Overhead lines - Requirements and tests for Aeolian vibration dampers

IEC 61897:2020 is available as IEC 61897:2020 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 61897:2020 applies to aeolian vibration dampers intended for single conductors or earth wires or conductor bundles where dampers are directly attached to each subconductor. The purchaser may adopt part(s) of this document when specifying requirements for cables different from those mentioned above (e.g. optical ground wires (OPGW), all dielectric self-supporting optical cables (ADSS)). In some cases, test procedures and test values are left to agreement between the purchaser and the supplier and are stated in the procurement contract. Annex A lists the minimum technical details to be agreed between purchaser and supplier. Throughout this document, the word “conductor” is used when the test applies to dampers for conductors or earth wires. This second edition cancels and replaces the first edition published in 1998. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) Consider, in addition to Stockbridge type aeolian vibration dampers, also spiral aeolian vibration dampers and elastomeric aeolian vibration dampers. b) Consider the application of dampers on high temperature conductors, specifying additional high temperature tests in clamp slip tests. c) Simplify the procedure of the damper effectiveness evaluation. d) Introduce test at low temperature on fastener components such as break away bolts and conical spring washers. e) Include figures showing the test arrangements for the main mechanical tests. Key words: Overhead Lines, Aeolian Vibration Dampers

Freileitungen – Anforderungen und Prüfungen für Schwingungsdämpfer

Lignes aériennes - Exigences et essais applicables aux amortisseurs de vibrations éoliennes

IEC 61897:2020 est disponible sous forme de IEC 61897:2020 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente. IEC 61897:2020 s'applique aux amortisseurs de vibrations éoliennes pour conducteurs uniques ou câbles de garde, ou aux faisceaux de conducteurs lorsque les amortisseurs sont directement reliés à chaque sous-conducteur. L'acheteur peut adopter un ou plusieurs fragments du présent document lors de la spécification d'exigences concernant des câbles différents de ceux mentionnés ci-dessus, par exemple les câbles de garde optiques (OPGW, Optical Ground Wire) ou les câbles optiques autoporteurs entièrement diélectriques (ADSS, All Dielectric Self-Supporting). Dans certains cas, les procédures et valeurs d'essai sont convenues entre l'acheteur et le fournisseur et sont indiquées dans le contrat d'approvisionnement. L'annexe A contient les informations techniques minimales à convenir entre l'acheteur et le fournisseur. Dans le cadre du présent document, le mot "conducteur" est utilisé lorsque l'essai s'applique aux amortisseurs pour conducteurs ou câbles de garde.

Nadzemni vodi - Zahteve in preskusi za dušilnike vetrnih vibracij (IEC 61897:2020)

General Information

Status
Published
Publication Date
16-Apr-2020
Current Stage
6060 - Document made available
Due Date
17-Apr-2020
Completion Date
17-Apr-2020

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SLOVENSKI STANDARD
SIST EN IEC 61897:2021
01-januar-2021
Nadomešča:
SIST EN 61897:1999

Nadzemni vodi - Zahteve in preskusi za dušilnike vetrnih vibracij (IEC 61897:2020)

Overhead lines - Requirements and tests for Aeolian vibration dampers (IEC
61897:2020)
Freileitungen - Anforderungen und Prüfungen für Schwingungsdämpfer (IEC
61897:2020)

Lignes aériennes - Exigences et essais applicables aux amortisseurs de vibrations

éoliennes (IEC 61897:2020)
Ta slovenski standard je istoveten z: EN IEC 61897:2020
ICS:
29.240.20 Daljnovodi Power transmission and
distribution lines
SIST EN IEC 61897:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN IEC 61897:2021
---------------------- Page: 2 ----------------------
SIST EN IEC 61897:2021
EUROPEAN STANDARD EN IEC 61897
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2020
ICS 29.240.20 Supersedes EN 61897:1998 and all of its amendments
and corrigenda (if any)
English Version
Overhead lines - Requirements and tests for Aeolian vibration
dampers
(IEC 61897:2020)

