IEC 60068-3-5:2018

IEC 60068-3-5 ®
Edition 2.0 2018-01
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Environmental testing –
Part 3-5: Supporting documentation and guidance – Confirmation of the
performance of temperature chambers

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IEC 60068-3-5 ®
Edition 2.0 2018-01
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Environmental testing –
Part 3-5: Supporting documentation and guidance – Confirmation of the

performance of temperature chambers

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 19.040 ISBN 978-2-8322-5318-2

– 2 – IEC 60068-3-5:2018 RLV © IEC 2018

CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Measuring chamber performances . 9
4.1 Test area environment . 9
4.2 Temperature measurement system . 9
4.3 Temperature chamber test loads specimens . 9
4.4 Installation Specified location of temperature sensors in working space . 9
4.5 Determination of temperature performance Measurement method . 11
4.5.1 General . 11
4.5.2 Achieved temperature . 11
4.5.3 Temperature stabilization . 11
4.5.4 Temperature fluctuation . 12
4.5.5 Temperature gradient . 13
4.5.6 Temperature variation in space . 14
4.5.7 Temperature rate of change . 14
4.6 Standard temperature sequence . 15
Evaluation criteria .
5 Information to be given in the performance test report . 16
Bibliography . 17

Figure 1 – Working space . 7
Figure 2 – Example of temperature differences . 8
Figure 3 – Location of air temperature sensors for temperature chambers up to 2 000 l . 10
Figure 4 – Location of minimal additional air temperature sensors for temperature
chambers over 2 000 l . 10
Figure 5 – Example of achieved temperature . 11
Figure 6 – Example of temperature stabilization for chambers up to 2 000 l . 12
Figure 7 – Example of temperature fluctuation . 12
Figure 8 – Example of temperature gradient for chambers up to 2 000 l . 13
Figure 9 – Example of temperature gradient for chambers <2 000 L . 14
Figure 10 – Example of temperature rate of change for heating and cooling of a test
chamber . 15

Table 1 – Practical dimensions . 8

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ENVIRONMENTAL TESTING –
Part 3-5: Supporting documentation and guidance –
Confirmation of the performance of temperature chambers

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition. A vertical bar appears in the margin wherever a change
has been made. Additions are in green text, deletions are in strikethrough red text.

– 4 – IEC 60068-3-5:2018 RLV © IEC 2018
International Standard IEC 60068-3-5 has been prepared by IEC technical committee 104:
Environmental conditions, classification and methods of test.
This second edition cancels and replaces the first edition published in 2001. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Confirmation procedures are clarified.
The text of this International Standard is based on the following documents:
FDIS Report on voting
104/759/FDIS 104/778/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60068 series, published under the general title Environmental
testing, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The “colour inside” logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this publication using a colour printer.

INTRODUCTION
IEC 60068 (all parts) contains fundamental information on environmental testing procedures
and severities.
The expression "environmental conditioning" or "environmental testing" covers the natural and
artificial environments to which components or equipment may be exposed so that an
assessment can be made of their performance under conditions of use, transport and storage
to which they may be exposed in practice.
Temperature chambers used for "environmental conditioning" or "environmental testing" are
not described in any publication, although the method of maintaining and measuring
temperature and/or humidity has a great influence on test results. The physical characteristics
of temperature chambers can also influence test results.

– 6 – IEC 60068-3-5:2018 RLV © IEC 2018
ENVIRONMENTAL TESTING –
Part 3-5: Supporting documentation and guidance –
Confirmation of the performance of temperature chambers

