IEC 60068-2-27:2008

IEC 60068-2-27
Edition 4.0 2008-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
Environmental testing –
Part 2-27: Tests – Test Ea and guidance: Shock

Essais d'environnement –
Partie 2-27: Essais – Essai Ea et guide: Chocs

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IEC 60068-2-27
Edition 4.0 2008-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
Environmental testing –
Part 2-27: Tests – Test Ea and guidance: Shock

Essais d'environnement –
Partie 2-27: Essais – Essai Ea et guide: Chocs

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
W
CODE PRIX
ICS 19.040 ISBN 2-8318-9628-2
– 2 – 60068-2-27 © IEC:2008
CONTENTS
FOREWORD.4
INTRODUCTION.6

1 Scope.7
2 Normative references.7
3 Terms and definitions .8
4 Description of test apparatus .9
4.1 Required characteristics .9
4.2 Measuring system.11
4.3 Mounting .12
5 Severities .13
6 Preconditioning.14
7 Initial measurements and functional performance test .15
8 Testing .15
9 Recovery .15
10 Final measurements .15
11 Information to be given in the relevant specification.15
12 Information to be given in the test report .16

Annex A (normative) Selection and application of pulse shapes – Guidance.17
Annex B (informative) Shock response spectra and other characteristics of pulse
shapes.27
Annex C (informative) Comparison between impact tests.36

Bibliography .37

Figure 1 – Pulse shape and limits of tolerance for half-sine pulse .10
Figure 2 – Pulse shape and limits of tolerance for final-peak saw-tooth pulse.10
Figure 3 – Pulse shape and limits of tolerance for trapezoidal pulse.11
Figure 4 – Frequency characteristics of the overall measuring system .12
Figure A.1 – Shock response spectrum of a symmetrical half-sine pulse.19
Figure A.2 – Shock response spectrum of a final-peak saw-tooth pulse .20
Figure A.3 – Shock response spectrum of a symmetrical trapezoidal pulse .21
Figure B.1 – Framework or box containing oscillatory systems of which f , f and f are
1 2 3
examples of resonance frequencies .27
Figure B.2a – Exciting pulse.29
Figure B.2b – Responses for f , f and f .29
1 2 3
Figure B.2c – Spectra which result from an infinite number of frequencies, with f , f and
1 2
f shown as finite points on the continuous curves.29
Figure B.2 – Shock response spectrum concept .29
Figure B.3 – Framework containing damped multi-degree-of-freedom system .31
Figure B.4 – Shock response spectrum of a half-sine pulse with ripple.33

60068-2-27 © IEC:2008 – 3 –
Figure B.5 – Spectrum of a final-peak saw-tooth 300 m/s , 18 ms pulse compared with
the spectra of 200 m/s half-sine pulses with durations between 3 ms and 20 ms .35

Table 1 – Severities for shock testing .14
Table A.1 – Examples of pulse shapes and test severities typically employed for various
applications.23
Table A.2 – Examples of severities typically employed for various applications .24

– 4 – 60068-2-27 © IEC:2008
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ENVIRONMENTAL TESTING –
Part 2-27: Tests – Test Ea and guidance: Shock

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 60068-2-27 has been prepared by IEC technical committee 104:
Environmental conditions, classification and methods of test
This fourth edition cancels and replaces the third edition, published in 1987, and includes the
merging of IEC 60068-2-29, second edition (1987). It constitutes a technical revision.
The major changes with regard to the previous edition concern:
− the merging of IEC 60068-2-29 into this edition of IEC 60068-2-27; Part 2-29 will be
withdrawn as soon as this edition is published;
− the introduction of soft packaged specimens as defined in the IEC ad hoc working group
document agreed in Stockholm:2000.

60068-2-27 © IEC:2008 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
104/448/FDIS 104/457/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 is to be used in conjunction with IEC 60068-1.
A list of all the parts in the IEC 60068 series, under the general title Environmental testing, can
be found on the IEC website.
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.
– 6 – 60068-2-27 © IEC:2008
INTRODUCTION
This part of IEC 60068 deals with components, equipments and other electrotechnical
products, hereinafter referred to as “specimens”, which, during transportation, storage and
handling, or in use, may be subjected either to conditions involving relatively infrequent non-
repetitive or repetitive shocks. The shock test may also be used as a means of establishing the
satisfactory design of a specimen in so far as its structural integrity is concerned and as a
means of quality control. It consists of subjecting a specimen either to non-repetitive or
repetitive shocks of standard pulse shapes with specified peak acceleration and duration.
Specification writers will find a list of details to be considered for inclusion in specifications in
Clause 11. The necessary guidance is given in Annex A.

