Textiles - Determination of the elasticity of fabrics - Part 1: Strip tests (ISO 20932-1:2018)

This document describes the methods of test using strips of fabric in straight strip form or as loops, which can be used to measure elasticity and related properties of fabrics, excluding narrow fabrics.

Textilien - Bestimmung der Elastizität von textilen Flächengebilden - Teil 1: Streifenprüfungen (ISO 20932-1:2018)

Dieses Dokument beschreibt die Prüfverfahren, die an Streifen von textilen Flächengebilden, ausgelegt als gerade Streifen oder in Schlaufen, zum Messen der Elastizität und damit verbundener Eigenschaften von textilen Flächengebilden, mit Ausnahme von Schmaltextilien, verwendet werden können.

Textiles - Détermination de l'élasticité des étoffes - Partie 1: Essais sur bande (ISO 20932-1:2018)

Le présent document décrit des méthodes d'essai utilisant des bandes droites d'étoffes ou en boucles, qui peuvent être utilisées pour mesurer l'élasticité et les propriétés connexes des étoffes, à l'exclusion des étoffes étroites.

Tekstilije - Ugotavljanje elastičnosti tkanin - 1. del: Preskusi traku (ISO 20932-1:2018)

General Information

Status
Published
Publication Date
25-Feb-2020
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
26-Feb-2020
Completion Date
26-Feb-2020

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SLOVENSKI STANDARD
SIST EN ISO 20932-1:2020
01-maj-2020
Nadomešča:
SIST EN 14704-1:2005

Tekstilije - Ugotavljanje elastičnosti tkanin - 1. del: Preskusi traku (ISO 20932-

1:2018)

Textiles - Determination of the elasticity of fabrics - Part 1: Strip tests (ISO 20932-

1:2018)
Textilien - Bestimmung der Elastizität von textilen Flächengebilden - Teil 1:
Streifenprüfungen (ISO 20932-1:2018)

Textiles - Détermination de l'élasticité des étoffes - Partie 1: Essais sur bande (ISO

20932-1:2018)
Ta slovenski standard je istoveten z: EN ISO 20932-1:2020
ICS:
59.080.01 Tekstilije na splošno Textiles in general
SIST EN ISO 20932-1:2020 en

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

---------------------- Page: 1 ----------------------
SIST EN ISO 20932-1:2020
---------------------- Page: 2 ----------------------
SIST EN ISO 20932-1:2020
EN ISO 20932-1
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2020
EUROPÄISCHE NORM
ICS 59.080.30 Supersedes EN 14704-1:2005
English Version
Textiles - Determination of the elasticity of fabrics - Part 1:
Strip tests (ISO 20932-1:2018)

Textiles - Détermination de l'élasticité des étoffes - Textilien - Bestimmung der Elastizität von textilen

Partie 1: Essais sur bande (ISO 20932-1:2018) Flächengebilden - Teil 1: Streifenprüfungen (ISO

20932-1:2018)
This European Standard was approved by CEN on 11 November 2019.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 20932-1:2020 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 20932-1:2020
EN ISO 20932-1:2020 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

---------------------- Page: 4 ----------------------
SIST EN ISO 20932-1:2020
EN ISO 20932-1:2020 (E)
European foreword

The text of ISO 20932-1:2018 has been prepared by Technical Committee ISO/TC 38 "Textiles” of the

International Organization for Standardization (ISO) and has been taken over as EN ISO 20932-1:2020

by Technical Committee CEN/TC 248 “Textiles and textile products” the secretariat of which is held by

BSI.

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 2020, and conflicting national standards shall

be withdrawn at the latest by August 2020.

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

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

This document supersedes EN 14704-1:2005.

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, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 20932-1:2018 has been approved by CEN as EN ISO 20932-1:2020 without any

modification.
---------------------- Page: 5 ----------------------
SIST EN ISO 20932-1:2020
---------------------- Page: 6 ----------------------
SIST EN ISO 20932-1:2020
INTERNATIONAL ISO
STANDARD 20932-1
First edition
2018-11
Textiles — Determination of the
elasticity of fabrics —
Part 1:
Strip tests
Textiles — Détermination de l'élasticité des étoffes —
Partie 1: Essais sur bande
Reference number
ISO 20932-1:2018(E)
ISO 2018
---------------------- Page: 7 ----------------------
SIST EN ISO 20932-1:2020
ISO 20932-1:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 20932-1:2020
ISO 20932-1:2018(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 3