Lignes aériennes - Exigences et essais applicables aux Freileitungen - Anforderungen und Prüfungen für

amortisseurs de vibrations éoliennes Schwingungsdämpfer
(IEC 61897:2020) (IEC 61897:2020)

This European Standard was approved by CENELEC on 2020-04-07. CENELEC members are bound to comply with the CEN/CENELEC

Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC

Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation

under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the

same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,

Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the

Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2020 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN IEC 61897:2020 E
---------------------- Page: 3 ----------------------
SIST EN IEC 61897:2021
EN IEC 61897:2020 (E)
European foreword

The text of document 11/266/FDIS, future edition 2 of IEC 61897, prepared by IEC/TC 11 "Overhead

lines" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
EN IEC 61897:2020.
The following dates are fixed:

• latest date by which the document has to be implemented at national (dop) 2021-01-07

level by publication of an identical national standard or by endorsement

• latest date by which the national standards conflicting with the (dow) 2023-04-07

document have to be withdrawn

This document supersedes EN 61897:1998 and all of its amendments and corrigenda (if any).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Endorsement notice

The text of the International Standard IEC 61897:2020 was approved by CENELEC as a European

Standard without any modification.
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SIST EN IEC 61897:2021
EN IEC 61897:2020 (E)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the relevant

EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:

www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60050-466 1990 International Electrotechnical Vocabulary. - -
Chapter 466: Overhead lines
IEC 60888 1987 Zinc-coated steel wires for stranded - -
conductors
IEC 61284 1997 Overhead lines - Requirements and tests EN 61284 1997
for fittings
IEC 61854 - Overhead lines - Requirements and tests - -
for spacers
IEC 62567 2013 Overhead lines - Methods for testing self- EN 62567 2013
damping characteristics of conductors
ISO 1461 2009 Hot dip galvanized coatings on fabricated EN ISO 1461 2009
iron and steel articles - Specifications and
test methods
ISO 2859-1 1999 Sampling procedures for inspection by - -
attributes - Part 1: Sampling schemes
indexed by acceptance quality limit (AQL)
for lot-by-lot inspection
+ A1 2011 - -
ISO 2859-2 1985 Sampling procedures for inspection by - -
attributes - Part 2: Sampling plans
indexed by limiting quality (LQ) for
isolated lot inspection
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SIST EN IEC 61897:2021
EN IEC 61897:2020 (E)
ISO 3951-1 2013 Sampling procedures for inspection by - -
variables - Part 1: Specification for single
sampling plans indexed by acceptance
quality limit (AQL) for lot-by-lot inspection
for a single quality characteristic and a
single AQL
ISO 3951-2 2013 Sampling procedures for inspection by - -
variables - Part 2: General specification
for single sampling plans indexed by
acceptance quality limit (AQL) for lot-by-
lot inspection of independent quality
characteristics
ISO 9001 2015 Quality management systems - EN ISO 9001 2015
Requirements
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SIST EN IEC 61897:2021
IEC 61897
Edition 2.0 2020-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Overhead lines – Requirements and tests for aeolian vibration dampers
Lignes aériennes – Exigences et essais applicables aux amortisseurs
de vibrations éoliennes
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.240.20 ISBN 978-2-8322-7800-0

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 7 ----------------------
SIST EN IEC 61897:2021
– 2 – IEC 61897:2020 © IEC 2020
CONTENTS

FOREWORD ........................................................................................................................... 4

1 Scope .............................................................................................................................. 6

2 Normative references ...................................................................................................... 6

3 Terms and definitions ...................................................................................................... 7

4 General requirements ...................................................................................................... 7

4.1 Design .................................................................................................................... 7

4.2 Materials ................................................................................................................. 8

4.3 Mass, dimensions and tolerances ........................................................................... 8

4.4 Protection against corrosion .................................................................................... 8

4.5 Manufacturing appearance and finish ...................................................................... 8

4.6 Marking ................................................................................................................... 8

4.7 Installation instructions ........................................................................................... 8

