EN ISO 21181:2013

SLOVENSKI STANDARD
01-junij-2013
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SIST EN ISO 21181:2007
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Light conveyor belts - Determination of the relaxed elastic modulus (ISO 21181:2013)
Leichte Fördergurte - Bestimmung des relaxierten Elastizitätsmoduls (ISO 21181:2013)
Courroies transporteuses légères - Détermination du module d'élasticité relaxé (ISO
21181:2013)
Ta slovenski standard je istoveten z: EN ISO 21181:2013
ICS:
53.040.10 Transporterji Conveyors
53.040.20 Deli za transporterje Components for conveyors
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 21181
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2013
ICS 53.040.20 Supersedes EN ISO 21181:2006
English Version
Light conveyor belts - Determination of the relaxed elastic
modulus (ISO 21181:2013)
Courroies transporteuses légères - Détermination du
module d'élasticité relaxé (ISO 21181:2013)
This European Standard was approved by CEN on 12 February 2013.

CEN 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 CEN 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 CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2013 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21181:2013: E
worldwide for CEN national Members.

Contents Page
Foreword . 3

Foreword
This document (EN ISO 21181:2013) has been prepared by Technical Committee ISO/TC 41 "Pulleys and
belts (including veebelts)" in collaboration with Technical Committee CEN/TC 188 “Conveyor belts” the
secretariat of which is held by SNV.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by August 2013, and conflicting national standards shall be withdrawn at
the latest by August 2013.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 21181:2006.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 21181:2013 has been approved by CEN as EN ISO 21181:2013 without any modification.

INTERNATIONAL ISO
STANDARD 21181
Second edition
2013-02-15
Light conveyor belts — Determination
of the relaxed elastic modulus
Courroies transporteuses légères — Détermination du module
d’élasticité relaxé
Reference number
ISO 21181:2013(E)
©
ISO 2013
ISO 21181:2013(E)
© ISO 2013
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
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Published in Switzerland
ii © ISO 2013 – All rights reserved

ISO 21181:2013(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Principle . 2
6 Apparatus . 2
7 Test pieces . 2
7.1 Shape, dimensions, number and selection . 2
7.2 Conditioning . 3
8 Procedure. 3
9 Calculation and expression of results . 4
10 Test report . 6
Bibliography . 7
ISO 21181:2013(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International
Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies
casting a vote.
ISO 21181 was prepared by Technical Committee ISO/TC 41, Pulleys and belts (including veebelts),
Subcommittee SC 3, Conveyor belts.
This International Standard is based on EN 1723:1999, prepared by CEN/TC 188.
This second edition cancels and replaces the first edition (ISO 21181:2005), of which it constitutes a
minor revision.
iv © ISO 2013 – All rights reserved

ISO 21181:2013(E)
Introduction
Many applications for light conveyor belts require that the belt is initially tensioned and there is no
subsequent change in belt length by adjustment of any rollers. In such cases, the tensioning force in the
belt changes throughout the life of the belt because of two effects: permanent stretch and relaxation
of the belt, both of which change its real elastic modulus. It is vital to have a means of establishing
the way in which the tensioning forces change; and this test applies a cyclic stretching between two
defined states of elongation over a large number of cycles. It has been found experimentally that the
tensioning force drops in an exponential way. It is possible to measure the tensioning force and then to
calculate what is defined in this International Standard as the “relaxed elastic modulus”. It is important
to note that this is not a true elastic modulus, because it includes an element of permanent stretch; but,
except in cases where the permanent stretch is relatively large, it is a measure of great practical value in
determining final tensioning forces. This International Standard is designed to meet the requirements
for such applications.
INTERNATIONAL STANDARD ISO 21181:2013(E)
Light conveyor belts — Determination of the relaxed
elastic modulus
1 Scope
This International Standard specifies a test method for the determination of the relaxed elastic modulus
of light conveyor belts according to ISO 21183-1 or other conveyor belts where ISO 9856 is not applicable.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 7500-1, Metallic materials — Verification of static uniaxial testing machines — Part 1: Tension/
compression testing machines — Verification and calibration of the force-measuring system
ISO 9856, Conveyor belts — Determination of elastic and permanent elongation and calculation of
elastic modulus
ISO 18573, Conveyor belts — Test atmospheres and conditioning periods
ISO 21183-1, Light conveyor belts — Part 1: Principal characteristics and applications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
elastic modulus
force per unit of width of a conveyor belt
Note 1 to entry: It is expressed in newtons per millimetre width of belt and is represented in ISO 9856 by the symbol M.
Note 2 to entry: This definition of the term deviates from that normally used in engineering, which is expressed in
units of stress, i.e. a force per unit of cross-section, and represented by the symbol E (see, for example, ISO 527-4).
3.2
elastic modulus
force in newtons per unit of width required to extend a representative
test piece of light conveyor belting by 1 % of its original length
Note 1 to entry: The force is represented by the symbol k and, consequently, the elastic modulus is represented by
the symbol k . This value is also called the “tensile force for 1 % elongation per unit of width” or “k value”. It
1% 1%
is expressed in newtons per millimetre.
Note 2 to entry: In EN 10002-1:2001, the symbol k is used to represent the coefficient of proportionality.
3.3
relaxed elastic modulus
elastic modulus of a light conveyor belt after being cycled between
predetermined limits of extension for 500 cycles
Note 1 to entry: The k value of a new conveyor belt is higher than that of a used conveyor belt in which relaxation
1%
has taken place in service. The relaxation takes place following an exponential function.
ISO 21181:201
...