ISO INTERNATIONAL STANDARD 13760 First edition 1998-05-15 Plastics pipes for the conveyance of fluids under pressure Miner's rule Calculation method for cumulative damage Tubes en matieres plastiques pour le transport des fluides sous pression - Regle de Miner - Meéthode de calcul du cumul des dommages ISO Referencenumber ISO13760:1998(E) y IHS under itted without license from IHS Not for Resale ISO13760:1998(E) Foreword ISO (the International Organization for Standardization) is a worldwide preparing International Standards is normally carried out through IsO technical committees. Each member body interested in a subject for which atechnicalcommitteehasbeenestablishedhastherighttoberepresented 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 Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard iSO 13760 was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the transport of fluids, Subcommittee Sc 5, General properties of pipes, fittings and valves of plastic materials and their accessories - Test methods and basic specifications. @ISO1998 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. InternationalOrganizationforStandardization Casepostale56·CH-1211Geneve20·Switzerland Internet [email protected] Printed in Switzerland it license from IHS Not for Resale INTERNATIONAL STANDARD @ ISO ISO 13760:1998(E) Plastics pipes for the conveyance of fluids under pressure - Miner's rule Calculation method for cumulative damage Scope This International Standard specifies a method for calculating the maximum allowable hoop stress applicable to pipes exposed to varying internal pressures and/or temperatures during their expected lifetime. This method is generally known as Miner's rule. It is necessary to apply Miner's rule to each failure mechanism separately. Thus, for mechanical failure due to internal pressure, other failure mechanisms, such as oxidative or dehydrochlorinative degradative failure mechanisms, are to be neglected (assuming, of course, no interaction). A material may be used only when it is proven to conform to all failure mechanism criteria. NOTE - Miner's rule is an empirically based procedure, and is only a first approximation to reality. 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and IsO maintain registers of currently valid International Standards. IsO 10508:1995, Thermoplastics pipes and fittings for hot and cold water systems. 3 Symbols and abbreviated terms For the purposes of this International Standard, the following symbols and abbreviations apply: ai fraction of a year, expressed as a percentage, when referring to set of conditions ""; ti lifetime under a specified set of conditions "j" (i= 1, 2, 3, etc.) expressed in years; tm lifetime at malfunction temperature Tm as defined in ISO 10508; tmax lifetime at maximum operating temperature Tmax as defined in ISO 10508; to lifetime at operating temperature To as defined in ISO 10508; tx maximum permissible time of use under varying conditions, expressed in years; TYD total yearly damage, expressed as a percentage. onal Organization for Standardization Not for Resale