5 Quality assurance ............................................................................................................ 8

6 Classification of tests....................................................................................................... 9

6.1 Type tests ............................................................................................................... 9

6.1.1 General ........................................................................................................... 9

6.1.2 Application ....................................................................................................... 9

6.2 Sample tests ........................................................................................................... 9

6.2.1 General ........................................................................................................... 9

6.2.2 Application ....................................................................................................... 9

6.2.3 Sampling, acceptance criteria .......................................................................... 9

6.3 Routine tests......................................................................................................... 10

6.3.1 General ......................................................................................................... 10

6.3.2 Application and acceptance criteria ............................................................... 10

6.4 Table of tests to be applied ................................................................................... 10

7 Test methods ................................................................................................................. 11

7.1 Visual examination ................................................................................................ 11

7.2 Verification of dimensions, materials and mass ..................................................... 11

7.3 Corrosion protection tests ..................................................................................... 11

7.3.1 Hot dip galvanized components (other than messenger cable wires) .............. 11

7.3.2 Ferrous components protected from corrosion by methods other than

hot dip galvanizing ......................................................................................... 12

7.3.3 Hot dip galvanized messenger cable wires .................................................... 12

7.4 Non-destructive tests ............................................................................................ 12

7.5 Clamp slip test ...................................................................................................... 12

7.6 Breakaway bolt test .............................................................................................. 13

7.7 Clamp bolt tightening test ..................................................................................... 14

7.8 Attachment of weights to messenger cable test ..................................................... 14

7.9 Attachment of clamp to messenger cable test ....................................................... 15

7.10 Corona and radio interference voltage (RIV) tests ................................................. 15

7.11 Damper performance tests .................................................................................... 15

7.11.1 Performance test variants .............................................................................. 15

7.11.2 Damper characteristic test ............................................................................. 16

7.11.3 Damper effectiveness evaluation ................................................................... 18

7.12 Damper fatigue test .............................................................................................. 21

7.12.1 Test methods ................................................................................................. 21

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SIST EN IEC 61897:2021
IEC 61897:2020 © IEC 2020 – 3 –

7.12.2 Swept frequency method ............................................................................... 21

7.12.3 Resonant frequency method .......................................................................... 21

7.12.4 Acceptance criteria ........................................................................................ 22

7.12.5 Fatigue test method – for spiral aeolian vibration dampers (SVD) .................. 22

Annex A (normative) Minimum technical details to be agreed between purchaser and

supplier ................................................................................................................................. 23

Annex B (informative) Examples of graphs relevant to damper characteristic test ................ 24

Annex C (normative) Wind power input curve ....................................................................... 25

Annex D (informative) Description of HT conductors as given in

CIGRE TB 695‑2017 [6] ........................................................................................................ 27

Bibliography .......................................................................................................................... 28

Figure 1 – Test arrangement for longitudinal slip tests .......................................................... 13

Figure 2 – Test arrangement for attachment of weights to messenger cable test ................... 15

Figure 3 – Test arrangement for attachment of clamp to messenger cable test ..................... 15

Figure 4 – Test arrangement for damper characteristic test ................................................... 18

Figure 5 – Example of test rig for laboratory test of damper effectiveness ............................. 18

Figure B.1 – Examples of graphs relevant to damper characteristic test (damper with

two resonant frequencies) ..................................................................................................... 24

Figure C.1 – Wind power input curve .................................................................................... 25

Table 1 – Tests on dampers .................................................................................................. 10

Table 2 – Load criteria (for standard and high temperature conductors) ................................ 13

Table 3 – Acceptance criteria ................................................................................................ 17

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SIST EN IEC 61897:2021
– 4 – IEC 61897:2020 © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_____________
OVERHEAD LINES –
REQUIREMENTS AND TESTS FOR AEOLIAN VIBRATION DAMPERS
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 61897 has been prepared by Technical Committee 11: Overhead

lines.

