EN ISO 16177:2012

Footwear - Resistance to crack initiation and growth - Belt flex method (ISO 16177:2012)

ISO 16177:2012 specifies a test method for determining the resistance of a component or material to crack initiation and growth due to repeated flexing. The method is mainly applicable to outsoles of footwear but may also be used with certain other flexible components.

Schuhe - Beständigkeit gegen Risserzeugung und Risswachstum - Verfahren mit flexiblem Band (ISO 16177:2012)

Diese Internationale Norm legt ein Prüfverfahren zur Bestimmung der Beständigkeit eines Bestandteils oder Werkstoffs gegen Risserzeugung und Risswachstum durch wiederholtes Biegen fest. Das Verfahren ist hauptsächlich auf Laufsohlen von Schuhen anwendbar, darf aber auch im Zusammenhang mit bestimmten anderen flexiblen Bestandteilen benutzt werden.

Chaussures - Résistance à la fissuration et à sa croissance - Méthode de flexion de la ceinture (ISO 16177:2012)

L'ISO 16177:2012 spécifie une méthode d'essai destinée à déterminer la résistance d'un composant ou d'un matériau au développement de gerçure ou à sa propagation causée par une flexion répétée. Cette méthode s'applique principalement aux semelles d'usure des chaussures, mais peut également être utilisée pour d'autres composants flexibles.

Obutev - Odpornost proti nastanku in širjenju razpok - Metoda s tračnim upogibanjem (ISO 16177:2012)

Ta mednarodni standard določa preskusno metodo za določanje odpornosti sestavnega dela ali materiala proti nastanku in širjenju razpok zaradi ponavljajočega se upogibanja. Metoda se uporablja predvsem za zunanje podplate pri obutvi, vendar se lahko uporabi tudi pri nekaterih drugih upogljivih sestavnih delih.

General Information

• Status: Published
• Publication Date: 30-Sep-2012
• Withdrawal Date: 29-Apr-2013
• ICS: 61.060 - Footwear
• Technical Committee: CEN/TC 309 - Footwear
• Drafting Committee: CEN/TC 309/WG 1 - Minimum performance requirements and test methods for components for footwear
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 01-Oct-2012
• Due Date: 01-Dec-2012
• Completion Date: 01-Oct-2012
• Ref Project: SIST EN ISO 16177:2013 - Footwear - Resistance to crack initiation and growth - Belt flex method (ISO 16177:2012)

Overview

EN ISO 16177:2012 - Footwear: Resistance to crack initiation and growth - Belt flex method specifies a laboratory test method to evaluate how components or materials (mainly outsoles) resist crack initiation and crack growth caused by repeated flexing. Published by CEN/ISO, the method replicates the short rapid flexing and longer unflexed periods experienced by footwear outsoles in use by mounting specimens on a driven cotton canvas belt and cycling them over crowned rollers.

Keywords: EN ISO 16177:2012, belt flex method, footwear testing, crack initiation, crack growth, outsole durability.

Key Topics and Technical Requirements

• Scope: Test method for outsole and other flexible footwear components to assess resistance to crack initiation and propagation under repeated flexing.
• Apparatus: Flexing machine with two crowned rollers (free-wheeling roller sized by sole thickness/expected service demand; driven roller 225 ± 5 mm diameter), and a continuous cotton canvas belt (~1930 mm length, 140 ± 5 mm width) with specified mass and tensile properties.
• Operating conditions: Belt speed and drive arranged to give approximately 90 ± 8 flexing cycles per minute (driven roller ~247 ± 20 r/min).
• Adhesives & surface prep: Use of a pre‑reacted PU adhesive and single‑component PU adhesive for bonding specimens to the belt. Material‑specific primers and surface treatments are required:
  • Halogenation primer for vulcanized/thermoplastic rubber
  • EVA primer for EVA materials
  • MEK wipe for PVC and solid thermoplastic PU
• Specimen preparation: Guidelines on cutting, thinning soles > 15 mm to 15 mm, surface scouring, and ageing (moulded specimens: wait ≥ 48 h before test).
• Bonding procedure: Heat-activate adhesive areas to 80–85 °C (verified with heat‑sensitive crayon), bond specimens, and condition the assembled belt ≥16 h at 23 ± 2 °C and 50 ± 2 % RH before cycling.
• Inspection & scoring: After flexing cycles, inspect and record cracks by position, length (nearest 1 mm) and depth classes:
  • Superficial: up to 0.5 mm
  • Shallow: 0.5–1.5 mm
  • Moderate: 1.5 mm to half specimen thickness
  • Deep: greater than half specimen thickness

Applications and Users

• Footwear manufacturers for quality control and production acceptance testing of outsoles.
• Material suppliers (rubber, PU, EVA) for validating formulation durability under flex fatigue.
• Test laboratories and certification bodies performing standardized durability tests for product claims.
• R&D and product development teams using results to compare designs, select materials, or troubleshoot cracking/failure modes.
• Compliance officers ensuring products meet market or contract durability requirements.

