ISO INTERNATIONAL STANDARD 7854 Second edition 1995-08-15 Rubber- or plastics-coated fabrics Determination of resistance to damage by flexing Supports textiles revetus de caoutchouc ou de plastique -Détermination delarésistancealaflexion ISO Reference number ISO 7854:1995(E) Copyright International Organization for Standardization ISO 7854:1995(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 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. 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 International Standard ISO 7854 was prepared by Technicai Committee ISO/TC45,Rubberand rubberproducts. 1984), which has been technically revised. Annex A of this International Standard is for information only. ISO 1995 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 the publisher. International Organization for Standardization Case Postale 56 · CH-1211 Geneve 20 · Switzerland Printed in Switzerland for Standardizatior by IHS t No reproduction or networking permited without license from IHS Not or Resale CISO IS0 7854:1995(E) Introduction a number of years suffered from poor repeatability (due in part to the un- known but inevitable variability of the material tested) and worse reproducibility. Nevertheless, dynamic-flex performance of coated fabrics has been long and widely used as a measure of the product quality. The methods traditionally used suffered from the common deficiency of testing only a small test piece. The De Mattia test is unsuitable for ma- terials that exhibit "set",such as thermoplastics,and the Schildknecht method has disadvantages when testing the heavier industrial fabrics and also tends to require very high geometric ratios and consequently time- consuming tests to verify results. In addition, themounting 01 Schildknecht test pieces can seriously affect test results and repeatability. Both the De Mattia and Schildknecht methods are also uni-directional. ate, e.g. where bi-directional stresses are exerted during use. difficulties associated with the Schildknecht apparatus (method B) and in- troduces a bi-directional flex fatigue test that provides a large test piece, enabling post-flexing investigations, such as hydrostatic-head tests, to be conducted. The apparatus is described in ISO 8096-3:1988, Rubber- or plastics-coated fabrics for water-resistant clothing - -Specification 'Part 3: Natural rubber- and synthetic rubber-coated fabrics. The apparatus outlined there in illustrative form (see the note to F.1 in annex F of Is0 8096-3:1988) has been developed in more detail and is now widely available commercially from a number of sources. Flex testing can provide a useful indication of the durability of coated fab- test methods are dissimilar to the conditions met in practice. In particular, the micro-climate induced around the test piece and the thermal stresses induced in the molecular structure of the coating during flexing are unlikely to be representative of practical situations. It is important therefore that these effects be kept to a minimum and their effect be given due con- sideration when test results are being considered. Consequently, it is im- portant to ensure that the air temperature a