5 Sampling ........................................................................................................................................................................................................................ 3

6 Apparatus ..................................................................................................................................................................................................................... 4

7 Atmosphere for conditioning and testing .................................................................................................................................. 5

8 Preparation of test specimens ................................................................................................................................................................ 5

8.1 General ........................................................................................................................................................................................................... 5

8.2 Test specimen preparation ........................................................................................................................................................... 5

8.2.1 Woven fabrics ..................................................................................................................................................................... 5

8.2.2 Knitted fabrics .................................................................................................................................................................... 6

8.2.3 Nonwoven fabrics ........................................................................................................................................................... 7

9 Procedure..................................................................................................................................................................................................................... 8

9.1 Woven and nonwoven fabrics (other than knitted) ................................................................................................ 8

9.1.1 Method A — Strip test specimens ..................................................................................................................... 8

9.1.2 Method B — Loop test specimens .................................................................................................................... 8

9.2 Knitted fabrics ......................................................................................................................................................................................... 8

9.2.1 Method A — Strip test specimens ..................................................................................................................... 8

9.2.2 Method B — Loop test specimens .................................................................................................................... 9

9.3 Operation ..................................................................................................................................................................................................... 9

10 Recording ..................................................................................................................................................................................................................10

11 Expressions and calculations of test results .........................................................................................................................10

12 Test report ................................................................................................................................................................................................................11

Annex A (informative) Example of a typical cycling graph .........................................................................................................13

Annex B (informative) Procedure for sampling .....................................................................................................................................14

Annex C (informative) Clamping and holding devices ....................................................................................................................15

Annex D (informative) Example of a pattern for cutting test specimens from a laboratory

sample ..........................................................................................................................................................................................................................17

Bibliography .............................................................................................................................................................................................................................18

© ISO 2018 – All rights reserved iii
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SIST EN ISO 20932-1:2020
ISO 20932-1:2018(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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).

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

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following

URL: www .iso .org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 38, Textiles, Subcommittee SC 24,

Conditioning atmospheres and physical tests for textile fabrics.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/members .html.
A list of all parts in the ISO 20932 series can be found on the ISO website.
iv © ISO 2018 – All rights reserved
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SIST EN ISO 20932-1:2020
ISO 20932-1:2018(E)
Introduction

This document was developed as a result of technical advancements in yarn and fabric structures and

properties, which increase product range and developments.
[1]
This document is based on EN 14704-1 .
© ISO 2018 – All rights reserved v
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SIST EN ISO 20932-1:2020
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SIST EN ISO 20932-1:2020
INTERNATIONAL STANDARD ISO 20932-1:2018(E)
Textiles — Determination of the elasticity of fabrics —
Part 1:
Strip tests
1 Scope

This document describes the methods of test using strips of fabric in straight strip form or as loops,

which can be used to measure elasticity and related properties of fabrics, excluding narrow fabrics.

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.

ISO 139, Textiles — Standard atmospheres for conditioning and testing
ISO 4915, Textiles — Stitch types — Classification and terminology

ISO 7500-1, Metallic materials — Verification of static uniaxial testing machines — Part 1: Tension/

compression testing machines — Calibration and verification of the force-measuring system

ISO 10012, Measurement management systems — Requirements for measurement processes and measuring

equipment
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
narrow fabric

woven or knitted construction intended for use as a trim, binding, edging, strapping or harness, and

designed to be used in its full width
3.2
elasticity

ability to recover original size and shape immediately after the removal of the force causing

deformation
3.3
constant-rate-of-extension testing machine
CRE testing machine

tensile testing machine provided with one clamp, which is stationary, and another clamp, which moves

with a constant speed throughout the test, the entire testing system being virtually free from deflection

© ISO 2018 – All rights reserved 1
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SIST EN ISO 20932-1:2020
ISO 20932-1:2018(E)
3.4
strip test specimen

test specimen in which the full width is gripped in the jaws of the testing machine

3.5
loop test specimen

test specimen in which a seam is made to create a loop of the full width of the specimen and which is

placed around a loop bar assembly positioned on the testing machine

Note 1 to entry: This method of preparation is useful when any ageing or exposure testing is to be carried out on

the specimens after measurement.
3.6
gauge length

distance between the two effective clamping or holding points of a testing device

Note 1 to entry: For strip tests, method A: distance between the two contact points of the line clamps.