60068-2-27 © IEC:2008 – 7 –
ENVIRONMENTAL TESTING –
Part 2-27: Tests – Test Ea and guidance: Shock

1 Scope
This part of IEC 60068 provides a standard procedure for determining the ability of a specimen
to withstand specified severities of non-repetitive or repetitive shocks.
The purpose of this test is to reveal mechanical weakness and/or degradation in specified
performances, or accumulated damage or degradation caused by shocks. In conjunction with
the relevant specification, this may be used in some cases to determine the structural integrity
of specimens or as a means of quality control (see Clause A.2).
This test is primarily intended for unpackaged specimens and for items in their transport case
when the latter may be considered to be part of the specimen. If an item is to be tested
unpackaged, it is referred to as a test specimen. However, if the item is packaged, then the
item itself is referred to as a product and the item and its packaging together are referred to as
a test specimen. When used in conjunction with IEC 60068-2-47, this standard may be used for
testing packaged products. This possibility was included in the 2005 version of IEC 60068-2-47
for the first time.
This standard is written in terms of prescribed pulse shapes. Guidance for the selection and
application of these pulses is given in Annex A and the characteristics of the different pulse
shapes are discussed in Annex B.
Wherever possible, the test severity and the shape of the shock pulse applied to the specimen
should be such as to reproduce the effects of the actual transport or operational environment
to which the specimen will be subjected, or to satisfy the design requirements if the object of
the test is to assess structural integrity (see Clauses A.2 and A.4).
For the purposes of this test, the specimen is always mounted to the fixture or the table of the
shock testing machine during testing.
NOTE The term “shock testing machine” is used throughout this standard, but other means of applying pulse
shapes are not excluded.
One of the responsibilities of a technical committee is, wherever applicable, to make use of
basic safety publications in the preparation of its publications.
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 60068-1, Environmental testing – Part 1: General and guidance
IEC 60068-2-47:2005, Environmental testing – Part 2-47: Tests – Mounting of specimens for
vibration, impact and similar dynamic tests
IEC 60068-2-55, Environmental testing – Part 2-55: Tests – Test Ee and guidance: Bounce

– 8 – 60068-2-27 © IEC:2008
IEC 60721-3-1, Classification of environmental conditions – Part 3: Classification of groups of
environmental parameters and their severities – Section 1: Storage
IEC 60721-3-5, Classification of environmental conditions – Part 3: Classification of groups of
environmental parameters and their severities – Section 5: Ground vehicle installations
Guide 104, The preparation of safety publications and the use of basic safety publications and
group safety publications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
[1]
NOTE The terms used are, for the most part, defined in ISO 2041 or IEC 60068-1. The following additional
terms and definitions are also applicable for the purposes of this standard.
3.1
check point
point located on the fixture, on the table surface of the shock-testing machine or on the
specimen as close as possible to the fixing point, and in any case rigidly connected to it
NOTE 1 A number of check points are used as a means of ensuring that the test requirements are satisfied.
NOTE 2 If more than four fixing points exist, the relevant specification should state the number of fixing points to
be used as check points.
NOTE 3 In special cases, for example, for large or complex specimens, the check points will be prescribed by the
relevant specification if not close to the fixing points.
NOTE 4 Where a large number of small specimens are mounted on one fixture, or in the case of a small specimen
where there are a number of fixing points, a single check point (that is the reference point) may be selected for the
derivation of the control signal. This signal is then related to the fixture rather than to the fixing points of the
specimen(s). This procedure is only valid when the lowest resonance frequency of the loaded fixture is well above
the upper frequency of the test.
3.2
fixing point
part of the specimen in contact with the fixture or the table of the shock-testing machine at a
point where the specimen is normally fastened in service
NOTE If a part of the real mounting structure is used as the fixture, the fixing points are taken as those of the
mounting structure and not of the specimen.
3.3
g
n
standard acceleration due to the earth's gravity, which itself varies with altitude and
geographical latitude
NOTE For the purposes of this standard, the value of g is rounded up to the nearest unity, that is 10 m/s .
n
3.4
repetition rate
number of shocks per second
3.5
shock severity
combination of the peak acceleration, the duration of the nominal pulse and the number of
shocks
___________
Figures in square brackets refer to the bibliography.

