SIST EN IEC 60068-3-3:2019

SLOVENSKI STANDARD
oSIST prEN IEC 60068-3-3:2018
01-oktober-2018
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Environmental testing - Part 3-3: Guidance - Seismic test methods for equipments
Essais d'environnement - Partie 3-3: Guide - Méthodes d'essais sismiques applicables
aux matériels
Ta slovenski standard je istoveten z: prEN IEC 60068-3-3:2018
ICS:
19.040 Preskušanje v zvezi z Environmental testing
okoljem
oSIST prEN IEC 60068-3-3:2018 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN IEC 60068-3-3:2018

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oSIST prEN IEC 60068-3-3:2018
104/806/CDV

COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60068-3-3 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2018-08-10 2018-11-02
SUPERSEDES DOCUMENTS:
104/787/CD,104/804/CC

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


Other TC/SCs are requested to indicate their interest, if
any, in this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY

SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.

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

TITLE:
Environmental testing - Part 3-3: Guidance - Seismic test methods for equipments

PROPOSED STABILITY DATE: 2024

NOTE FROM TC/SC OFFICERS:


Copyright © 2018 International Electrotechnical Commission, IEC. All rights reserved. It is permitted to
download this electronic file, to make a copy and to print out the content for the sole purpose of preparing National
Committee positions. You may not copy or "mirror" the file or printed version of the document, or any part of it, for
any other purpose without permission in writing from IEC.

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1 CONTENTS
2
3
4 Page
5 Clause
6 FOREWORD . 3
7 INTRODUCTION . 4
8 I - SECTION ONE – GENERAL . 5
9 1 Scope . 5
10 2 Normative references . 5
11 3 Terms and definitions . 6
12 4 General and qualification considerations . 11
13 5 Testing procedures . 12
14 6 Conditioning . 13
15 7 Test wave selection . 13
16 8 Test waves . 14
17 9 Testing conditions . 17
18 10 Single and multi-axis testing . 21
19 II - SECTION TWO – GENERAL SEISMIC CLASS . 23
20 11 Conditioning . 23
21 12 Calculated amplitude test method . 24
22 13 Testing parameters . 27
23 14 Definition of the Required Response Spectrum . 28
24 15 Testing procedures . 29
25 III - SECTION THREE – SPECIFIC SEISMIC CLASS . 31
26 16 Conditioning . 31
27 17 Test wave selection . 31
28 18 Test waves . 31
29 19 Testing conditions . 32
30 20 Single and multi-axis testing . 32
31 FIGURES . 33
32 Annex A Flow charts for test selection . 40
33
34

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35 INTERNATIONAL ELECTROTECHNICAL COMMISSION
36 –––––––––
37 ENVIRONMENTAL TESTING –
38
39 Part 3-3: Guidance – Seismic test methods for equipments
40
41 FOREWORD
42 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
43 all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
44 international co-operation on all questions concerning standardization in the electrical and electronic fields. To
45 this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
46 Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
47 Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
48 in the subject dealt with may participate in this preparatory work. International, governmental and non-
49 governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
50 with the International Organization for Standardization (ISO) in accordance with conditions determined by
51 agreement between the two organizations.
52 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
53 consensus of opinion on the relevant subjects since each technical committee has representation from all
54 interested IEC National Committees.
55 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
56 Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
57 Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
58 misinterpretation by any end user.
59 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
60 transparently to the maximum extent possible in their national and regional publications. Any divergence
61 between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
62 the latter.
63 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
64 assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
65 services carried out by independent certification bodies.
66 6) All users should ensure that they have the latest edition of this publication.
67 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
68 members of its technical committees and IEC National Committees for any personal injury, property damage or
69 other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
70 expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
71 Publications.
72 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
73 indispensable for the correct application of this publication.
74 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
75 patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
76 International Standard IEC 60068-3-3 has been prepared by IEC technical committee TC 104.
77 This second edition cancels and replaces the first edition published in 1991-02-28 This edition
78 constitutes a technical revision.
79 This edition includes the following significant technical changes with respect to the previous
80 edition:
81 - The main aim of this revision is to connect the testing level to the seismic activity level of
82 the zone where the equipment could be installed;
83 - A standard shape for the Required Response Spectrum is given also for the General
84 Seismic Class for which the seismic environment is either not known or is imprecisely
85 known;

