SIST EN IEC 60068-3-14:2025

SLOVENSKI STANDARD
01-november-2025
Okoljsko preskušanje - 3-14. del: Podporna dokumentacija in navodilo - Razvoj
klimatskega sekvenčnega preskušanja (IEC 60068-3-14:2025)
Environmental testing - Part 3-14: Supporting documentation and guidance - Developing
a climatic sequential test (IEC 60068-3-14:2025)
Umgebungseinflüsse – Teil 3-14: Unterstützende Dokumentation und Leitfaden –
Entwickeln einer Klima-Tests-Abfolge (IEC 60068-3-14:2025)
Essais d'environnement - Partie 3-14: Documentation d'accompagnement et
recommandations - Élaboration d'un essai climatique séquentiel (IEC 60068-3-14:2025)
Ta slovenski standard je istoveten z: EN IEC 60068-3-14:2025
ICS:
01.110 Tehnična dokumentacija za Technical product
izdelke documentation
19.040 Preskušanje v zvezi z Environmental testing
okoljem
29.020 Elektrotehnika na splošno Electrical engineering in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 60068-3-14

NORME EUROPÉENNE
EUROPÄISCHE NORM September 2025
ICS 19.040
English Version
Environmental testing - Part 3-14: Supporting documentation
and guidance - Developing a climatic sequential test
(IEC 60068-3-14:2025)
Essais d'environnement - Partie 3-14: Documentation Umgebungseinflüsse - Teil 3-14: Unterstützende
d'accompagnement et recommandations - Élaboration d'un Dokumentation und Leitfaden - Entwickeln einer Klima-
essai climatique séquentiel Tests-Abfolge
(IEC 60068-3-14:2025) (IEC 60068-3-14:2025)
This European Standard was approved by CENELEC on 2025-08-22. 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.
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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
© 2025 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60068-3-14:2025 E

European foreword
The text of document 104/1100/FDIS, future edition 1 of IEC 60068-3-14, prepared by TC 104
"Environmental conditions, classification and methods of test" was submitted to the IEC-CENELEC
parallel vote and approved by CENELEC as EN IEC 60068-3-14:2025.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2026-09-30
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2028-09-30
document have to be withdrawn
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 60068-3-14:2025 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 60068-1:2013 NOTE Approved as EN 60068-1:2014 (not modified)
IEC 60068-2 (series) NOTE Approved as EN IEC 60068-2 (series)
IEC 60721-1 NOTE Approved as EN 60721-1
IEC 60721-2 (series) NOTE Approved as EN 60721-2 (series)
IEC 60721-3 (series) NOTE Approved as EN IEC 60721-3 (series)

IEC 60068-3-14 ®
Edition 1.0 2025-07
INTERNATIONAL
STANDARD
Environmental testing –
Part 3-14: Supporting documentation and guidance – Developing a climatic
sequential test
ICS 19.040  ISBN 978-2-8327-0577-3

IEC 60068-3-14:2025-07(en)
IEC 60068-3-14:2025 © IEC 2025
CONTENTS
FOREWORD . 2
INTRODUCTION . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Background . 6
4.1 Environmental exposure sequence in life cycle . 6
4.2 Failure mechanism under a sequential test . 6
5 Introduction to the process . 6
5.1 General . 6
5.2 Stage 1: reviewing environmental requirements and compiling a provisional
test sequence . 7
5.3 Stage 2: establishing critical environments and refining sequence . 7
5.4 Stage 3: preparing sequential test programme . 7
5.5 Overall process . 8
6 Stage 1: reviewing requirements and compiling provisional test sequence . 8
6.1 Evaluating product life cycle . 8
6.2 Evaluating environmental requirements . 9
6.2.1 Identifying major phases . 9
6.2.2 Determining typical environmental conditions . 9
6.3 Compiling provisional list of critical environments . 10
7 Stage 2: establishing critical environments and refining sequence . 10
7.1 Consideration of the operational state of the product . 10
7.2 Identification of potential failure modes . 10
7.3 Identifying need for combined testing . 11
7.4 Reviewing sensitivity of product to sequential environmental conditions . 12
7.5 Consideration of sequential and non-sequential testing . 13
8 Stage 3: preparing sequential test programme . 13
8.1 General . 13
8.2 Critical climatic tests . 14
8.3 Combined climatic tests . 14
8.4 Climatic sequential tests . 15
8.5 Reviewing programme for technical credibility and cost effectiveness . 15
Annex A (informative) Failure modes . 17
A.1 General . 17
A.2 Failure modes of electrical and electronic components . 17
A.3 Failure modes of optics and sensors . 19
A.4 Failure modes of power sources . 19
Bibliography . 20

Table 1 – Process to develop an environmental test sequence . 8

IEC 60068-3-14:2025 © IEC 2025
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Environmental testing -
Part 3-14: Supporting documentation and guidance -
Developing a climatic sequential 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,
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preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
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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.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 60068-3-14 has been prepared by IEC technical committee 104: Environmental conditions,
classification and methods of test. It is an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
104/1100/FDIS 104/1124/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.