60068-2-27 © IEC:2008 – 9 –
3.6
velocity change
absolute value of the sudden change of velocity resulting from the application of the specified
acceleration
NOTE The change of velocity is normally considered sudden if it takes place in a time that is short compared with
the fundamental period of the test specimen.
4 Description of test apparatus
4.1 Required characteristics
When the shock-testing machine with or without fixture is loaded with the specimen, the
waveform measured at the check point(s) shall consist of a pulse approximating to one of the
nominal acceleration against time curves given by the broken lines in Figures 1, 2 and 3.
4.1.1 Basic pulse shapes
Three types of pulse, namely the half-sine pulse, the final-peak saw-tooth pulse and the
trapezoidal pulse, are included in this standard. The choice of pulse shape depends on a
number of factors, and the difficulties inherent in making such a choice preclude a preferred
order being given in this standard (see Clause A.3).
The specified basic pulse shapes are given below (see Clause A.3):
− half-sine: one half-cycle of a sine wave, as shown in Figure 1;
− final-peak saw-tooth: asymmetrical triangle with short fall time, as shown in Figure 2;
− trapezoidal: symmetrical trapezoid with short rise and fall times, as shown in Figure 3.
The true value of the actual pulse shall be within the limits of tolerance shown by the solid lines
in the relevant figure.
NOTE Where it is not practicable to achieve a pulse shape falling within the specified tolerance, the relevant
specification should state the alternative procedure to be applied (see Clause A.5).

– 10 – 60068-2-27 © IEC:2008
Integration time
1,5 D
1,2 A
A
0,8 A
+0,2 A
0,2 A  0,2 A
0  0
–0,2 A –0,2 A
0,4 D 0,1 D
D D
2,5 D 2,5 D
2,4 D = T
6 D = T
IEC  303/08
Key (applicable for all three Figures 1 to 3)
– – – nominal pulse A = peak acceleration of nominal pulse
limits of tolerance T = minimum time during which the pulse shall be monitored for
shocks produced using a conventional shock-testing machine
D = duration of nominal pulse T = minimum time during which the pulse shall be monitored for
shocks produced using a vibration generator
Figure 1 – Pulse shape and limits of tolerance for half-sine pulse
Integration time
1,5 D
1,2 A
A
0,8 A
0,2 A  0,2 A
0  0
–0,2 A –0,2 A
0,4 D 0,1 D
0,1 D
D D
2,5 D 2,5 D
2,4 D = T
6 D = T
IEC  304/08
Figure 2 – Pulse shape and limits of tolerance for final-peak saw-tooth pulse