Related Standards

• ISO 20344 (referenced for specimen marking/figures)
• Prepared under collaboration between CEN/TC 309 and ISO/TC 216 (Footwear)

EN ISO 16177:2012 remains a practical, reproducible method for assessing outsole flex fatigue resistance and supporting product development, material selection, and conformity testing in the footwear industry.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2013
2EXWHY2GSRUQRVWSURWLQDVWDQNXLQãLUMHQMXUD]SRN0HWRGDVWUDþQLP
XSRJLEDQMHP,62
Footwear - Resistance to crack initiation and growth - Belt flex method (ISO 16177:2012)
Schuhe - Prüfverfahren für Laufsohlen - Beständigkeit gegen Risserzeugung und
Risswachstum mit dem Verfahren mit flexiblem Band (ISO 16177:2012)
Chaussures - Résistance à la fissuration et à sa croissance - Méthode de flexion de la
ceinture (ISO 16177:2012)
Ta slovenski standard je istoveten z: EN ISO 16177:2012
ICS:
61.060 Obuvala Footwear
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 16177
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2012
ICS 61.060
English Version
Footwear - Resistance to crack initiation and growth - Belt flex
method (ISO 16177:2012)
Chaussures - Résistance à la fissuration et à sa croissance Schuhe - Beständigkeit gegen Risserzeugung und
- Méthode de flexion de la ceinture (ISO 16177:2012) Risswachstum - Verfahren mit flexiblem Band (ISO
16177:2012)
This European Standard was approved by CEN on 30 September 2012.

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
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 16177:2012: E
worldwide for CEN national Members.

Contents Page
Foreword .3
Foreword
This document (EN ISO 16177:2012) has been prepared by Technical Committee CEN/TC 309 “Footwear”,
the secretariat of which is held by AENOR, in collaboration with Technical Committee ISO/TC 216 "Footwear".
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 April 2013, and conflicting national standards shall be withdrawn at the
latest by April 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.
According to the CEN/CENELEC Internal Regulations, the national standards organisations 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.

INTERNATIONAL ISO
STANDARD 16177
First edition
2012-10-01
Footwear — Resistance to crack initiation
and growth — Belt flex method
Chaussures — Résistance à la fissuration et à sa croissance —
Méthode de flexion de la ceinture
Reference number
ISO 16177:2012(E)
©
ISO 2012
ISO 16177:2012(E)
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO’s
member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved

ISO 16177:2012(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.
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.
ISO 16177 was prepared by the European Committee for Standardization (CEN) Technical Committee
CEN/TC 309, Footwear, in collaboration with ISO Technical Committee ISO/TC 216, Footwear, in accordance
with the agreement on technical cooperation between ISO and CEN (Vienna Agreement).
INTERNATIONAL STANDARD ISO 16177:2012(E)
Footwear — Resistance to crack initiation and growth — Belt
flex method
1 Scope
This International Standard specifies a test method for determining the resistance of a component or material
to crack initiation and growth due to repeated flexing. The method is mainly applicable to outsoles of footwear
but may also be used with certain other flexible components.
2 Apparatus and materials
2.1 Flexing machine with:
2.1.1 Free wheeling, slightly crowned flexing roller, with a width of (170 ± 20) mm and
— for high performance soles,
diameter at its centre (60,0 ± 0,5) mm,
diameter at its ends (57 ± 1) mm;
NOTE This roller will normally only be used for footwear which is expected to be subjected to abnormally high
flexing demands.
— for typical sole units,
diameter at its centre (90,0 ± 0,5) mm,
diameter at its ends (87 ± 1) mm;
— for soles with a thickness greater than 15 mm,
diameter at its centre (120,0 ± 0,5) mm,
diameter at its ends (117 ± 1) mm.
2.1.2 Driven, slightly crowned roller, with a diameter of (225 ± 5) mm and a width of (170 ± 20) mm.
2.1.3 Flexible continuous belt of cotton canvas of length (1 930 ± 50) mm and width (140 ± 5) mm which
passes over the two rollers (2.1.1) and (2.1.2). The cotton canvas is 2-ply 100 % cotton belting having a mass
per unit area of (500 ± 25) g/m and an extension at break along the belt of (14 ± 2) % at a breaking force of (2
000 ± 200) N. The corresponding across-the-belt values are (14 ± 2) % and (750 ± 50) N.
2.1.4 Means of driving the larger roller (2.1.2) at a speed of (247 ± 20) r/min so that the belt (2.1.3)
completes (90 ± 8) flexing cycles per minute.
2.1.5 Method of counting the number of cycles completed by the belt (2.1.3).
2.2 Polyurethane adhesive system to bond the test specimen to the surface of the belt (2.1.3), consisting of:
2.2.1 Pre-reacted PU adhesive.
2.2.2 Single-component PU adhesive.
ISO 16177:2012(E)
2.3 Cutting device, such as a sharp knife or scalpel, capable of cutting test specimens.
2.4 Smooth-surfaced hand tool for the application of localized pressure by a rubbing action.
NOTE A rapid acting platen press with the capability of applying a pressure of (500 ± 50) kPa over the whole area of
the test specimen may be suitable for some types of sole specimen.
2.5 Means of heating adhesive film, for activating adhesive film or removing samples from the belt. This
can be achieved by using a hot air gun or an oven set at 50 °C. Heat should be applied in short bursts to prevent
partial melting of soles.
NOTE Commercial equipment for heat reactivating outsoles and uppers in production is suitable.
2.6 Method of checking that the temperature of the adhesive film is within the range between 80 °C and
1)
90 °C. Heat sensitive crayons, such as Tempilstik , are suitable, preferably with a melting temperature of 83 °C.
2.7 Primers.
2.7.1 Vulcanized and thermoplastic rubber test specimens. A halogenation primer for rubber will be
necessary for producing satisfactory bonds.
2.7.2 EVA test specimens. An EVA primer will be necessary for producing satisfactory bonds.
2.8 Device, such as a T square, with an internal angle of (90 ± 1)°.
2.9 Device for checking whether the depth of a crack is greater than 1,5 mm. A thin strip of metal with a
length scale or stepped thickness is suitable.
3 Principle
A test specimen is bonded with a strong adhesive to a continuous belt, which is driven around two rollers. The
spacing
...