This second edition cancels and replaces the first edition published in 1998. This edition

constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:

a) Consider, in addition to Stockbridge type aeolian vibration dampers, also spiral aeolian

vibration dampers and elastomeric aeolian vibration dampers.

b) Consider the application of dampers on high temperature conductors, specifying additional

high temperature tests in clamp slip tests.
c) Simplify the procedure of the damper effectiveness evaluation.

d) Introduce test at low temperature on fastener components such as break away bolts and

conical spring washers.
e) Include figures showing the test arrangements for the main mechanical tests.
---------------------- Page: 10 ----------------------
SIST EN IEC 61897:2021
IEC 61897:2020 © IEC 2020 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
11/266/FDIS 11/273/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 document has been drafted in accordance with the ISO/IEC Directives, Part 2.

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
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SIST EN IEC 61897:2021
– 6 – IEC 61897:2020 © IEC 2020
OVERHEAD LINES –
REQUIREMENTS AND TESTS FOR AEOLIAN VIBRATION DAMPERS
1 Scope

This document applies to aeolian vibration dampers intended for single conductors or earth

wires or conductor bundles where dampers are directly attached to each subconductor.

The purchaser may adopt part(s) of this document when specifying requirements for cables

different from those mentioned above (e.g. optical ground wires (OPGW), all dielectric self-

supporting optical cables (ADSS)).

In some cases, test procedures and test values are left to agreement between the purchaser

and the supplier and are stated in the procurement contract.

Annex A lists the minimum technical details to be agreed between purchaser and supplier.

Throughout this document, the word “conductor” is used when the test applies to dampers for

conductors or earth wires.
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 60050(466):1990, International Electrotechnical Vocabulary (IEV) – Chapter 466:

Overhead lines
IEC 60888:1987, Zinc-coated steel wires for stranded conductors
IEC 61284:1997, Overhead lines – Requirements and tests for fittings
IEC 61854, Overhead lines – Requirements and tests for spacers

IEC 62567:2013, Overhead lines – Methods for testing self-damping characteristics of

conductors

ISO 1461:2009, Hot dip galvanized coatings on fabricated iron and steel articles –

Specifications and test methods

ISO 2859-1:1999/AMD1:2011, Sampling procedures for inspection by attributes – Part 1:

Sampling schemes indexed by acceptable quality limit (AQL) for lot-by-lot inspection

ISO 2859-2:1985, Sampling procedures for inspection by attributes – Part 2: Sampling plans

indexed by limiting quality level (LQ) for isolated lot inspection

ISO 3951-1:2013, Sampling procedures for inspection by variables – Part 1: Specification for

single sampling plans indexed by acceptance quality limit (AQL) for lot-by-lot inspection for a

single quality characteristic and a single AQL
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SIST EN IEC 61897:2021
IEC 61897:2020 © IEC 2020 – 7 –

ISO 3951-2:2013, Sampling procedures for inspection by variables – Part 2: General

specification for single sampling plans indexed by acceptance quality limit (AQL) for lot-by-lot

inspection of independent quality characteristics
ISO 9001:2015, Quality management systems – Requirements
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 60050-466 apply, as

well as the following.

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
stockbridge-type aeolian vibration damper

device comprising a steel cable with a weight at each end and one bolted clamp or a helical rod

attachment, attachable to a conductor, for the purpose of damping aeolian vibration

3.2
spiral aeolian vibration damper
SVD

device made of helical plastic which wraps around the conductor for purposes of damping

aeolian vibration (these are commonly used on earth wires, OPGW and ADSS cables)
3.3
elastomeric aeolian vibration damper

device comprising suspended weights connected to elastomeric articulations and one bolted

clamp or a helical rod attachment, attachable to a conductor for the purpose of damping

aeolian vibration
3.4
high temperature conductors
HTC
conductors which are designed to have a maximum continuous operating temperature
over 95 °C
3.5
maximum continuous operating temperature

conductor temperature specified by the manufacturer and measured at the outer wire layers