Note 2 to entry: For loop tests, method B: half of the circumference around the loop bar assembly.

3.7
slack mounting

insertion of a strip test specimen (3.4) in the line clamps of the upper jaw, allowing it to hang freely

under its own weight, guided by the hand to ensure perpendicular alignment to the line of pulling force,

without any force being applied
3.8
initial length

length of the test specimen between the two effective clamping or holding points, at the beginning of

the test (after slack mounting (3.7) or under specified pretension)
3.9
pretension
force applied to a test specimen at the beginning of certain tests

Note 1 to entry: Pretension is used to determine the initial length of the test specimen.

[SOURCE: ISO 13934-1:2013, 3.5, modified — References to 3.4 and 3.7 have been removed from Note 1

to entry.]
3.10
extension
increase in length of a test specimen during testing
Note 1 to entry: Extension is expressed in units of the length.
3.11
elongation
ratio of the extension (3.10) of the test specimen to its initial length
Note 1 to entry: Elongation is expressed as a percentage.
3.12
maximum force
force at the position when a test specimen is taken to a fixed extension (3.10)
Note 1 to entry: Maximum force is expressed in newtons.
3.13
maximum extension

extension (3.10) recorded in millimetres at the position when a test specimen is taken to a fixed load

Note 1 to entry: Maximum extension is expressed in units of the length.
2 © ISO 2018 – All rights reserved
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SIST EN ISO 20932-1:2020
ISO 20932-1:2018(E)
3.14
force at specified elongation
force measured at a given elongation (3.11) on either the load or unload curves
3.15
cycle

process whereby a fabric is taken from the gauge length (3.6) to a fixed load or fixed extension or

elongation and returned to gauge length
3.16
force decay due to time

loss of force measured over time when a test specimen is stretched to a specified elongation or force

and held at this position for a given time period

Note 1 to entry: The decay in force is expressed as a percentage of the original force recorded at the specified

position (see Annex A, Figure A.1).
3.17
force decay due to exercising

loss of force, calculated and expressed as a percentage, as measured and recorded at the same elongation

point on two different cycles when the test specimen is cycled several times between the gauge length

(3.6) and a specified elongation
Note 1 to entry: See Annex A, Figure A.1.
3.18
permanent deformation

ratio of unrecovered extension of the test specimen after cycling (to a specified force or specified

extension) to its initial length
Note 1 to entry: Permanent deformation is expressed as a percentage.
3.19
recovered elongation
complement of permanent deformation (3.18) to 100 %
Note 1 to entry: Recovered elongation is expressed as a percentage.
3.20
elastic recovery
recovered elongation (3.19) of the total elongation
Note 1 to entry: Elastic recovery is expressed as a percentage.
4 Principle

A fabric test specimen of specified dimensions is extended at a constant rate to either a specified

force or elongation for an agreed number of cycles, and its elasticity determined by measuring certain

characteristics.
5 Sampling

Fabric samples shall be selected in accordance with the product specification. In the absence of a

product specification for the fabric, the sampling method given in Annex B may be used.

© ISO 2018 – All rights reserved 3
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SIST EN ISO 20932-1:2020
ISO 20932-1:2018(E)
6 Apparatus
6.1 CRE testing machine.

Metrological confirmation system of the tensile testing machine shall be in accordance with ISO 10012.

The constant-rate-of-extension (CRE) testing machine shall conform to the following.

a) The tensile testing machine shall be provided with the means for indicating or recording the force

and elongation values when cycling between gauge length and either a fixed load or fixed extension.

Under conditions of use, the accuracy of the apparatus shall be at least class 1 of ISO 7500-1. The

error of the indicated or recorded maximum force at any point in the range in which the machine

is used shall not exceed 1 %, and the error of the indicated or recorded jaw separation shall not

exceed 1 mm.

b) If recording of force or elongation is obtained by means of data acquisition boards and software,

the frequency of data collection shall be at least eight per second.

c) The machine shall be capable of constant rates of extension including 20 mm/min to 500 mm/min

with an accuracy of ±10 %.

d) The machine shall be capable of variable gauge length settings including 100 mm to 250 mm, to an

accuracy of ±1 mm.

e) The clamping or holding devices shall be positioned with their central point in line of the applied

force. The machine shall be calibrated with the clamping or holding devices in position and the jaw

faces closed, where applicable.
6.2 Line clamps (for method A).