IEC 60068-3-14:2025 © IEC 2025
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, or
– revised.
IEC 60068-3-14:2025 © IEC 2025
INTRODUCTION
The IEC 60068-2 series includes a variety of single and combined climatic condition tests. Some
of these tests can give cumulative effects or hysteretic effects, causing the unit-under-test to
deteriorate, and making it more vulnerable to subsequent tests. Thus, determining the sequence
of tests has a significant influence on the conclusion of a composite test.
This subpart of IEC 60068-3 provides guidance for developing a climatic sequential test for a
certain type of product (electrical, electromechanical or electronic equipment and devices, as
well as their subassemblies, constituent parts and components). It is written for technicians,
engineers and managers in environment testing, and for those who need to understand the
results of climatic sequential tests.
With the increasing importance of the IEC Quality Assessment System for Electronic
Components (IECQ), it has become necessary to define the test sequence more precisely than
it could be done in IEC 60068-1:2013, Clause 7, in order to provide a satisfactory reproducibility
of the test. This document describes in detail a composite test specifying a "climatic sequence"
for product specimens. It includes guidance in informative annexes for specification writers and
those performing the test.
IEC 60068-3-14:2025 © IEC 2025
1 Scope
This part of IEC 60068 describes a generic process for developing a climatic sequential test
programme by sequencing test methods selected from the IEC 60068-2 series.
This generic process comprises a systematic approach to the development of a sequential
environmental test programme.
A climatic sequential test is applicable to electrical, electromechanical or electronic equipment
and devices, as well as their subassemblies, constituent parts and components. It can be
customized according to specific product requirements and applications.
The process is designed for use by product designers, manufacturers and users.
The process is particularly relevant to electrical products which include components or materials
that have the potential to degrade, as a consequence of environmental exposures.
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 terminological databases for use in standardization at the following
addresses:
– IEC Electropedia: available at http://www.electropedia.org/
– ISO Online browsing platform: available at http://www.iso.org/obp
3.1
cumulative effects
permanently remained consequences of environmental conditions imposed on a product after
the environmental exposures are removed
3.2
hysteretic effects
gradually attenuated consequences of an environmental condition after the environmental
exposure are removed
3.3
life cycle environmental profile
LCEP
design and test decision baseline document outlining real-world environmental conditions that
a product or component will experience during usage-related events from its release/
manufacturing to the end of its useful life
Note 1 to entry: Examples of usage-related events are transportation, storage, operational usage and maintenance.
IEC 60068-3-14:2025 © IEC 2025
4 Background
4.1 Environmental exposure sequence in life cycle
When exposed to environmental conditions, products can be influenced by the surrounding
environment. The influence is related to the environmental severity, the mechanism of
environmental effect on products and the initial state.
To provide confidence that a product is capable of surviving and operating in environmental
conditions which it encounter during its life cycle, it is necessary to evaluate the product against
those conditions.
As far as practicable, such evaluations should consider all environmental conditions and their
sequence the product can experience during its life cycle. An environmental test programme
should, as far as practicable, replicate the usage environment and expose the product to the
environmental conditions so that the product can experience them from the point of manufacture
to the end of its life. The environmental conditions that exist during storage, transportation,
handling and operation should be considered.
NOTE See IEC 60721-1, the IEC 60721-2 series and the IEC 60721-3 series for the classification of environmental
conditions.
4.2 Failure mechanism under a sequential test
The environmental worthiness assessment of products is generally conducted by serial
laboratory environmental tests according to a specified environmental test programme.
NOTE See the IEC 60721-4 series for guidance for the correlation and transformation of environmental condition
classes to the environmental tests.