1 Scope
This part of IEC 60068 provides a uniform and reproducible method of confirming that
temperature test chambers, without load specimens, conform to the requirements specified in
climatic test procedures of IEC 60068-2 (all parts) and other standards. This document is
intended for users when conducting regular chamber performance monitoring.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements 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 60068-1, Environmental testing – Part 1: General and guidance
IEC 60068-2 (all parts), Environmental testing – Part 2: Tests
IEC 60068-3-6, Environmental testing – Part 3-6: Supporting documentation and guidance –
Confirmation of the performance of temperature/humidity chambers
IEC 60068-3-7, Environmental testing – Part 3-7: Supporting documentation and guidance –
Measurements in temperature chambers for tests A and B (with load)
IEC 60068-3-11, Environmental testing – Part 3-11: Supporting documentation and guidance
– Calculation of uncertainty of conditions in climatic test chambers
IEC 60584-1, Thermocouples – Part 1: Reference tables
IEC 60751, Industrial platinum resistance thermometer sensors
ISO 10012-1, Quality assurance requirements for measuring equipment – Part 1: Metrological
confirmation system for measuring equipment
ISO 10012-2, Quality assurance for measuring equipment – Part 2: Guidelines for control of
measurement processes
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
temperature test chamber
enclosure or space in some parts of which the temperature conditions, specified in
IEC 60068-2 (all parts), can be achieved
3.2
temperature setpoint
desired temperature as set by the chamber controls
3.3
achieved temperature
stabilized temperature in the chamber at any point within the working space after stabilization
which desired temperature at the centre of the working space achieves within specified
tolerance
3.4
temperature stabilization
temperature at which all points in the working space have reached and maintained the
setpoint temperature within a given tolerance state of maintaining temperature within
specified tolerance during specified time at specified points in the working space
3.5
temperature fluctuation
difference, after stabilization, between the maximum and minimum temperatures at any
specified point in the working space during a specified interval of time
Note 1 to entry: For calibration, the centre point of working space may be used.
3.6
working space
part of the chamber in which the specified conditions can be maintained within the specified
tolerances
Note 1 to entry: See Figure 1 and Table 1.
X
L
X
X X
1 2
X X
1 2
L
L
IEC
Figure 1 – Working space
– 8 – IEC 60068-3-5:2018 RLV © IEC 2018
Table 1 – Practical dimensions
Size Volume Distance X X (min.)
l mm mm
Small Up to 1 000 L/10 50
Medium 1 000 to 2 000 L/10 100
Large More than 2 000 L/10 150
NOTE Not all chambers are cubic in construction.

3.7
temperature gradient
maximum difference in mean value, after stabilization, at any moment in time between two
separate points in the working space
3.8
temperature variation in space
difference in mean value, after stabilization, at any moment in time between the temperature
at the centre of the working space and at any other point in the working space
3.9
temperature rate of change
rate, in degrees kelvin per minute, for the transition between two specified temperatures
measured at the centre of the working space
Note 1 to entry: See Figure 2.
Temperature fluctuation
outside the centre of
working space (see 3.5)
Temperature fluctuation
in the centre of
working space (see 3.6)
Temperature fluctuation
outside the centre of
working space (see 3.5)
Time
IEC
Figure 2 – Example of temperature differences
3.10
temperature extremes
maximum and minimum measured temperatures achieved in the working space after
stabilization
Temperature
Variation
(see 3.8)
Gradient
(see 3.7)
4 Measuring chamber performances
4.1 Test area environment
The environment around a temperature test chamber may influence the conditions inside the
test chamber.
The confirmation of performance of temperature chambers should be carried out under
standard atmospheric conditions specified in IEC 60068-1.
The following items should be taken into consideration:
– the ambient conditions described in IEC 60068-1 should be satisfied in principle;
– the chamber should not be exposed to direct solar radiation;
– the chamber should not be exposed to electromagnetic interference;
– the chamber should be levelled;
– the chamber should be fixed in a location free from any mechanical and acoustic vibration
interference.
Manufacturer's advice on electrical power requirements and the environmental conditions
should be taken into consideration.
Abnormal conditions should be recorded.
4.2 Temperature measurement system
The uncertainty of measurement of the output of the measurement system should be
determined by calibration of the system, traceable to international standards (see ISO 10012-
1 and ISO 10012-2).
Normally sensors should be either the resistance type (in accordance with IEC 60751) or the
thermocouple type (in accordance with IEC 60584-1). The 50 % response time in air of the
sensor shall be between 10 s and 40 s. The response time of the overall system should be
less than 40 s.
In a temperature range from –200 °C to +200 °C the sensor measurement uncertainty should
be in accordance with class A of IEC 60751.
The temperature sensors may be either calibrated platinum resistors or a thermocouple. The
thermal response time of the sensors shall be within a minimum of 10 s and a maximum of
40 s for 50 % of response. It is preferred that the thermal response time of the entire
measurement system to be less than 40 s. The use of sensors that are compliant to
IEC 60584-1 tolerance class 1 (for thermocouples) or IEC 60751 tolerance class A (for
resistors) is recommended.
4.3 Temperature chamber test load specimens
All measurements described in 4.5 are performed with an empty working space. If it is not
possible to empty the chamber totally this should be recorded. For measuring with test load
specimens (with or without heat dissipation), see IEC 60068-3-7.
4.4 Installation Specified location of temperature sensors in working space
Temperature measuring sensors are located in each corner and in the centre of the working
space (see Figure 3, minimum 9 sensors). For temperature chambers over 2 000 l, additional
sensors should be located in front of the centre of each wall (see Figure 4, minimum
15 sensors). The measuring system is to be arranged in such a way that the temperature

