ISO INTERNATIONAL STANDARD 3127 Second edition 1994-12-01 Thermoplastics pipes - Determination of resistance to external blows - Round-the-clock method Tubes en matieres thermoplastiques Determination de la résistance aux chocs extérieursMéthode autourdu cadran ISO Reference number ISO 3127:1994(E) Copyright Ilr No reproduction or networking permited without license from IHS Not for Resale ISO 3127:1994(E) Foreword IsO (the International Organization for Standardization) is a worldwide technical committees. Each member body interested in a subject for which atechnical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with IsO, aiso 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. IsO/TC 138, Plastics pipes, fittings and valves for the transport of fluids Subcommittee SC 5, General properties. This second edition cancels and replaces the first edition (ISO 3127:1980), whichhasbeentechnicallyrevised. Annexes A and B of this International Standard are for information only. ISO 1994 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 No reproduction or networking permited without icense from IHS Not fr Resale ISO 3127:1994(E) INTERNATIONAL STANDARD ISO Thermoplastics pipes --- Determination of resistance to external blows -- Round-the-clock method 1 Scope circumference of the test piece. The true impact rate (TIR) of the batch, or production run from an extruder, This International Standard specifies a method for the is estimated. determinationoftheresistancetoexternalblows of thermoplastics pipes of circular cross-section; it is The severity of this test method can be adjusted by calledthe round-the-clock method. changing the mass of the striker and/or by changing the drop height. It is not technically correct to vary the This method is applicable to isolated batches of pipe severity of the test by choosing values of the TiR tested at o c (information is also given for sampling other than those specified below. from the continuous production of pipe). The maximum value acceptable for the TiR is taken to NOTE 1 If testing below 0 'C is required, a temperature of be 10 %. - 20 °c is recommended. NOTE 3 It should be appreciated that a completely definitive result can be reached only by testing the whole 2 Definitions batch, but in practice a balance is necessary between the statisticai possibility of a definitive result and the cost of For the purposes of this International Standard, the further testing. foilowing definitions apply. 2.1 true impact rate (TIR): The total number of 4 Apparatus failuresdividedbythetotalnumberofblows,as a percentage, as if the whole batch had been tested. 4.1 Falling-weight testing machine, incorporating the following basic components (see figure 1). NOTE 2 In practice, test pieces are drawn at random from the batch and the result is only an estimate of the TIR for that batch. 4.1.1 Main frame, with guide rails or a guiding tube rigidlyfixedintheverticalposition,to accommodatea 2.2 failure: Unless otherwise specified in the striker(4.1.2)andreleaseittofallverticallyandfreely product standard, shattering or any crack or split on When calibrated, the speed of the striker at the the inside of the pipe that was caused by the impact moment of impact shall be n