The jaws shall be capable of holding the test specimen without allowing it to slip and designed so that

they do not cut or otherwise weaken the test specimen.

Line clamps, as shown in Annex C, Figure C.1, shall consist of two jaws, one being of steel plate, the

other having a convex 3 mm radius. The line of contact of the jaws shall be perpendicular to the line of

increasing force. The clamping faces shall be in the same plane.
The line clamp jaws shall not be less than the width of the test specimen.

NOTE Significant levels of work have shown this type of line clamp is the preferred type for elastane/

elastodiene containing fabrics as fabric slippage is insignificant. If a fabric slips, the elongation values are

inaccurate.

Pneumatic operated grips are recommended as hand tightening of manual grips can cause distortion

of the test specimen. The air pressure should be sufficient to prevent slippage when compensating the

decreasing thickness of the fabric but should not cut or otherwise weaken the test specimen.

6.3 Loop bar assembly (for method B).

The loop bar assembly shall be as shown in Annex C, Figure C.2 a) or b) and typically comprises two

steel bars of circular cross-section and the diameter between 4 mm and 8 mm. The specimen is looped

over these bars and extended as the bars move apart. The axes of the bars shall be perpendicular to the

line of increasing force. The steel bar holders shall have a minimum internal dimension of 80 mm.

6.4 Equipment, for cutting test specimens and for fraying, where applicable to the required

dimensions.

6.5 Sewing machine, capable of producing a type 301 lockstitch as defined in ISO 4915, furnished

with a medium ballpoint needle (90s SUK) and 470 decitex (ticket 75’s) polyester core-spun thread.

4 © ISO 2018 – All rights reserved
---------------------- Page: 16 ----------------------
SIST EN ISO 20932-1:2020
ISO 20932-1:2018(E)

NOTE If there is a risk of damage to the fabric, a finer needle and corresponding polyester core spun thread

can be used.
6.6 Calibrated metal rule, graduated in millimetres.
7 Atmosphere for conditioning and testing

The atmospheres for preconditioning, conditioning and testing shall be as specified in ISO 139.

The fabric samples shall be conditioned for a minimum of 20 h in a tension free state. The prepared test

specimens shall be conditioned in a tension free state for a further 4 h after preparation, to minimize

the effects of handling during preparation.
8 Preparation of test specimens
8.1 General

From each laboratory sample, a set of test specimens shall be cut in the direction(s) of the stretch.

A set shall consist of a minimum of five test specimens. No test specimen shall be cut from within

150 mm of either edge of the laboratory sample. No test specimen taken from the longitudinal direction

shall contain the same yarns and no test specimen taken from the transversal direction shall contain

the same yarns unless otherwise specified between interested parties.

NOTE An example of a suitable pattern for cutting test specimens from laboratory sample is given in

Annex D, Figure D.1.
8.2 Test specimen preparation
8.2.1 Woven fabrics
8.2.1.1 Strip test specimens (for method A)

Each test specimen shall be cut with its length parallel to the warp or the weft of the fabric and

shall be sufficiently wide to allow the necessary fringes on both sides. Threads shall be removed in

approximately equal numbers from each of the long edges of the cut strip to create fringes, until a width

(not including the fringes) of (50,0 ± 1,0) mm or 1 complete thread, is achieved. The width of fringes

shall be such that during testing no longitudinal threads escape the fringes. The length of the specimen

shall be cut between 250 mm and 300 mm.

NOTE For the majority of fabrics, fringes of a width approximately 5 mm or 15 threads is sufficient. For very

closely woven fabrics, a much narrower fringe might be satisfactory. Fabrics of very open weave can require up

to 10 mm.

For fabrics, which cannot be frayed in this manner, test specimens shall be cut along lines (50,0 ± 1,0) mm

apart and parallel to the machine or the cross-machine direction.

For fabrics in form of band with a maximum width of 100 mm, test specimen can be tested in full width

without fraying them.

If permanent deformation is to be determined at the end of the test, place 100 mm reference (bench)

marks parallel to the specimen short side, centrally on the specimen.