– 10 – IEC 60068-3-5:2018 RLV © IEC 2018
distribution of the empty test chamber will not be affected. For a large capacity chamber,
there may be a significant difference between the temperature control sensor(s) and the
temperature at the centre of the working space. It may be necessary to adjust the temperature
setting to achieve the necessary tolerance.
Recording of the achieved temperature should be effected.
N
N
L
3 N
N
Centre
N
L
N
N
N
L
N
L
L
L
L
L
L
IEC
Figure 3 – Location of air temperature sensors for
temperature chambers up to 2 000 l
X
X
IEC
Figure 4 – Location of minimal additional air temperature sensors for
temperature chambers over 2 000 l
For confirmation monitoring, data should be recorded at least once a minute. The device used
for recording data from the chamber monitoring sensors should be independent of the
chamber control system.
X
4.5 Determination of temperature performance Measurement method
4.5.1 Achieved temperature, temperature fluctuation, temperature variation in space,
temperature gradient
The output of the temperature measuring system (see figure 3 or figure 4) determine, after
chamber stabilization, the achieved temperature, temperature fluctuation and temperature
gradient of the working space. Uncertainty of measurement of the temperature measuring
system should be taken into account and the allowable tolerance reduced by the magnitude of
the uncertainty.
4.5.1 General
The temperature output of the temperature measuring system (see Figure 3 or Figure 4)
determines, after chamber stabilization, the achieved temperature, temperature fluctuation
and temperature gradient of the working space. For tolerance, the specification of the
temperature/humidity chamber or, as necessary, tolerance specified in IEC 60068-2 (all parts),
is required to maintain at the centre of the working space. Location of sensor is minimum 9
points or 15 points. This depends on the test chamber size. The measurement method is
explained based on 9 points.
Uncertainty of measurement of the temperature measuring system shall be according to
IEC 60068-3-11.
4.5.2 Achieved temperature
Temperature is achieved when the centre of the working space maintains the tolerance as
required by IEC 60068-2 (all parts). An example is shown in Figure 5.
T
N
Tolerance
Temperature
setting
IEC
For tolerance, check the specification of the temperature chamber, or, as necessary, use tolerance specified in
IEC 60068-2 which is required to maintain at the centre of the working space.
T must be minimum 30 min. N is the temperature at the centre of the working space.
Figure 5 – Example of achieved temperature
4.5.3 Temperature stabilization
Temperature reached and maintained within the allowable range in the working space is
shown in Figure 6. Allowable range is based on the temperature fluctuation, temperature
variation in space, and temperature gradient as the temperature chamber specification.

– 12 – IEC 60068-3-5:2018 RLV © IEC 2018
Specified time T is minimum 30 min after the measurement points (e.g. N to N ) are within
2 1 9
the allowable range.
T
N
Allowable
range
N
IEC
Figure 6 – Example of temperature stabilization for chambers up to 2 000 l
4.5.4 Temperature fluctuation
The fluctuation during a specified interval of time at specified temperature points in the
working space, after temperature stabilization, is shown in Figure 7.
N
Max
+2σ
n–1
+1σ
n–1
–1σ
n–1
Average
temperature N
Ave
σ
n–1
Specimen standard
deviation
–2σ
n–1
N
Min
0 5 10 15 20 25 30
Time (min)
IEC
Figure 7 – Example of temperature fluctuation

Measurements are actually made at a certain sampling interval. It is not guaranteed that data
captures the fluctuation peak. For that reason, the sample standard deviation, 𝜎 shall be
𝑛−1
obtained from the data measured in each measurement point after temperature has stabilized,
and the temperature fluctuation shall be within ±2𝜎 .
𝑛−1
The temperatures measured in a certain measurement point, after stabilization, over a
30-minute period 10 or more times at even intervals shall be as follows.
N , N , … , N , …  N (n≧10)
1 2 i n
The mean of N shall be N .
Ave
The specimen standard deviation, 𝜎 shall be defined as follows.
𝑛−1
∑(𝑋−𝑁 )
𝑖 𝐴𝐴𝐴
�
𝜎 =
𝑛−1
𝑛−1
Temperature fluctuation ±2𝜎 shall be obtained in all 9 measurement points, and the highest
𝑛−1
value within that shall be annotated as the temperature fluctuation.
4.5.5 Temperature gradient
As shown in Figure 8, the maximum difference in mean temperature in all measurement points
of the effective space shall be the temperature gradient.
N
AveMax
N
AveMin
0 5 10 15 20 25 30
Time (min)
IEC
N : Mean highest temperature in each of 9 measurement points
AveMax
N : Mean lowest temperature in each of 9 measurement points
AveMin
Temperature gradient = N – N
AveMax AveMin
Figure 8 – Example of temperature gradient for chambers up to 2 000 l