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86 - With reference to the old document clauses from 11 to 15 were moved in section one by
87 renumbering them and by making some adjustments. This action is justified because the
88 contents of those clauses are very general and the requirements can be applied both to
89 the general seismic class and to the specific seismic class;
90 - The word “envelope” is changed into “dominance” and “to envelope” into “to dominate”
91 for getting a more precise meaning from the mathematical point of view.
92 The text of this International Standard is based on the following documents:
FDIS Report on voting
XX/XX/FDIS XX/XX/RVD
93
94 Full information on the voting for the approval of this International Standard can be found in
95 the report on voting indicated in the above table.
96 This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
97 The committee has decided that the contents of this document will remain unchanged until the
98 stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
99 the specific document. At this date, the document will be
100 • reconfirmed,
101 • withdrawn,
102 • replaced by a revised edition, or
103 • amended.
104
105 The National Committees are requested to note that for this document the stability date
106 is 2024XX.
107 THIS TEXT IS INCLUDED FOR THE INFORMATION OF THE NATIONAL COMMITTEES AND WILL BE
108 DELETED AT THE PUBLICATION STAGE.
109
110
111 INTRODUCTION
112 Guidance is included in each of the two test methods referred to in this standard but it is
113 specific to the test method. The guidance in this standard is directed towards choosing the
114 appropriate test method and applying it to seismic testing.
115 This standard is to be used in conjunction with IEC 60068-1.

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116 ENVIRONMENTAL TESTING –
117
118 Part 3-3: Guidance – Seismic test methods for equipments
119
120
121 I - SECTION ONE – GENERAL
122
123 1 Scope
124 This document applies primarily to electro-technical equipments but its application can be
125 extended to other equipments and to components.
126 Also if some sort of analysis is always performed when making a seismic qualification, e.g. for
127 the choice of the representative sample to be tested or for the extension of the seismic
128 qualification from the tested specimen to similar specimens, the verification of the
129 performance of an equipment by analysis or by a combination of testing and analysis may be
130 acceptable but is outside the scope of this guide, which is restricted to verification based
131 entirely upon data from dynamic testing.
132 This guide deals solely with the seismic testing of a full-size equipment which can be tested
133 on a vibration table. The seismic testing of an equipment is intended to demonstrate its ability
134 to perform its required function during and/or after the time it is subjected to the stresses and
135 displacements resulting from an earthquake.
136 The object of this guide is to present a range of methods of testing which, when prescribed by
137 the relevant specification, can be applied to demonstrate the performance of equipments for
138 which seismic testing is required with the main aim of achieving qualification.
139 NOTE Qualification by so-called “fragility-testing” is not considered to be within the scope of this guide which has
140 been prepared to give generally applicable guidance on seismic testing and specifically on the use of IEC 60068-2
141 test methods.
142 The choice of the method of testing can be made according to the criteria described in this
143 guide. The methods themselves are closely based on published IEC test methods.
144 This guide is intended for use by manufacturers to substantiate, or by users to evaluate and
145 verify, the performance of an equipment.
146 2 Normative references
147 The following documents are referred to in the text in such a way that some or all of their
148 content constitutes requirements of this document. For dated references, only the edition
149 cited applies. For undated references, the latest edition of the referenced document (including
150 any amendments) applies.
151 IEC 60068-1 Environmental testing – Part 1: General and guidance
152 IEC 60068-2-6 Test Fc and guidance: Vibration (sinusoidal)
153 IEC 60068-2-47 Mounting of components, equipment and other articles for dynamic tests
154 including shock (Ea), bump (Eb), vibration (Fc and Fd) and steady-state acceleration (Ga) and
155 guidance