60068-2-27 © IEC:2008 – 11 –
Integration time
1,5 D
0,1 D 0,1 D
1,2 A
A
0,8 A
0,4 A
0,4 A
0,2 A  0,2 A
0  0
–0,2 A –0,2 A
0,4 D D D
2,5 D 2,5 D
2,4 D = T
6 D = T
IEC  305/08
Figure 3 – Pulse shape and limits of tolerance for trapezoidal pulse
4.1.2 Repetition rate
The repetition rate shall be such that the relative motion within the specimen between shocks
shall be substantially zero and the value of acceleration at the check point shall be within the
limits shown in Figure 1 (see Clause A.7).
NOTE A formula for evaluation of repetition rate is shown in Clause A.7.
4.1.3 Velocity change tolerances
For all pulse shapes, the actual velocity change shall be within ±15 % of the value
corresponding to the nominal pulse.
Where the velocity change is determined by integration of the actual acceleration pulse, this
shall be effected from 0,4 D before the pulse to 0,1 D beyond the pulse, where D is the
duration of the nominal pulse.
NOTE If the velocity change tolerance cannot be achieved without the use of elaborate facilities, the relevant
specification should state the alternative procedure to be adopted (see Clauses A.5 and A.6).
4.1.4 Cross axis motion
The positive or negative peak acceleration at the check point(s), perpendicular to the intended
shock direction, shall not exceed 30 % of the value of the peak acceleration of the nominal
pulse in the intended direction, when determined by 4.2.
NOTE If the cross axis motion tolerance cannot be achieved, the relevant specification should state the alternative
procedure to be adopted (see Clause A.5).
4.2 Measuring system
The characteristics of the measuring system shall be such that it can be determined that the
true value of the actual pulse, as measured above, in the intended direction at the
checkpoint(s) is within the tolerances required by the Figures 1, 2 and 3.
The requirements of Figure 4 apply to the frequency response of the measuring system without
the use of a low-pass filter on the control signal. When a low-pass filter is used, the
characteristics of the filter should be such that its cut-off frequency f (–3 dB point) is not lower
g
than:
– 12 – 60068-2-27 © IEC:2008
15,
f =
g
D
where
f is the cut-off frequency of a low-pass filter in kHz;
g
D is the pulse duration in ms.
The frequency response of the overall measuring system, which includes the accelerometer,
can have a significant effect on the accuracy and shall be within the limits shown in Figure 4
(see also Clause A.5).
+1 dB
0 dB
–1 dB
24 dB octave
–10 dB
Frequency Hz
f f f f
1 2 3 4
IEC  306/08
Duration of Low-frequency High-frequency Frequency beyond which the response
pulse cut-off cut-off may rise above +1 dB
ms Hz kHz kHz
f f f f
1 2 3 4
0,2 and 0,3 20 120 20 40
0,5 10 50 15 30
1 4 20 10 20
2and 3 2 10 5 10
6 1 4 2 4
11 0,5 2 1 2
16, 18 and 30 0,2 1 1 2
NOTE For shocks of duration equal to or less than 0,5 ms, the value of f and f indicated in Figure 4 may be
3 4
unnecessarily high. In such instances, the relevant specification should state which alternative values are to be
adopted.
Figure 4 – Frequency characteristics of the overall measuring system
4.3 Mounting
The specimen shall be mounted on the table of the shock-testing machine or fixture in
accordance with IEC 60068-2-47.

60068-2-27 © IEC:2008 – 13 –
5 Severities
The relevant specification shall prescribe the pulse shape and the shock severity. Shocks shall
be applied in all three axes and in both a positive and negative direction, as required by the
relevant specification. The effects of gravity shall be considered when considering the attitude
of the test. Unless real usage conditions are known or otherwise specified, one of the pulse
shapes given in 4.1.1 and a severity shown on the same line in Table 1 shall be used. The
preferred combinations are in bold. The corresponding velocity changes are also given in
Table 1.
The number of shocks in each direction may be chosen from the following values:
3 ± 0
100 ± 5
500 ± 5
1 000 ± 10
5 000 ± 10
NOTE If the effects of the known environment on the specimen cannot be reproduced by severities given here, the
relevant specification may prescribe an appropriate severity using one of the standard pulse shapes, shown in
Figures 1, 2 and 3 (see also Clause A.4).

– 14 – 60068-2-27 © IEC:2008
Table 1 – Severities for shock testing

Final-peak
Corresponding
Half-sine
saw-tooth Trapezoidal
duration of the
Peak Foot-
nominal pulse –3 –3 –3
notes
acceleration ΔV = 2 /π AD × 10 ΔV = 0,5 AD × 10 ΔV = 0,9 AD × 10