Temperature gardient
– 14 – IEC 60068-3-5:2018 RLV © IEC 2018
4.5.6 Temperature variation in space
As shown in Figure 9, temperature variation in space is the difference of the mean
temperature at the centre of the working space and the mean temperature of another
measurement point. The maximum difference between the centre of the working space and
each measuring point shall be stated.

N
CornerAve
N
CenterAve
N
CornerAve
0 5 15 20 25 30
Time (min)
IEC
N : Mean temperature at chamber center
CenterAve
N j=1 to 8: Mean temperature at corner of working space
CornerAve(j)
Temperature variation in space =｜Max(N – N )｜
CornerAve[j] CenterAve
The value obtained as the temperature variation in space shall be (N – N ), and the absolute value
CornerAve(j) CenterAve
of the highest difference obtained for the 8 corners shall be annotated as the temperature variation in space
Figure 9 – Example of temperature gradient for chambers <2 000 L
4.5.7 Temperature rate of change
As shown in Figure 10, temperature rate of change between specified temperatures shall be
calculated with the following method, and indicated in K/min.
Temperature heat-up rate = Δt/T
１
Temperature cool-down rate = Δt/T
Temperature variation in space

Heat-up Cool-down
Time T Time T
1 2
Highest
100 %
temperature
90 %
10 %
Lowest
0 %
temperature
IEC
Figure 10 – Example of temperature rate of change
for heating and cooling of a test chamber
To determine measure temperature rate of change:
• adjust chamber to lowest specified temperature and allow to stabilize;
• adjust chamber to highest specified temperature, monitoring the time between the 10 %
and the 90 % points of the temperature range;
• allow chamber to stabilize at the highest specified temperature;
• adjust chamber to lowest specified temperature, monitoring the time between the 90 %
and 10 % points of temperature range.
This will determine the temperature rates of change for heating and cooling in K/min.
4.6 Standard temperature sequence
The following test sequence is considered to be the minimum recommended to obtain the
necessary data for confirmation of the performance of a temperature chamber.
Test area conditions should be in accordance with 4.1 of this standard. The test sequence is
as follows:
• start at ambient conditions;
• adjust chamber to highest specified temperature and allow chamber to stabilize;
• measure performance at highest temperature;
• adjust chamber to lowest specified temperature, monitoring rate of change and allow
chamber to stabilize;
• measure performance at lowest temperature;
• adjust chamber to highest specified temperature, monitoring rate of change;
• adjust chamber to atmospheric conditions and allow chamber to stabilize;
• measure performance at atmospheric conditions.

∆t
– 16 – IEC 60068-3-5:2018 RLV © IEC 2018
6 Evaluation criteria
The performance of the temperature test chamber is confirmed if all results are within the
specification limits of relevant IEC 60068-2 standards.
5 Information to be given in the performance test report
As a minimum, the following information shall be contained in the test report.
– Temperature extremes.
– Any deviations such as overshoot.
– Test load if any.
a) Atmospheric conditions in the test area for measurement.
b) Size and volume of chamber enclosure and working space.
c) Temperature fluctuation, temperature variation in space and temperature gradient at each
temperature stage of clause 5.
d) Temperature rate of change, heating and cooling.
e) Highest/Lowest temperature.
f) Measurement results from each measurement position.
g) Details of data acquisition systems.
h) Evaluation of Measurements uncertainties.
i) Fixtures used for measurement.