While a specimen is exposed to one environmental test, its state changes somehow. The
changes can be some permanent damages due to the previous environment to which the
specimen exposes, or some remaining effects, which will disappear gradually in a long duration,
by the previous environmental exposure.
When an environmental test programme is to be specified for a particular product, the sequence
in which tests are carried out is important. That is because damage or effect, initiated by the
previous environmental test, is not probably become apparent or significant, until another is
applied. Specifically, a product can survive from an environmental test programme if the test is
carried out in one particular order but fail if executed in another order.
Therefore, the order in which environmental tests are undertaken should ideally reflect the order
in which they appear in the life cycle of product. In practice, it is usually not possible to exactly
reproduce every aspect of a product life cycle, as environmental exposure varies, especially
during operational conditions.
5 Introduction to the process
5.1 General
The process to develop a climatic environmental test sequence, as set out in this document,
consists of three stages:
a) stage 1: reviewing environmental requirements of products and compiling a provisional
sequence;
b) stage 2: establishing critical environments based upon knowledge and refining sequence;
c) stage 3: preparing a technically reliable, cost-effective sequential test programme.
IEC 60068-3-14:2025 © IEC 2025
5.2 Stage 1: reviewing environmental requirements and compiling a provisional test
sequence
Stage 1 of the process considers the product usage requirements to establish a provisional
environmental sequence.
Generally, the requirements of specific concerns are
– the product life cycle distinguished by several phases including transportation, storage,
installation, operation and maintenance, as well as
– the product environmental requirements, usually consisting of a set of environmental
characteristics representing each phase of the product life cycle.
Together these are used to generate a provisional list of environmental requirements and
sequence.
At this stage, the environmental sequence comprises a list of environmental conditions arising
from each phase of the product life cycle. This provisional environmental sequence will be
extensive, with many similar environmental conditions appearing within a number of different
phases, of the life cycle.
5.3 Stage 2: establishing critical environments and refining sequence
Stage 2 of the process refines the provisional environmental sequence to eliminate unnecessary
repetition of environmental conditions, as well as consider the effects of the sequence and of
potential product failure modes. The elimination of unnecessary repetition of environmental
conditions is achieved by considering the operational state. For example, the environmental
conditions occurring when the product is packaged and non-operational have the potential to
be merged.
It is possible for concurrent environmental conditions to have an effect on the product, which is
greater than the case if they are applied separately. In such cases, the concurrent
environmental conditions sometimes have a synergistic effect. If the synergistic effect is likely
to be significant for a particular product, consideration shall be given to undertake combined
environmental testing.
In parallel, consideration of the potential failure modes of the product should allow a sequential
order of the environmental conditions to be established. For example, if temperature variation
testing degrades seals and joints, allowing moisture around to pass through these seals and
joints when the product is exposed to a damp heat condition, the temperature variation test
should be done before the humidity test. Conversely, when moisture penetrates into electrical
box during the humidity test, a following low temperature test can cause the test sample to
condense or freeze inside.
It is for this reason that the recursive and iterative philosophy to refine test sequence is
generally the keyword throughout the whole process to develop a test programme.
Stage 2 of the process also distinguishes the environmental conditions which should be
considered as part of a sequential programme and those that can be considered separately, as
non-sequential tests.
5.4 Stage 3: preparing sequential test programme
Stage 3 of the process considers the environmental sequence generated by the preceding
stages and then generates a technically reliable, cost-effective test programme.
Having identified the appropriate sequences of environments, these can be converted into a
test programme.
IEC 60068-3-14:2025 © IEC 2025
This shall also consider the need to include appropriate functional testing of the product before,
during and after the testing, as well as the need for any post-test destructive or non-destructive
inspection.
In certain cases, greater technical credibility and cost effectiveness can be achieved by
modifying the sequence, to allow more effective use and time.
Although, such modifications should not override the order identified in stage 2, some
adjustments can still be achieved.
5.5 Overall process
The overall process is illustrated in Table 1 and is discussed in detail hereinafter.