If a pretension is used, placing of reference marks is not required, since the length at pretension is used

for calculation.
© ISO 2018 – All rights reserved 5
---------------------- Page: 17 ----------------------
SIST EN ISO 20932-1:2020
ISO 20932-1:2018(E)
8.2.1.2 Loop test specimens (for method B)

Each test specimen shall be cut with its length parallel to the warp or the weft of the fabric and

shall be sufficiently wide to allow the necessary fringes on both sides. Threads shall be removed in

approximately equal numbers from each of the long edges of the cut strip to create fringes, until a

width (not including the fringes) of (75,0 ± 1,0) mm or one complete thread, is achieved. The length

of the specimen shall be cut to (250 ± 1) mm. The width of fringes shall be such that during testing no

longitudinal threads escape the fringes.

A fine stitch line shall be marked 25 mm from one end and then a further fine stitch line marked at

a distance of 200 mm from the first line. The specimen shall be folded in half, parallel to the short

dimension lining up the stitch lines.

Using a type 301 lockstitch, starting in the centre of the stitch line, the test specimen shall be sewn along

the line to one edge, turned at the edge, without cutting the sewing threads, and sewn along the same

line, then turned at the other edge and sewn to the centre. The stitch density shall be 3,5 ± 0,5 per cm.

NOTE 1 For the majority of fabrics, fringes of a width approximately 5 mm or 15 threads is sufficient. For very

closely woven fabrics, a much narrower fringe might be satisfactory. Fabrics of very open weave can require up

to 10 mm.

For fabrics, which cannot be frayed in this manner, test specimens shall be cut along lines (75,0 ± 1,0) mm

apart and parallel to the machine or the cross-machine direction.

NOTE 2 Accurate preparation of the loop test specimens in this manner ensures correct fit of the specimen

circumference around the loop assembly bars, preventing too tight or too slack a fit.

If permanent deformation is to be determined at the end of the test, place 100 mm reference (bench)

marks parallel to the specimen short side, centrally on the specimen.
If a pretension is used, placing of reference marks is not requi
...

SLOVENSKI STANDARD
oSIST prEN ISO 20932-1:2019
01-julij-2019

Tekstilije - Ugotavljanje elastičnosti tkanin - 1. del: Preskusi traku (ISO 20932-

1:2018)

Textiles - Determination of the elasticity of fabrics - Part 1: Strip tests (ISO 20932-

1:2018)

Textiles - Détermination de l'élasticité des étoffes - Partie 1: Essais sur bande (ISO

20932-1:2018)
Ta slovenski standard je istoveten z: prEN ISO 20932-1
ICS:
59.080.01 Tekstilije na splošno Textiles in general
oSIST prEN ISO 20932-1:2019 en

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

---------------------- Page: 1 ----------------------
oSIST prEN ISO 20932-1:2019
---------------------- Page: 2 ----------------------
oSIST prEN ISO 20932-1:2019
INTERNATIONAL ISO
STANDARD 20932-1
First edition
2018-11
Textiles — Determination of the
elasticity of fabrics —
Part 1:
Strip tests
Textiles — Détermination de l'élasticité des étoffes —
Partie 1: Essais sur bande
Reference number
ISO 20932-1:2018(E)
ISO 2018
---------------------- Page: 3 ----------------------
oSIST prEN ISO 20932-1:2019
ISO 20932-1:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 20932-1:2019
ISO 20932-1:2018(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 3

5 Sampling ........................................................................................................................................................................................................................ 3

6 Apparatus ..................................................................................................................................................................................................................... 4

7 Atmosphere for conditioning and testing .................................................................................................................................. 5

8 Preparation of test specimens ................................................................................................................................................................ 5

8.1 General ........................................................................................................................................................................................................... 5

8.2 Test specimen preparation ........................................................................................................................................................... 5

8.2.1 Woven fabrics ..................................................................................................................................................................... 5

8.2.2 Knitted fabrics .................................................................................................................................................................... 6

8.2.3 Nonwoven fabrics ........................................................................................................................................................... 7

9 Procedure..................................................................................................................................................................................................................... 8

9.1 Woven and nonwoven fabrics (other than knitted) ................................................................................................ 8

9.1.1 Method A — Strip test specimens ..................................................................................................................... 8

9.1.2 Method B — Loop test specimens .................................................................................................................... 8

9.2 Knitted fabrics ......................................................................................................................................................................................... 8

9.2.1 Method A — Strip test specimens ..................................................................................................................... 8

9.2.2 Method B — Loop test specimens .................................................................................................................... 9

9.3 Operation ..................................................................................................................................................................................................... 9

10 Recording ..................................................................................................................................................................................................................10

11 Expressions and calculations of test results .........................................................................................................................10

12 Test report ................................................................................................................................................................................................................11

Annex A (informative) Example of a typical cycling graph .........................................................................................................13

Annex B (informative) Procedure for sampling .....................................................................................................................................14

Annex C (informative) Clamping and holding devices ....................................................................................................................15

Annex D (informative) Example of a pattern for cutting test specimens from a laboratory

sample ..........................................................................................................................................................................................................................17

Bibliography .............................................................................................................................................................................................................................18

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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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www. iso. org/directives).

