1、BSI Standards PublicationBS ISO 7509:2015Plastics piping systems Glass-reinforced thermosettingplastics (GRP) pipes Determination of time tofailure under sustained internalpressureBS ISO 7509:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 7509:2015.The UK
2、 participation in its preparation was entrusted to TechnicalCommittee PRI/88/2, Plastics piping for pressure applications.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a con
3、tract. Users are responsible for its correctapplication. The British Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 80914 9ICS 23.040.20Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the auth
4、ority of theStandards Policy and Strategy Committee on 31 March 2015.Amendments issued since publicationDate Text affectedBS ISO 7509:2015 ISO 2015Plastics piping systems Glass-reinforced thermosetting plastics (GRP) pipes Determination of time to failure under sustained internal pressureSystmes de
5、canalisations en plastiques Tubes en plastiques thermodurcissables renforcs de verre (PRV) Dtermination du temps mis jusqu la dfaillance sous une pression interne constanteINTERNATIONAL STANDARDISO7509Second edition2015-03-01Reference numberISO 7509:2015(E)BS ISO 7509:2015ISO 7509:2015(E)ii ISO 2015
6、 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015All rights reserved. Unless otherwise specified, 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, with
7、out prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in Switze
8、rlandBS ISO 7509:2015ISO 7509:2015(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 25 Apparatus . 26 Test pieces . 46.1 Number 46.2 Free length 46.3 Cutting 47 Conditioning 48 Procedure. 49 Detection of failure 59.1 General . 59.2 Detection method
9、s . 59.2.1 Loss of test liquid . 59.2.2 Drop in electrical resistance 610 Test report . 6Annex A (informative) Electronic leak/weep detection . 7 ISO 2015 All rights reserved iiiContents PageBS ISO 7509:2015ISO 7509:2015(E)ForewordISO (the International Organization for Standardization) is a worldwi
10、de 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 tha
11、t 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 docum
12、ent 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 Directive
13、s, 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
14、 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 meaning of ISO specifi
15、c terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT), see the following URL: Foreword Supplementary information .The committee responsible for this document is ISO/TC 138, Plastics pipes,
16、fittings and valves for the transport of fluids, Subcommittee SC 06, Reinforced plastics pipes and fittings for all applications.This second edition cancels and replaces the first edition (ISO 7509:2000), which has been technically revised.iv ISO 2015 All rights reservedBS ISO 7509:2015ISO 7509:2015
17、(E)IntroductionThis International Standard describes a method for determining the long-term resistance to internal pressure of glass-reinforced thermosetting plastics (GRP) pipes.It is a method which uses the following conditions: water as the reference liquid inside the test piece; water or air, as
18、 the environment outside the test piece.The method can be used for tests at different temperatures. It should be noted that, for a given temperature, the results obtained can differ depending on the end loading conditions and whether the external environment is water or air.The method described in t
19、his International Standard differs from those in some other similar standards in the following details: the failure criteria and the detection of failure; the strain in the longitudinal and circumferential directions can be measured during the test; the test pressure is maintained constant.This meth
20、od can be used to obtain data to establish internal pressure versus time-to-failure relationships at different temperatures. The procedures for establishing the relationships are not within the scope of this International Standard. For such purposes, attention is drawn to ISO 10928. ISO 2015 All rig
21、hts reserved vBS ISO 7509:2015BS ISO 7509:2015Plastics piping systems Glass-reinforced thermosetting plastics (GRP) pipes Determination of time to failure under sustained internal pressure1 ScopeThis International Standard specifies a method for determining the time-to-failure of glass-reinforced th
22、ermosetting plastics (GRP) pipes under internal hydrostatic pressure at a specified temperature. The external environment can be air or water.NOTE For other internal or external environments, the referring standard is to specify any additional requirement.2 Normative referencesThe following document
23、s, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 3126, Plastics piping syst
24、ems Plastics components Determination of dimensionsISO 10928, Plastics piping systems Glass-reinforced thermosetting plastics (GRP) pipes and fittings Methods for regression analysis and their use3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1f
25、ailureoccurrence of bursting, leaking, or weepingNote 1 to entry: See 9.1.3.2burstingfailure by rupture of the pipe wall with immediate loss of test liquid and drop of pressureNote 1 to entry: See 9.1 and 9.2.1.3.3leakingfailure by visible loss of the pressurizing liquid through the pipe wall to an
26、extent detectable visually and/or by a continuous drop in pressureNote 1 to entry: See 9.1 and 9.2.13.4weepingfailure by passage of the pressurizing liquid through the pipe wall to an extent detectable visually and/or electronicallyNote 1 to entry: See 9.1 and 9.2.2.INTERNATIONAL STANDARD ISO 7509:2
27、015(E) ISO 2015 All rights reserved 1BS ISO 7509:2015ISO 7509:2015(E)4 PrincipleA cut length of pipe at the required temperature is subjected to a specified internal hydrostatic pressure to cause a state of stress in the pipe wall, which depends upon the loading conditions (i.e. with or without the
28、effects of end thrust being carried by the pipe wall). The results of tests at different end loading conditions will be different even for the same pipe. Water or air may be used as the environment outside of the test piece.The test samples are held at the test pressure until failure occurs. Typical
29、ly, the time to failure is longer at lower pressures (stresses).In general, a series of tests are conducted over various failure times and the results obtained are analysed in accordance with ISO 10928 to establish a long term value. The number of tests required, the appropriate time intervals, and