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156 IEC 60068-2-57 Environmental testing – Part 2: Tests – Test Ff: Vibration – Time-history
157 and sine-beat method.
158 IEC 60068-2-64 Environmental testing – Part 2-64: Tests – Test Fh: Vibration, broadband
159 random (digital control) and guidance
160 IEC 60068-2-81 2003 Environmental testing – Part 2-81: Tests – Test Ei: Shock – Shock
161 response spectrum synthesis
162 IEC 60721-2-6: 1990 Classification of environmental conditions. Part 2: Environmental
163 conditions appearing in nature. Earthquake vibration and shock
164 IEC TS 62271-210:2013 High-voltage switchgear and controlgear – Part 210: Seismic
165 qualification for metal enclosed and solid-insulation enclosed switchgear and controlgear
166 assemblies for rated voltages above 1 kV and up to and including 52 kV
167 ISO 2041 – Vibration and shock – Vocabulary
168 3 Terms and definitions
169 The terms used in this standard are generally defined in ISO 2041 or in IEC 60068-1, IEC
170 60068-2-6 and IEC 60068-2-57. Where, for the convenience of the reader, a definition from
171 one of these sources is included here, the derivation is indicated and departures from the
172 definitions in those sources are also indicated.
173 The additional terms and definitions that follow are also applicable for the purpose of this
174 standard.
175 3.1
176 assembly
177 two or more devices sharing a common mounting or supporting structure
178 3.2
179 bandpass at –3 dB
180 frequency intervals defined by the points possessing an ordinate larger than or equal to 2 /2
181 times the maximum value of the plot
182 Note 1 to entry: See figure 2.
183 3.3
184 basic response spectrum
185 unmodified response spectrum defined by the characteristics of the building, its floor level,
186 damping ratio, etc. and obtained from a specific ground motion
187 Note 1 to entry: See figure 2.
188
189 Note 2 to entry The basic response spectrum is generally of the narrow band type at floor level. The basic
190 response spectrum is calculated by the architect engineer of the plant and it is generally not known by the
191 equipment manufacturer and by the test engineer.
192 3.4
193 broadband response spectrum
194 response spectrum that describes the motion indicating that a number of interacting
195 frequencies exist which must be treated as a whole
196 Note 1 to entry: See figure 3c.

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197 Note 2 to entry The bandwidth is normally greater than one octave.
198 3.5
199 critical frequency
200 frequencies at which:
201 – malfunctioning and/or deterioration of performance of the specimen which are dependent
202 on vibration are exhibited, and/or
203 – mechanical resonances and/or other response effects occur, for example chatter
204 [SOURCE: IEC 60068-2-6, 3.9, modified – The text was editorially corrected]
205 3.6
206 crossover frequency
207 frequency at which the characteristic of a vibration changes from one relationship to another
208 Note 1 to entry For example, a crossover frequency may be that frequency at which the control of the test
209 vibration amplitude changes from a constant displacement value versus frequency to a constant acceleration value
210 versus frequency.
211 [SOURCE: ISO 2041, 2.118, modified – Example omitted and note added]
212 3.7
213 damping
214 generic term ascribed to the numerous energy dissipation mechanisms in a system. In
215 practice, damping depends on many parameters, such as the structural system, mode of
216 vibration, strain, applied forces, velocity, materials, joint slippage, etc.
217 Note 1 to entry This definition is not identical with ISO 2041 definition.
218 3.7.1
219 critical damping
220 minimum viscous damping that will allow a displaced system to return to its initial position
221 without oscillation
222 3.7.2
223 damping ratio
224 ratio of actual damping to critical damping in a system with viscous damping
225 3.8
226 direction factor
227 factor taking account of the difference in magnitude at ground level that normally exists
228 between the horizontal and vertical accelerations resulting from an earthquake
229 3.9
230 floor acceleration
231 acceleration of a particular building floor (or an equipment mounting) resulting from the
232 ground motion of a given earthquake
233 Note 1 to entry In practice the floor acceleration may be resolved into its horizontal and vertical components.
234 3.10
235 geometric factor
236 factor required in single axis testing to take into account the interaction along the different
237 axes of the equipment of simultaneous multi-directional input vibrations
238 3.11
239 “g ”
n
240 standard acceleration due to the earth's gravity, which itself varies with altitude and
241 geographical latitude