4 General requirements
4.1 Design
The damper shall be designed so as to
– damp aeolian vibration;

– withstand mechanical loads imposed during installation, maintenance and specified

service conditions;
– avoid damage to the conductor under specified service conditions;
– be capable of being removed and re-installed without damage to the conductor;
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SIST EN IEC 61897:2021
– 8 – IEC 61897:2020 © IEC 2020

– be free from unacceptable levels of corona and radio interference under all service

conditions, when installed on phase conductors;

– be suitable for safe and easy installation. The clamp design shall retain all parts when

opened for attachment to conductor. Furthermore, the clamp design shall be such that the

damper, during installation, can be suspended on the conductor before tightening the

clamp;
– ensure that individual components will not become loose in service;
– maintain its function over the entire service temperature range;
– avoid audible noise;
– prevent water collection.

Other desirable characteristics which are not essential to the basic functions of the damper

but which may be advantageous include:
– verification of proper installation from the ground;
– easy installation and removal from energized lines.

In the case of vibration dampers for conductors or earth wires containing integral fibre optic

elements (or an externally applied optical cable wrapped around the earth wire) the possible

effects of the damper on these fibre optic elements should be accounted for.
4.2 Materials
The materials shall conform to the requirements of IEC 61284.
4.3 Mass, dimensions and tolerances

Damper mass and significant dimensions, including appropriate tolerances, shall be shown on

contract drawings.
4.4 Protection against corrosion

In addition to the applicable requirements of IEC 61284, the messenger cable (including cut

ends when exposed) shall be protected against corrosion, e.g. in accordance with IEC 60888

for hot dip galvanized steel wire.
4.5 Manufacturing appearance and finish

The dampers shall be free of defects and irregularities; they shall have all outside surfaces

smooth and all edges and corners well-rounded.
4.6 Marking

The fitting marking requirements of IEC 61284 shall be applied to all clamp assemblies

including those using breakaway bolts. On spiral dampers, the markings should be on the

plastic rod.
4.7 Installation instructions

The supplier shall provide a clear and complete description of the recommended installation

procedure including in-span positions.
5 Quality assurance

A quality assurance programme taking into account the requirements of this document can be

used by agreement between the purchaser and the supplier to verify the quality of the

vibration dampers during the manufacturing process.
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SIST EN IEC 61897:2021
IEC 61897:2020 © IEC 2020 – 9 –

Detailed information on the use of quality assurance is given in a system as per ISO 9001 or

similar.

It is recommended that test equipment used to verify compliance to this document is routinely

maintained and calibrated in accordance with a relevant quality standard.
6 Classification of tests
6.1 Type tests
6.1.1 General

Type tests are intended to establish design characteristics. They are normally made once and

repeated only when the design or the material of the damper components is changed. The

results of type tests are recorded as evidence of compliance with design requirements.

6.1.2 Application
Dampers shall be subjected to type tests as per Table 1.

Unless otherwise specified, each type test shall be performed on three test samples which are

identical in all essential respects with dampers to be supplied under contract to the purchaser.

All units shall pass the tests.

The dampers used for tests during which no damage occurs to the units or their components

may be used in subsequent tests.
6.2 Sample tests
6.2.1 General

Sample tests are required to verify that the dampers meet the performance specifications of

the type test samples. In addition, they are intended to verify the quality of material and

workmanship.
6.2.2 Application
Dampers shall be subjected to sample tests as per Table 1.

The samples to be tested shall be selected at random from the lot offered for acceptance. The

purchaser has the right to make the selection.

The dampers used for tests during which no damage occurs to the units or their components

may be used in subsequent tests.
6.2.3 Sampling, acceptance criteria

The sampling plan procedures according to ISO 2859-1 and ISO 2859-2 (inspection by

attributes) and ISO 3951 (inspection by variables) and the detailed procedures (inspection

level, AQL, single, double or multiple sampling, etc.) shall be agreed between the purchaser

and the supplier for each different attribute or variable.

NOTE Sampling inspection by variables is an acceptance sampling procedure to be used in place of inspection by

attri
...

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