(A) (D)
m/s g ms m/s m/s m/s
n
a
50 5 6 0,2 0,2 0,3
50 5 30 1 0,8 1,4
60 6 11 0,4 0,3 0,6
b
100 10 16 1 0,8 1,4
100 10 11 0,7 0,6 1
c
100 10 6 0,4 0,3 0,5
150 15 6 0,6 0,5 0,8
c
150 15 11 1,1 0,8 1,5
1,1
200 20 11 1,4 2 b
250 25 6 1 0,8 1,4
c
300 30 6 1,1 0,9 1,6
300 30 18 3,4 2,7 4,9
400 40 6 1,5 1,2 2,2
c
400 40 11 2,8 2,2 4
500 50 3 1 0,8 1,4
500 50 11 3,5 2,8 5
800 80 6 3,1 2,4 4,3
c
1 000 100 2 1,3 1 1,8 c
1 000 100 6 3,8 3 5,4
1 000 100 11 7 5,5 9,9
2 000 200 3 3,8 3 5,4
2 000 200 6 7,6 6 10,8
3,2
5 000 500 1 2,5 4,5
10 000 1 000 1 6,4 5 9
15 000 1 500 0,5 4,8 3,8 6,8
30 000 3 000 0,2 3,8 3 5,4
30 000 3 000 0,3 5,7 4,5 8,1
50 000 5 000 0,3 9,5 7,5 13,5 d
100 000 10 000 0,2 12,7 10 18
d
a
Preferred pulse shapes are printed in bold letters.
b
Recommendations given in RTCA DO 160E/F: 6 g “functional shock”, 3 per direction; 20 g “crash shock”, 1 per
direction.
c
Preferred severities for repetitive shocks.
d
These shocks may not be achievable within the stringent requirements of this standard.

6 Preconditioning
The relevant specification may call for preconditioning.

60068-2-27 © IEC:2008 – 15 –
7 Initial measurements and functional performance test
The specimen shall be submitted to visual, dimensional, functional and any other checks as
prescribed by the relevant specification.
8 Testing
The number of shocks prescribed by the relevant specification shall be applied successively in
each direction of three mutually perpendicular axes of the specimen. When testing a number of
identical specimens, they may be oriented so that the shocks are applied simultaneously along
these three axes (see Clause A.7).
Where the attitude of the specimen, when mounted or transported, is known, and since shocks
are generally of greatest significance in one direction of one axis, the relevant specification
shall state the specified number of shocks that shall be applied and in which axis, direction and
attitude. Otherwise, three axes and two directions shall be tested. For example, usually the
highest levels of shock acceleration are along the vertical axis. When the attitude during
transportation is known, the shocks should be applied in what will be the vertical axis in the
upward direction. Where the attitude is unknown, the specified number of shocks shall be
applied in each of the axes prescribed by the relevant specification (see Clause A.7).
The relevant specification shall state whether the specimen shall operate during testing and if
any functional monitoring is required.
9 Recovery
It is sometimes necessary to provide a period of time after testing and before final
measurements to allow the specimen to attain the same conditions, for example of
temperature, as existed for the initial measurements. The relevant specification shall then
prescribe the conditions for recovery.
10 Final measurements
The specimen shall be submitted to the visual, dimensional and functional checks and any
others as prescribed by the relevant specification.
The relevant specification shall provide the criteria upon which the acceptance or rejection of
the specimen shall be based.
11 Information to be given in the relevant specification
When this test is included in a relevant specification, the following details shall be given in so
far as they are applicable, paying particular attention to the items marked with an asterisk (*)
as this information is always required.
Clause
a) Pulse shape* 4.1.1 and A.3
b) Tolerances 4.1.1 and A.5
c) Velocity change 4.1.3 and A.6
d) Cross axis motion 4.1.4
e) Excitation axis, testing attitude and testing axes* 8
f) Method of mounting* 4.3
– 16 – 60068-2-27 © IEC:2008
g) Severity* 5 and A.4
h) Directions and number of shocks* 5 and 8
i) Preconditioning 6
j) Initial measurements 7
k) Functional performance test 7
l) Operating modes and functional monitoring 8
m) Recovery 9
n) Acceptance and rejection criteria* 10
o) Final measurements 10
12 Information to be given in the test report
As a minimum the test report shall show the following information:
1.  Customer   (name and address)
2.  Test laboratory  (name and address)
3.  Test report identification  (date of issue, unique number)
4.  Test dates
5.  Purpose of the test  (development test, qualification)
6.  Test standard, edition  (relevant test procedure)
7.  Test specimen description  (unique identity, drawing, photo, quantity,
comments on initial status of test specimen, etc.)
8.  Mounting of test specimen  (fixture identity, drawing, photo excitation axis)
9.  Excitation axis  (testing attitude and testing axes)
10.  Performance of test apparatus  (cross motion, etc.)
11.  Measuring system, sensor location  (description, drawing, photo)
12.  Uncertainties of measuring system (calibration data, last and next date)
13.  Initial, intermediate or final measurements
14.  Required severities  (from test specification)
15.  Test severities with documentation (measuring points)
16.  Test results  (comment on status of test specimen)
17.  Observations during testing and actions taken
18.  Summary of test
19.  Test manager  (name and signature)
20.  Distribution  (list of those receiving report)
NOTE A test log should be written, where the test is documented as, for example, a chronological list of test runs
with test parameters, observations during testing and actions taken, and data sheets on measurements made. The
test log can be attached to the test report.