30、the time at which a value is established (time to failure) are given in the referring standard.NOTE It is assumed that the following test parameters are set by the standard making reference to this International Standard:a) whether or not the test piece is to be loaded by the hydrostatic end thrust
31、while under pressure (5.2);b) free length, L, of the test piece (see 6.2);c) number of test pieces (see 6.1);d) test temperature and its tolerance (see 8.1);e) if and what strain measurements are required (see 8.2);f) external environmental fluid, i.e. water or air (see 8.3) or other environment (se
32、e Note in Clause 1);g) internal environmental fluid, if not water or a test liquid for the purposes of 5.7 and 9.2.2 (see Note in Clause 1).5 Apparatus5.1 Dimensional measurement devices, for determining length, diameter, and wall thickness with an accuracy of within 1,0 %.5.2 End sealing devices, f
33、or the test piece, capable of inducing the specified state of stress, i.e. with or without hydrostatic end thrust (see Figure 1). The end sealing concepts shown in Figure 1 are only typical and other configurations are possible.2 ISO 2015 All rights reservedBS ISO 7509:2015ISO 7509:2015(E)Key1 valid
34、 failure zone2end fixture influence zone, equal to 3305,()DN e3 end cap4 test specimen5 tie rod to carry end thrust6 elastomeric seal7 end seal devicee wall thicknessL free length between end fixturesType 1 testing with end thrustType 2 testing without end thrust, external sealsType 3 testing withou
35、t end thrust, internal sealsFigure 1 Typical arrangements for pressure testing of pipes5.3 Test piece support(s), as necessary to minimize deformation of the test piece due to its own weight. Such support(s) shall not constrain the test piece circumferentially or longitudinally.5.4 Container for wat
36、er, if tested with water as the external environment (see 8.3), equipped so that the specified temperature can be maintained uniformly throughout the liquid.NOTE This can require circulation. ISO 2015 All rights reserved 3BS ISO 7509:2015ISO 7509:2015(E)5.5 Pressurizing system, capable of applying t
37、he pressure to the liquid in the test piece in such a way as to avoid entrapment of air. The system shall be capable of maintaining the pressure within the limits detailed in 8.5 for the duration of the test.The pressure should, preferably, be applied individually to each test piece. However, the us
38、e of equipment enabling the pressure to be applied simultaneously to several test pieces is also permitted if there is no danger of interference when failure occurs.If the tests are carried out at a specified stress, the dimensions of the various test pieces should be similar.It is recommended that
39、an automatic system be used which adjusts the pressure to keep it within the specified limits.5.6 Pressure measuring device, having an accuracy within 1,0 % of the test pressure.5.7 Electrical resistance meter and associated circuit (optional, see 9.1), capable of detecting a change in electrical re
40、sistance to a level of 3 M or less (see 9.2.2) between a sufficiently conductive test liquid and a conductive layer.5.8 Strain measuring device(s) (optional, see 8.3), capable of measuring the required strain to an accuracy of within 2 %.6 Test pieces6.1 NumberThe number of test pieces shall be as s
41、pecified in the referring standard.6.2 Free lengthEach test piece shall comprise of a full section of the pipe, the free length (L) which, between the sealing devices, shall be as specified in the referring standard.6.3 CuttingThe ends shall be smooth and perpendicular to the axis of the pipe.7 Cond
42、itioningUnless otherwise specified by the referring standard, store the test piece(s) at the test temperature (see 8.1) for 24 h prior to testing.8 Procedure8.1 Conduct the following procedures at the temperature and tolerance specified in the referring standard.8.2 In accordance with ISO 3126, meas
43、ure the pipe diameter, wall thickness, and test sample length.8.3 If strain measurements are required, attach strain gauges and use equipment conforming to 5.8.4 ISO 2015 All rights reservedBS ISO 7509:2015ISO 7509:2015(E)8.4 Attach the end-sealing devices (5.2) to the test piece (see Clause 6) and
44、fill the assembly completely with water or the test liquid (5.7). Attach the test piece to the pressurizing system, avoiding entrapment of air.If testing with water as the external environment, install the test piece in the container (5.4) so that it is totally surrounded with water.8.5 Raise the pr
45、essure inside the test piece to the desired level within 5 min (5.5). Maintain the pressure until failure. Record the test period to an accuracy of 2 % of the duration of the test period (in hours) or 24 h, whichever is the shorter.NOTE For some nominal sizes greater than DN 500, the duration of the
46、 test will, for practical reasons, need to be increased.8.6 In case of an interruption in testing due to unforeseen circumstances, such as power failure, the test may be continued if the duration of the interruption is less than 100 h. The length of the time of interruption(s) shall be deducted from
47、 the total running time of the test and shall be noted in the test report.9 Detection of failure9.1 GeneralThe test piece shall be considered to have failed when bursting (3.2), leaking (3.3), or weeping (3.4) is observed. Bursting or leaking can be detected visually or by loss of test liquid (see 9
48、.2.1). Weeping can be detected visually or physically by measuring the electrical resistance (see 9.2.2).NOTE Weeping can be determined only when the test is carried out in air.Because of the very high stresses (strains) generated by the extreme pressures used to develop short-term data points, the
49、discontinuity effects of the end closures can significantly influence the apparent times to failure. If the failure can be clearly identified as initiating from end fixture influence, the result of the test may be discarded if the failure occurs outside the valid failure zone, i.e. within a distance from an end sealing device, given in Formula (1):3305,()DN e (1)whereDN is the nominal size, expressed in millimetres;e is the wall thickness, in millimetres.Where feasible (i.e. where failure is by leaking or