Table 1 – Process to develop an environmental test sequence
Stage Task Sub-task
Evaluating life cycle
Reviewing requirements and
1 compiling a provisional test Evaluating environmental requirements
sequence
Compiling provisional lists of critical environments
Consideration of the operational state of the product
Identification of potential failure modes
Establishing critical environments Reviewing sensitivity of the product to sequential
2 based upon knowledge of product environmental conditions
and refining test sequence
Identifying need for combined testing, and refine test
programme
Consideration of sequential and non-sequential testing
Preparing a sequential test Reviewing programme for technical credibility and cost
programme effectiveness
6 Stage 1: reviewing requirements and compiling provisional test sequence
6.1 Evaluating product life cycle
Consideration of the product life cycle should have occurred as part of the exercise to generate
the environmental requirements document. The environmental requirements document should
reflect the predominant phases of the life cycle. However, a product life cycle can contain
multiple iterations of some events; for instance, the product has the potential to be transported
several times in its entire life. As a consequence, even a well-constructed environmental
requirements document should be considered alongside the life cycle, when identifying all the
sequential conditions the particular equipment experiences.
The product life cycle can also be used to identify whether changes in logistics and operational
usage will occur in the future. For example, one type of transport vehicle can be replaced by
another. Even when information of future potential environmental conditions is not known,
identifying the possibility permits the management of potential consequences. It is also
necessary to consider a worst-case usage to future proof against unknown usage requirements.
IEC 60068-3-14:2025 © IEC 2025
6.2 Evaluating environmental requirements
6.2.1 Identifying major phases
The information in the environmental requirements document can be presented in several ways.
Whichever approach is used, the logistical and operational requirements should be broken down
into their major phases. The phases can differ for each type of product, but typically consist of
the following, which reflect the layout used in other parts of this document.
a) Delivery: This phase should encompass the types of transportation to be used and the
associated worldwide regions, from which the product is delivered. The most common form
of transportation is by road, but air, rail and water transportation are sometimes also
required. Delivery is usually undertaken with the product packaged. Handling of ISO shall
be addressed.
b) Storage: The main environments of concern during long term storage are climate along with
some potential for contamination. Storage can be within conditioned or non-conditioned
buildings. Handling using forklift trucks and also manhandling, for low mass product, shall
be considered.
c) Transportation to depot: This phase should encompass the types of transportation to be
used, along with the associated worldwide regions, in which the product is transported. The
most common forms of transportation are by road, rail, air and sea. Transportation to the
depot is usually undertaken, with the packaged. Handling using forklift trucks and cranes
shall be considered.
d) Transportation beyond the depot: The environments experienced during delivery beyond the
depot can be more severe than those during delivery to the depot. In addition to road, air
and sea transportation, the product can experience off-road transportation and poor-quality
handling.
e) Short term storage: The main environments of concern during short term storage are climate
and contamination. Storage can be within conditioned or non-conditioned buildings, partially
protected (open sided) buildings, under temporary covers such as a tarpaulin or fully
exposed to climatic conditions. Poor quality handling products or manual handling can be
chosen for handling products. Packaging can be the same as for the situation of transporting
to the depot. Alternatively, it involves degraded packaging or no packaging.
f) Operation: The environmental conditions during operation, can be severe and also unique.
They can occur in conjunction with those of installation/operation. The product is likely to
be required to operate during this phase.
g) Return: In some cases, products can be returned to the depot or country of origin for storage,
repair, upgrade or disposal, etc. Returned products are possible to have been "broken out"
of its packaging during earlier phases and consequently have become contaminated.
h) Product disposal: There can be no control over the storage and transportation environmental
conditions imposed on product during the disposal phase.
6.2.2 Determining typical environmental conditions
For each phase of the logistical and operational requirements identified for particular product,
the individual environmental conditions should be specified in detail. Typical environmental
conditions, which should be encompassed, are indicated below. In each case, the information
should provide the conditions causing the environment (especially for self-induced
environments), a description of the environment and quantifiable values.
NOTE See the IEC 60721-2 series and the IEC 60721-3 series for more detailed information.
a) Mechanical environments: These environments include acceleration, vibration and shock as
well as acoustic noise, impact (drop and crane swing) and bounce, etc. The environments
can also include the mechanical loading environments, associated with handling packaged.
b) Climatic environments: These environments include temperature, humidity, solar radiation,
pressure and maybe rapid or explosive decompression, icing, thermal shock, winds, freeze-
thaw and snow load etc.
IEC 60068-3-14:2025 © IEC 2025
c) Chemical, biological and contamination environments: These environments include fungal
growth, salt, acid corrosion, dust and sand, mist and fog, driving rain, driving snow and
immersion, etc. as well as a whole range of potential chemical and biological contaminants.
d) Electrical environments: Electrical and related environments also should be considered.
e) Combined environments: For each environment, it is necessary to indicate whether it occur
in conjunction with other environments and if appropriate, the probability of their joint
occurrence.