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242 Note 1 to entry For the purposes of this standard, the value of g is rounded up to the nearest whole number, that
n
2
243 is 10 m/s .
244 3.12
245 ground acceleration
246 acceleration of the ground resulting from the motion of a given earthquake
247 Note 1 to entry In practice the ground acceleration may be resolved into its horizontal and vertical components.
248 3.13
249 lateral frequencies
250 two frequencies determined according to the –3 dB response around the overall resonance
251 frequency
252 Note 1 to entry: See figure2.
253 3.14
254 malfunction
255 loss of capability of the equipment to initiate or sustain a required function, or the initiation of
256 undesired spurious action which may result in adverse consequences for safety
257 Note 1 to entry Malfunction will be defined by the relevant specification.
258 3.15
259 narrowband response spectrum
260 response spectrum in which single frequency excitation predominates
261 Note 1 to entry: See figure 3a.
262 Note 2 to entry The bandwidth is normally 1/3 octave or less.
263 Note 3 to entry When several widely spaced well-defined frequencies exist, if justified, each of their responses
264 may be treated separately as a narrow-band response spectrum (see figure 3b).
265 3.16
266 damped natural frequency
267 frequency of free vibration of a damped linear system depending only on its own physical
268 characteristics (mass, stiffness, and damping)
269 3.17
270 overall resonance
271 resonance frequency at which a complete structure amplifies the exciting motion
272 Note 1 to entry Within the frequency range between 1 Hz and 35 Hz, overall resonance generally corresponds to
273 the first mode of vibration. It is important to take into account the overall resonance frequencies when they are
274 enclosed in the strong part of the required response spectrum (see 3.27).
275 3.18
276 pause
277 interval between consecutive test waves (for example sine beats)
278 Note 1 to entry A pause should be such that it results in no significant superposition of the response motions of
279 an equipment.
280 3.19
281 preferred testing axes
282 three orthogonal axes which correspond to the most vulnerable axes of the equipment
283 3.20
284 required response spectrum
285 response spectrum specified by the user

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286 Note 1 to entry: See figure1, 2 and 3.
287 3.21
288 resonance frequency
289 frequency at which, in forced oscillation, a change in the frequency of excitation causes a
290 decrease in the response of the system.
291 Note 1 to entry The value of resonance frequency depends upon the measured variable. For a damped linear
292 system, the values of resonance frequency for displacement, velocity and acceleration (respectively dynamic
293 compliance, mobility and accelerance; see ISO 2041) are in increasing order of frequency. The differences
294 between these resonance frequency values are small for the usual damping ratios.
295 Note 2 to entry In seismic testing, it is often assumed that a resonance frequency is significant when the
296 transmissibility of the response is greater than 2.
297 Note 3 to entry This definition is not identical with ISO 2041 definition.
298 3.22
299 response spectrum
300 plot of the maximum response to a defined input motion of a family of single-degree-of-
301 freedom bodies at a specified damping ratio
302 Note 1 to entry: See figure1, 2 and 3.
303 Note 2 to entry This definition is not identical with ISO 2041 definition.
304 3.23
305 S1-earthquake
306 an earthquake which would be expected to occur during the operating life of the equipment
307 and for which safety related equipments are to be designed to continue to operate without
308 malfunction
309 Note 1 to entry An S1-earthquake corresponds in nuclear applications to the operating base earthquake (OBE).
310 3.24
311 S2-earthquake
312 an earthquake which produces the maximum vibratory ground motion for which certain
313 structures, systems and components are designed to remain functional. These structures,
314 systems and components are those essential to assure proper function, integrity and safety of
315 the total system
316 Note 1 to entry An S2-earthquake corresponds in nuclear applications to the safe shutdown earthquake (SSE).
317 3.25
318 sine beat
319 continuous sinusoidal wave of one frequency which is modulated by a sinusoidal wave of a
320 lower frequency. The duration of one sine beat is half the period of the modulating frequency
321 Note 1 to entry: See figure 5.
322 Note 2 to entry In this standard, the sine beat is considered as a single frequency wave.
323 3.26
324 strong part of time-history
325 part of time-history from the time when the plot first reaches 25 % of the maximum value to
326 the time when it falls for the last time to the 25 % level.
327 Note 1 to entry: See figure 5.