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

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following

URL: www .iso .org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 38, Textiles, Subcommittee SC 24,

Conditioning atmospheres and physical tests for textile fabrics.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/members .html.
A list of all parts in the ISO 20932 series can be found on the ISO website.
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Introduction

This document was developed as a result of technical advancements in yarn and fabric structures and

properties, which increase product range and developments.
[1]
This document is based on EN 14704-1 .
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INTERNATIONAL STANDARD ISO 20932-1:2018(E)
Textiles — Determination of the elasticity of fabrics —
Part 1:
Strip tests
1 Scope

This document describes the methods of test using strips of fabric in straight strip form or as loops,

which can be used to measure elasticity and related properties of fabrics, excluding narrow fabrics.

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.

ISO 139, Textiles — Standard atmospheres for conditioning and testing
ISO 4915, Textiles — Stitch types — Classification and terminology

ISO 7500-1, Metallic  materials  —  Verification  of  static  uniaxial  testing  machines  —  Part  1:  Tension/

compression testing machines — Calibration and verification of the force-measuring system

ISO 10012, Measurement management systems — Requirements for measurement processes and measuring

equipment
3 Terms a nd definiti ons
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:/ /www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
narrow fabric

woven or knitted construction intended for use as a trim, binding, edging, strapping or harness, and

designed to be used in its full width
3.2
elasticity

ability to recover original size and shape immediately after the removal of the force causing

deformation
3.3
constant-rate-of-extension testing machine
CRE testing machine

tensile testing machine provided with one clamp, which is stationary, and another clamp, which moves

with a constant speed throughout the test, the entire testing system being virtually free from deflection

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3.4
strip test specimen

test specimen in which the full width is gripped in the jaws of the testing machine

3.5
loop test specimen

test specimen in which a seam is made to create a loop of the full width of the specimen and which is

placed around a loop bar assembly positioned on the testing machine

Note 1 to entry: This method of preparation is useful when any ageing or exposure testing is to be carried out on

the specimens after measurement.
3.6
gauge length

distance between the two effective clamping or holding points of a testing device

Note 1 to entry: For strip tests, method A: distance between the two contact points of the line clamps.

Note 2 to entry: For loop tests, method B: half of the circumference around the loop bar assembly.

3.7
slack mounting

insertion of a strip test specimen (3.4) in the line clamps of the upper jaw, allowing it to hang freely

under its own weight, guided by the hand to ensure perpendicular alignment to the line of pulling force,

without any force being applied
3.8
initial length

length of the test specimen between the two effective clamping or holding points, at the beginning of

the test (after slack mounting (3.7) or under specified pretension)
3.9
pretension
force applied to a test specimen at the beginning of certain tests

Note 1 to entry: Pretension is used to determine the initial length of the test specimen.

[SOURCE: ISO 13934-1:2013, 3.5, modified — References to 3.4 and 3.7 have been removed from Note 1

to entry.]
3.10
extension
increase in length of a test specimen during testing
Note 1 to entry: Extension is expressed in units of the length.
3.11
elongation
ratio of the extension (3.10) of the test specimen to its initial length
Note 1 to entry: Elongation is expressed as a percentage.
3.12
maximum force
force at the position when a test specimen is taken to a fixed extension (3.10)
Note 1 to entry: Maximum force is expressed in newtons.
3.13
maximum extension

extension (3.10) recorded in millimetres at the position when a test specimen is taken to a fixed load