6.3 Compiling provisional list of critical environments
The provisional environmental sequence can be deduced from the environmental requirement
and the product life cycle. At this stage, the environmental sequence will comprise a list of
groups of environmental conditions, arising from each and every phase of the product life cycle.
This list comprises provisional environmental conditions and sequence and will be extensive,
with many environmental conditions appearing, within a number of different phases of the life
cycle. The purpose of the subsequent stages is to refine this sequence and reduce any
unnecessary repetition of the environmental conditions within the test programme.
7 Stage 2: establishing critical environments and refining sequence
7.1 Consideration of the operational state of the product
To eliminate unnecessary repetition of environmental conditions in the provisional
environmental sequence, the preliminary step takes the various operational states of the
product into consideration. If the product is in the same operational state, the potential exists
to merge similar environmental conditions. Through considering in this way, a significant
reduction in the provisional environmental test sequence is usually possible. For example, many
transportation phases take place on similar platforms and are likely to occur with the product in
the same operational state (packaged and non-operating).
Similar environmental conditions, but with the product in a different operational state, cannot
usually be accumulated, unless it is shown that the environmental conditions have a similar
effect on the product.
For most products, the relevant states are likely to be: "packaged and non-operating",
"unpackaged and non-operating", "unpackaged and operating" and "re-packaged and non-
operating". Some products can have intermediate levels of packaging. This includes situations
when the product is unpackaged, but still has limited protection. Similarly, some products can
have different levels of operation/function, for example, a standby and fully operational state.
"Re-packaged and non-operating" products have been specifically included here, because the
re-packaging process can occur under poor conditions and the products can return to their
package (or another package) in a contaminated or incomplete state.
Generally, if product is non-operating, it will be expected to operate after the applicable
environmental conditions but not during. However, if product is operating, it will be expected to
meet its operational requirements, during the applicable environmental conditions as well as
after. An exception to these categories is the case of abnormal environmental conditions (e.g.
extreme normal or accidental conditions). Products that are exposed to abnormal environmental
conditions usually have specific requirements which only a few shall be considered as part of
the environmental sequential test programme. Others are considered as potential non-
sequential tests, which will be addressed later.
7.2 Identification of potential failure modes
Identifying potential failure modes of product is undertaken to allow a sequential order of the
priority of environmental conditions to be established.
IEC 60068-3-14:2025 © IEC 2025
The need to identify potential failure modes is of particular importance, when the environmental
testing is intended to demonstrate survival and function, after exposure to environmental
conditions.
The key activity for identifying potential failure modes is the examination of the design details
of products, to ascertain the potential failure modes, their subsystems and components. The
aim is to identify any sensitivity or design weaknesses of products, to specific environmental
conditions.
However, a specific design weakness should be exercised by the test and it is not a reason for
limiting the testing whether the environmental conditions stressing the weakness are likely to
be experienced in actual use or not.
The examination of product to identify failure modes should draw on the design data and
knowledge of potential failure modes from past experience of similar scenarios.
The identified failure modes of products will be used to establish a priority order, within the
environmental test sequence. They will also be used in the next stage as the basis for identifying
the consideration of combined environmental conditions.
Additional advice on some more critical product failure modes is set out in Annex A.
7.3 Identifying need for combined testing
This stage of the process takes consideration of combined environmental conditions. This is
specifically relevant when there is a possibility of exercising potential failure modes in combined
testing, as these modes will not be adequately exercised if environmental conditions are applied
separately or out of sequence.
Many environmental conditions occur in conjunction with other environmental conditions. In
either case, it is possible for the concurrent environmental conditions to have an effect on
products, which is greater than the case applied separately. The most common of these is the
effects of low air pressure and high temperature on a heat-dissipating product: each can make
the product have an additional temperature increase separately and higher increase when
combined.
The process for identifying combined conditions, worthy of consideration, should be based upon
the product failure modes, identified in 6.2. These failure modes and associated degradation
mechanisms should be reviewed, to identify which are exacerbated by two or more
simultaneously applied environmental conditions. If the effect of applying those environmental
conditions together is worse than applying them separately or the consequences on safety or
mission are significant, the use of combined environmental testing should always be considered.