60068-2-27 © IEC:2008 – 17 –
Annex A
(normative)
Selection and application of pulse shapes –
Guidance
A.1 Introduction
The test described in this standard provides a method to represent the effects on a specimen
when subjected to transportation or during operation. The test does not necessarily reproduce
the real environment.
The parameters given are standardized and suitable tolerances are chosen in order to obtain
similar results when a test is carried out at different locations by different people. The
standardization of values also enables components to be grouped into categories
corresponding to their ability to withstand certain severities given in this standard.
A.2 Applicability of test
Many specimens are liable to be subjected to shocks during use, storage and handling and
transportation. These shocks will be at widely varying levels and will also be of a complex
nature.
The shock test provides a convenient method for establishing the ability of a specimen to
withstand conditions of both non-repetitive and repetitive shocks. The test is performed on the
specimen when mounted to the fixture or table of the shock-testing machine. If the specimen is
installed or transported as loose cargo and subjected to repetitive shocks, then the test shall
be performed according to IEC 60068-2-55 (see Annex C).
The shock test is also suitable for structural integrity tests on component type specimens for
qualification and/or for quality control purposes. It is normal under these circumstances to
utilize high acceleration shocks with the main purpose of applying a known force to the internal
structure of a specimen, particularly those containing cavities, that is hollow spaces, (see
Clause 1).
To ensure that all test information is provided, the specification writer should refer to Clause 11
of this standard.
A.3 Pulse shapes (see Clause 1)
For test purposes, there are three ‘classical’ shock pulse shapes which are in general use and
any of these may be used (see also 4.1.1 and Table 1).
The half-sine pulse has application when reproducing the effects of a shock resulting from
impact with, or retardation by, a linear rate system, for example impact involving a resilient
structure.
The final-peak saw-tooth pulse has a more uniform response spectrum than the half-sine and
trapezoidal pulse shapes.
The trapezoidal pulse produces a higher response over a wider frequency spectrum than the
half-sine pulse. It should be applied when the purpose of the test is to reproduce the effects of
shock environments such as the “explosive bolt” phase of a space probe/satellite launch.