Note 1 to entry: Maximum extension is expressed in units of the length.
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3.14
f or c e at s p e c i f ie d elon g at ion
force measured at a given elongation (3.11) on either the load or unload curves
3.15
cycle

process whereby a fabric is taken from the gauge length (3.6) to a fixed load or fixed extension or

elongation and returned to gauge length
3.16
force decay due to time

loss of force measured over time when a test specimen is stretched to a specified elongation or force

and held at this position for a given time period

Note 1 to entry: The decay in force is expressed as a percentage of the original force recorded at the specified

position (see Annex A, Figure A.1).
3.17
force decay due to exercising

loss of force, calculated and expressed as a percentage, as measured and recorded at the same elongation

point on two different cycles when the test specimen is cycled several times between the gauge length

(3.6) and a specified elongation
Note 1 to entry: See Annex A, Figure A.1.
3.18
permanent deformation

ratio of unrecovered extension of the test specimen after cycling (to a specified force or specified

extension) to its initial length
Note 1 to entry: Permanent deformation is expressed as a percentage.
3.19
recovered elongation
complement of permanent deformation (3.18) to 100 %
Note 1 to entry: Recovered elongation is expressed as a percentage.
3.20
elastic recovery
recovered elongation (3.19) of the total elongation
Note 1 to entry: Elastic recovery is expressed as a percentage.
4 Principle

A fabric test specimen of specified dimensions is extended at a constant rate to either a specified

force or elongation for an agreed number of cycles, and its elasticity determined by measuring certain

characteristics.
5 Sampling

Fabric samples shall be selected in accordance with the product specification. In the absence of a

product specification for the fabric, the sampling method given in Annex B may be used.

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6 Apparatus
6.1 CRE testing machine.

Metrological confirmation system of the tensile testing machine shall be in accordance with ISO 10012.

The constant-rate-of-extension (CRE) testing machine shall conform to the following.

a) The tensile testing machine shall be provided with the means for indicating or recording the force

and elongation values when cycling between gauge length and either a fixed load or fixed extension.

Under conditions of use, the accuracy of the apparatus shall be at least class 1 of ISO 7500-1. The

error of the indicated or recorded maximum force at any point in the range in which the machine

is used shall not exceed 1 %, and the error of the indicated or recorded jaw separation shall not

exceed 1 mm.

b) If recording of force or elongation is obtained by means of data acquisition boards and software,

the frequency of data collection shall be at least eight per second.

c) The machine shall be capable of constant rates of extension including 20 mm/min to 500 mm/min

with an accuracy of ±10 %.

d) The machine shall be capable of variable gauge length settings including 100 mm to 250 mm, to an

accuracy of ±1 mm.

e) The clamping or holding devices shall be positioned with their central point in line of the applied

force. The machine shall be calibrated with the clamping or holding devices in position and the jaw

faces closed, where applicable.
6.2 Line clamps (for method A).

The jaws shall be capable of holding the test specimen without allowing it to slip and designed so that

they do not cut or otherwise weaken the test specimen.

Line clamps, as shown in Annex C, Figure C.1, shall consist of two jaws, one being of steel plate, the

other having a convex 3 mm radius. The line of contact of the jaws shall be perpendicular to the line of

increasing force. The clamping faces shall be in the same plane.
The line clamp jaws shall not be less than the width of the test specimen.

NOTE Significant levels of work have shown this type of line clamp is the preferred type for elastane/

elastodiene containing fabrics as fabric slippage is insignificant. If a fabric slips, the elongation values are

inaccurate.

Pneumatic operated grips are recommended as hand tightening of manual grips can cause distortion

of the test specimen. The air pressure should be sufficient to prevent slippage when compensating the

decreasing thickness of the fabric but should not cut or otherwise weaken the test specimen.

6.3 Loop bar assembly (for method B).

The loop bar assembly shall be as shown in Annex C, Figure C.2 a) or b) and typically comprises two

steel bars of circular cross-section and the diameter between 4 mm and 8 mm. The specimen is looped

over these bars and extended as the bars move apart. The axes of the bars shall be perpendicular to the

line of increasing force. The steel bar holders shall have a minimum internal dimension of 80 mm.

6.4 Equipment, for cutting test specimens and for fraying, where applicable to the required

dimensions.

6.5 Sewing machine, capable of producing a type 301 lockstitch as defined in ISO 4915, furnished

with a medium ballpoint needle (90s SUK) and 470 decitex (ticket 75’s) polyester core-spun thread.

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NOTE If there is a risk of damage to the fabric, a finer needle and corresponding polyester core spun thread

can be used.
6.6 Calibrated metal rule, graduated in millimetres.
7 Atmosphere for conditioning and testing
The atmospheres for pre
...

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