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328 3.27
329 strong part of the response spectrum
330 part of the spectrum for which the response acceleration is higher than for the –3 dB
331 bandpass of the required response spectrum.
332 Note 1 to entry: See figure 2.
333 Note 2 to entry Generally, the strong part of the response spectrum is located in the first third of the frequency
334 band.
335 3.28
336 superelevation factor
337 factor accounting for the change in the acceleration with respect to the earth due to the
338 transmissibility of buildings and structures
339 3.29
340 synthesized time-history
341 artificially generated time-history such that its response spectrum dominates the required
342 response spectrum
343 3.30
344 test level
345 largest peak value within a test wave
346 Note 1 to entry In seismic testing, acceleration is the parameter normally used.
347 3.31
348 test frequency
349 frequency at which the specimen is to be excited during a test
350 Note 1 to entry: A test frequency is one of two types as defined in 3.31.1 and 3.31.2.
351 3.31.1
352 predetermined test frequency
353 frequency prescribed by the relevant specification
354 3.31.2
355 investigated test frequency
356 frequency obtained by a vibration response investigation
357 3.32
358 test response spectrum
359 response spectrum derived from the real motion of the vibration table either analytically or by
360 using spectrum analysis equipment
361 Note 1 to entry: See figures 1, 2c and 2d.
362 3.33
363 time-history
364 recording, as a function of time, of acceleration or velocity or displacement
365 Note 1 to entry This definition is not identical with ISO 2041 definition.
366
367 3.34
368 zero period acceleration
369 ZPA
370 high-frequency asymptotic value of acceleration of a response spectrum
371 Note 1 to entry: For an example see figure 2.

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372 Note 2 to entry The zero period acceleration is of practical significance as it represents the largest peak value of
373 acceleration, for example in a time-history. This should not be confused with the peak value of acceleration in the
374 response spectrum.
375 4 General and qualification considerations
376 4.1 General and specific seismic class
377 Two seismic classes have been established: a general seismic class and a specific seismic
378 class. Neither of these classes can be considered to be more demanding than the other. The
379 difference between the two classes lies in the availability of and/or the accuracy in defining
380 the characteristics of the seismic environment. When high reliability safety equipment for a
381 specified environment is required, such as safety related equipment in nuclear power plants,
382 the use of precise data is necessary and, therefore, the specific seismic class is applicable
383 and not the general seismic class. Annex A contains a flow chart for the selection of the test
384 class (general seismic class or specific seismic class) and three flow charts (A.1 to A.3)
385 covering the possibilities discussed in this guide. To obtain the maximum advantage from this
386 guide it is strongly recommended that the flow charts be studied very thoroughly.
387 Section Two describes the recommended seismic testing methods for equipment covered by
388 the general seismic class for which the seismic environment is either not known or is
389 imprecisely known.
390 This class covers equipments for which the relevant seismic motion does not result from a
391 specific study taking into account the characteristics of the geographic location and of the
392 supporting structure or building.
393 In this class, the seismic motion is generally characterized by one datum which is a peak
394 acceleration at the ground level. This acceleration is derived from the seismic data relative to
395 the area of interest.
396 When an equipment is not mounted at ground level, the transmissibility of the building and/or
397 the supporting structure should be taken into account.
398 Section Three describes the recommended seismic testi
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