature is lower than the
164 dewpoint temperature of the ambient air whereby water is transformed from vapour to the liquid
165 state of aggregation
166 3.2
167 adsorption
168 adherence of water vapour molecules to a surface when the surface temperature is higher than
169 the dewpoint temperature
170 3.3
171 absorption
172 accumulation of water molecules within a material
173 3.4
174 diffusion
175 transportation of water molecules through a material, induced by a partial pressure difference
176 Note 1 to entry: Diffusion results in a balance of partial pressures, whilst flow (such as through leaks, when the
177 dimensions of such leaks are great enough to provide viscous or laminar flow) always finally results in the balance
178 of the total pressures.
179 3.5
180 breathing
181 exchange of air between a hollow space and its surroundings, induced by changes of
182 temperature or pressure
183

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184 4 Procedures for the production and control of humidity
185 4.1 General
186 There are a great number of humidity test chambers available, equipped with different methods
187 of humidity generation and of humidity control.
188
189 The water resistivity shall be between 2 000 Ωm to 500 Ωm corresponding to a conductivity between 5
190 μS/cm to 20 μS/cm at +23 °C. Before the water is placed in the humidifier or storage tank of the chamber,
191 all internal parts of the chamber shall be cleaned.
192 NOTE A conductivity lower than 5 μS/cm might harm the humidifier system. A conductivity higher than 20 μS/cm
193 can cause limescale or other mineral deposits to form on parts of the humidifier system or specimen.
194 The chamber and its internal parts may be cleaned using diluted laboratory cleaning agent and
195 a soft brush and rinsed with distilled or deionized water. It is recommended that the chamber is
196 cleaned prior to each test.
197 During cleaning, it is recommended that gloves and a protective mask are used as a precaution
198 against the contamination of the test chamber and of the internal fixtures. The test facility should
199 be operated in a clean area.
200 Unless otherwise specified, the test specimen should be tested in the as-delivered condition
201 without any special treatment. Test items that are specially cleaned before the test may not
202 give an indication of effects which occur in service.
203 Sensors should not be modified during cleaning procedure and some sensors (e.g. capacitive
204 humidity sensors) might be damaged by some cleaning agents. Therefore, it must be ensured
205 that the used cleaning agent is compatible.
206 In the following subclauses, only the principal methods of generation of humidity are mentioned.
207 4.2 Injection of water (spraying)
208 Water is atomized to very fine particles or droplets.
209 The spray produced in this way moistens the air stream before it enters the working space, the
210 greater part of the droplets evaporating on the way. Small droplets of water may remain in the
211 airflow.
212 Direct water injection into the working space must be avoided, otherwise liquid water can
213 accumulate on the test specimen.
214 These simple systems provide rapid humidification and require little maintenance. Examples for
215 such humidification systems are ultrasonic humidifiers and atomization by means of a nozzle
216 (one- and two-substance nozzles).
217 4.3 Injection of water vapour (steam)
218 Evaporated water (steam) is blown into the working space of the chamber.
219 This system gives rapid humidification and is easier maintained (steam valve). However, the
220 resultant heat input may necessitate additional cooling with possible dehumidification effects.
221 4.4 Saturation type
222 Air is blown through a vessel containing water, thus becoming saturated with vapour.
223 At a fixed airflow, the humidity is controlled by changing the water temperature. If an increase
224 of humidification is produced by increasing the water temperature, this may cause a

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225 temperature rise in the working space and, due to the thermal capacity of the water, the
226 response time may be longer. This may necessitate additional cooling with possible de-
227 humidification effects.
228 If bubbles occur, they may produce a small amount of spray when bursting.
229 4.5 Surface evaporation
230 The air is humidified by passing it over a large surface area of water. Different methods are
231 used, for example repeated air flow over standing water or water-jet scrubbing over a vertical
232 surface with the air stream in counter current. In this system, the spray is minimized. The
233 humidity is controlled by changing the water temperature. Due to the thermal capacity of the
234 water, the response time may be longer.
235 4.6 Aqueous solutions
236 Relative humidity is generated over standardized aqueous solutions of salts in small, sealed
237 chambers at constant temperature. This
...