It is frequently the case that, in order to undertake combined environmental testing, special test
facilities are required. Also, testing certain combined conditions can be difficult and expensive
to perform. The following provides guidance on the most commonly encountered combined
conditions.
a) The vast majority of the test procedures may be undertaken in combination with
temperature. This is because temperature can change material properties and therefore the
response to other environmental stimuli. As a consequence, environmental testing
undertaken in conjunction with temperature comprises the most common group of combined
conditions encountered. In most cases, applying environmental conditions in conjunction
with temperature is undemanding and does not unduly complicate a test or make it
unreasonably costly. Combining environmental testing with temperature in an environmental
sequential test programme can have detrimental effects if the product contains components,
which will be degraded by exposure to the high temperatures.
IEC 60068-3-14:2025 © IEC 2025
b) The effects of several environmental conditions are exacerbated in the presence of humidity.
As a consequence, several of test procedures may be undertaken in combination with
humidity (mostly high humidity levels but sometimes low). Generally, if testing is undertaken
inside a climatic chamber, to achieve a specific temperature requirement, humidity may also
be applied. A number of the test procedures intrinsically apply environmental conditions,
combined with a high humidity environment, to encourage corrosion or mould growth and to
facilitate icing.
c) Low-pressure and high-pressure testing is usually undertaken in conjunction with
temperature (mostly low temperature but sometimes high temperature). Some pressure test
procedure encompasses the combined application of both pressure and temperature.
d) The effects of wind exacerbate several environmental conditions, including rain, snow, hail,
dust and sand. In each of these cases, the appropriate test procedure may include a wind
component or its effect.
7.4 Reviewing sensitivity of product to sequential environmental conditions
Having identified potential product failure modes, it is necessary to identify the sensitivity of
those modes, to the order in which environmental conditions are applied. For example, if
exposure to temperature is possible to permanently degrade the physical properties of a
material, temperature testing should occur before mechanical testing.
In practice the vast majority of environmental conditions will generate some degradation of the
product. In many cases, the degradation is not sufficient to make the product particularly
susceptible to subsequent environmental conditions.
However, when the product is of safety or mission critical, even marginal degradation would
cause unacceptable consequences. When considering potential susceptibility to subsequent
environmental exposure, the following are worthy of consideration, but should not be considered
to be an exhaustive list.
a) The ability of seals and joints to withstand penetration by air, moisture, humidity, mould and
contaminants etc. can be degraded by the previous application of temperature testing,
especially temperature variation testing. For this reason, a temperature variation testing is
sometimes undertaken before humidity, wetting and mould growth tests.
b) Low air pressure atmosphere can extract air inside the product with a sealed but not
hermetic structure, such as packaged components and electrical boxes. Pressure inside will
decrease gradually to that outside. When the atmosphere pressure increases, the internal
pressure variation will be a hysteretic curve. There can be a pressure difference between
the interior of products and the surround atmosphere. Products can be more vulnerable to
a damp environment after being exposed to a low air pressure condition.
c) Water penetrating a product can degrade its physical properties and make it more
susceptible to subsequent physical loadings (pressure, acceleration, crushing, vibration,
shock etc.). If products are degraded by water penetration, the appropriate wetting test
should be undertaken before the low air pressure testing.
d) Water or moisture penetrating into product can subsequently freeze at cold temperatures,
causing loss of function. Similarly, recovery from a low-pressure environment can allow
water or moisture to enter and subsequently freeze at cold temperatures. A freeze-thaw test
procedure or a pressure-temperature-humidity test is necessary to apply the appropriate
conditions in an appropriate order.
e) Dust can penetrate into a product and sand can erode surface finishes. As a consequence,
products will degrade against some subsequent environmental conditions, typically,
temperature variation for penetration and moisture for corrosion. In such cases, it is
appropriate to undertake dust and sand testing, early in the unpacked phase of the
sequential testing.
IEC 60068-3-14:2025 © IEC 2025
7.5 Consideration of sequential and non-sequential testing
Not all environmental conditions shall be considered as part of an environmental test sequence.
However, it is still necessary to evaluate survival and/or function of the product against these
conditions. In such cases, those particular environmental conditions should be considered as
part of a non-sequential environmental trials programme. There are no hard and fast rule, as to
which environmental conditions are considered as part of the non-sequential, rather than the
sequential programme. Such a decisi
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