– 18 – 60068-2-27 © IEC:2008
NOTE The half-sine pulse shape is the most generally applicable. The trapezoidal pulse shape is not primarily
intended for component type specimens.
Information on the shock response spectra associated with these pulses is given in Annex B.
Where the shock response spectrum of the operational/transportation environment is known,
reference should be made to Figures A.1, A.2 and A.3 in order to select the shape of the pulse
most nearly conforming to it. Where the shock response spectrum of the
operational/transportation environment is not known, reference should be made to Tables A.1
and A.2 which list the test severities and pulse shapes applicable to specimens intended for
various classes of transportation and operational use.
For packaged items, the shocks encountered during handling and transportation are often of a
simple nature which makes it possible to use a half-sine pulse derived from the observed
velocity change.
60068-2-27 © IEC:2008 – 19 –
Figure A.1 – Shock response spectrum of a symmetrical half-sine pulse
Normalized
maximum response
Maximum response for A = 490 m/s
m/s
Acceleration
a
max
A
A
2,0 1 000
Exciting
pulse
1,8
1,6
1,4
0 D Time
1,2
1,0  500
0,8
0,6
0,4
0,2
1 10 100 1 000  Hz Frequency for D = 0,011s
Generalized frequency fD
0,02 0,05 0,1 0,2 0,5 1 2 5 10
I = initial
R = residual
IEC  308/08
– 20 – 60068-2-27 © IEC:2008
Figure A.2 – Shock response spectrum of a final-peak saw-tooth pulse
Normalized
maximum response
Maximum response for A = 490 m/s
a
m/s
max
Acceleration
A
2,0 1 000 A
Exciting
pulse
1,8
1,6
1,4 0
0 D Time
1,2
1,0
0,8
0,6
0,4
0,2
1 10 100 1 000  Hz Frequency for D = 0,011s
Generalized frequency fD
0,02 0,05 0,1 0,2 0,5 1 2 5 10
I = initial
R = residual
IEC  307/08
60068-2-27 © IEC:2008 – 21 –
Figure A.3 – Shock response spectrum of a symmetrical trapezoidal pulse
Normalized
maximum response
Maximum response for A = 490 m/s
Acceleration
m/s
a
max
A
A
Exciting
2,0 1 000
pulse
1,8
1,6
0 D Time
1,4
1,2
1,0
0,8
0,6
0,4
0,2
1 10 100 1 000  Hz Frequency for D = 0,011s
Generalized frequency fD
0,02 0,05 0,1 0,2 0,5 1 2 5 10
I = initial
R = residual
IEC  309/08
– 22 – 60068-2-27 © IEC:2008
A.4 Test severity
Whenever possible, the test severity and the shape of the shock pulse applied to the specimen
should be related to the environment to which the specimen will be subjected, during either
transportation, storage and handling, or operation, or to the design requirements if the object of
the test is to assess structural integrity.
It is often suitable to perform, on the same specimens, a test of non-repeated shocks (three
shocks in each axis and in each direction) using higher levels of stress to determine the ability
of the specimen to withstand the maximum stress that it may encounter during its normal life.
Also a test of repeated shocks at lower levels of stress may be conducted to determine the
ability of the specimen to withstand the repeatedly occurring shocks , maybe during operation,
during which the effect of material fatigue may be determined.
The transportation environment is frequently more severe than the operational environment
and in these circumstances the test severity chosen may need to be related to the former.
However, although the specimen may only need to survive the transportation environment, it
will normally be required to function during the operational environment, where appropriate.
Therefore, it may be necessary to carry out shock tests under both conditions, with
measurements of certain parameters after the “transportation environment” test and functional
checks during the “operational environment” test.
Consideration should be given to the possible need to allow an adequate safety margin
between the test severity and the conditions of the real environment.
When the real operational or transportation environment is unknown, the appropriate severity
should be selected from Table 1 which lists the test severities applicable for various classes of
transportation and operational use.
It is emphasized that the shock test is empirical and is basically a robustness test conducted in
order to give a measure of confidence. It is not intended to simulate precisely the real
environment.
In determining the test severity, the specification writer should take into account the
information given in relevant standards in the IEC 60721 series, namely IEC 60721-3-1 and
IEC 60721-3-5, remembering that these publications list values of shocks encountered in
practice whereas the intention of this standard is to standardize shock pulses for testing that
are likely to produce the same effects as real life shocks.

60068-2-27 © IEC:2008 – 23 –
Table A.1 – Examples of pulse shapes and test severities typically employed
for various applications
NOTE 1 This table lists severities which are not mandatory but are typical for the various applications. It should be
remembered that there will be instances where real severities differ from those shown in the table.
NOTE 2 Severities given in Table A.1 relate to test of non-repetitive shocks (three shocks in each axis and in each
direction). For test severities of repetitive shocks see Table A.2.
Severity
Peak Duration Pulse Component use Equipment use
acceleration shape
m/s g ms
n
150 15 11 Half-sine General test for robustness,
Final-peak handling and transport
saw-tooth
Land-based items permanently
Trapezoidal
installed or only transported by
road, rail or air in secured
shock-resistant packages
300 30 18 Half-sine Structural integrity of
Final-peak mountings
saw-tooth
Installed or transported in a
Trapezoidal
secured position on normal
road or rail vehicles or in
transport aircraft
500 50 11 Half-sine Items in secured packages Items installed or transported
Final-peak transported by wheeled in a secured position in full
saw-tooth vehicles (normal road and cross-country vehicles
a
Trapezoidal rail) subsonic or supersonic
Items carried loose in normal
transport aircraft, merchant
road or rai
...