Bibliography
IEC 60068-1, Environmental testing – Part 1: General and guidance
IEC 60068-3-6, Environmental testing – Part 3-6: Supporting documentation and guidance –
Confirmation of the performance of temperature/humidity chambers
IEC 60584-1, Thermocouples – Part 1: EMF specifications and tolerances
IEC 60751, Industrial platinum resistance thermometers and platinum temperature sensors
ISO 10012, Measurement management systems – Requirements for measurement processes
and measuring equipment
___________
IEC 60068-3-5 ®
Edition 2.0 2018-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Environmental testing –
Part 3-5: Supporting documentation and guidance – Confirmation of the
performance of temperature chambers

Essais d’environnement –
Partie 3-5: Documentation d’accompagnement et guide – Confirmation des
performances des chambres d’essai en température

– 2 – IEC 60068-3-5:2018 © IEC 2018
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Measuring chamber performances . 8
4.1 Test area environment . 8
4.2 Temperature measurement system . 8
4.3 Temperature chamber test specimens . 8
4.4 Specified location of temperature sensors in working space . 9
4.5 Measurement method . 10
4.5.1 General . 10
4.5.2 Achieved temperature . 10
4.5.3 Temperature stabilization . 10
4.5.4 Temperature fluctuation . 11
4.5.5 Temperature gradient . 12
4.5.6 Temperature variation in space . 12
4.5.7 Temperature rate of change . 13
4.6 Standard temperature sequence . 14
5 Information to be given in the performance test report . 14
Bibliography . 16

Figure 1 – Working space . 7
Figure 2 – Example of temperature differences . 8
Figure 3 – Location sensors for temperature chambers up to 2 000 l . 9
Figure 4 – Location of minimal additional sensors for temperature chambers
over 2 000 l . 9
Figure 5 – Example of achieved temperature . 10
Figure 6 – Example of temperature stabilization for chambers up to 2 000 l . 11
Figure 7 – Example of temperature fluctuation . 11
Figure 8 – Example of temperature gradient for chambers up to 2 000 l . 12
Figure 9 – Example of temperature gradient for chambers <2 000 L . 13
Figure 10 – Example of temperature rate of change . 14

Table 1 – Practical dimensions . 7

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ENVIRONMENTAL TESTING –
Part 3-5: Supporting documentation and guidance –
Confirmation of the performance of temperature chambers

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60068-3-5 has been prepared by IEC technical committee 104:
Environmental conditions, classification and methods of test.
This bilingual version (2019-05) corresponds to the monolingual English version, published in
2018-01.
This second edition cancels and replaces the first edition published in 2001. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Confirmation procedures are clarified.

– 4 – IEC 60068-3-5:2018 © IEC 2018
The text of this International Standard is based on the following documents:
FDIS Report on voting
104/759/FDIS 104/778/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
The French version of this standard has not been voted upon.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60068 series, published under the general title Environmental
testing, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
INTRODUCTION
IEC 60068 (all parts) contains fundamental information on environmental testing procedures
and severities.
The expression "environmental conditioning" or "environmental testing" covers the natural and
artificial environments to which components or equipment may be exposed so that an
assessment can be made of their performance under conditions of use, transport and storage
to which they may be exposed in practice.
Temperature chambers used for "environmental conditioning" or "environmental testing" are
not described in any publication, although the method of maintaining and measuring
temperature and/or humidity has a great influence on test results. The physical characteristics
of temperature chambers can also influence test results.

– 6 – IEC 60068-3-5:2018 © IEC 2018
ENVIRONMENTAL TESTING –
Part 3-5: Supporting documentation and guidance –
Confirmation of the performance of temperature chambers

1 Scope
This part of IEC 60068 provides a uniform and reproducible method of confirming that
temperature test chambers, without specimens, conform to the requirements specified in
climatic test procedures of IEC 60068-2 (all parts) and other standards. This document is
intended for users when conducting regular chamber performance monitoring.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements 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 (all parts), Environmental testing – Part 2: Tests
IEC 60068-3-7, Environmental testing – Part 3-7: Supporting documentation and guidance –
Measurements in temperature chambers for tests A and B (with load)
IEC 60068-3-11, Environmental testing – Part 3-11: Supporting documentation and guidance
– Calculation of uncertainty of conditions in climatic test chambers
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
temperature test chamber
enclosure or space in some parts of which the temperature conditions, specified in
IEC 60068-2 (all parts), can be achieved
3.2
temperature setpoint
desired temperature as set by the chamber controls
3.3
achieved temperature
stabilized temperature which desired temperature at the centre of the working space achieves
within specified tolerance
3.4
temperature stabilization
state of maintaining temperature within specified tolerance during specified time at specified
points in the working space
3.5
temperature fluctuation
difference, after stabilization, between the maximum and minimum temperatures at specified
point in the working space during a specified interval of time
Note 1 to entry: For calibration, the centre point of working space may be used.
3.6
...