1、BSI Standards Publication BS ISO 7509:2015 Plastics piping systems Glass-reinforced thermosetting plastics (GRP) pipes Determination of time to failure under sustained internal pressureBS ISO 7509:2015 BRITISH STANDARD National foreword This British Standard is the UK implementation of ISO 7509:2015
2、. The UK participation in its preparation was entrusted to Technical Committee PRI/88/2, Plastics piping for pressure applications. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provis
3、ions of a contract. Users are responsible for its correct application. The British Standards Institution 2015. Published by BSI Standards Limited 2015 ISBN 978 0 580 80914 9 ICS 23.040.20 Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was publ
4、ished under the authority of the Standards Policy and Strategy Committee on 31 March 2015. Amendments issued since publication Date Text affectedBS ISO 7509:2015 ISO 2015 Plastics piping systems Glass- reinforced thermosetting plastics (GRP) pipes Determination of time to failure under sustained int
5、ernal pressure Systmes de canalisations en plastiques Tubes en plastiques thermodurcissables renforcs de verre (PRV) Dtermination du temps mis jusqu la dfaillance sous une pression interne constante INTERNATIONAL STANDARD ISO 7509 Second edition 2015-03-01 Reference number ISO 7509:2015(E)BS ISO 750
6、9:2015ISO 7509:2015(E)ii ISO 2015 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2015 All 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 o
7、n the internet or an intranet, without 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 office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrighti
8、so.org Web www.iso.org Published in SwitzerlandBS ISO 7509:2015ISO 7509:2015(E)Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 T erms and definitions . 1 4 Principle 2 5 Apparatus . 2 6 Test pieces . 4 6.1 Number 4 6.2 Free length 4 6.3 Cutting 4 7 Conditioning 4 8 Procedure. 4 9 D
9、etection of failure 5 9.1 General . 5 9.2 Detection methods . 5 9.2.1 Loss of test liquid . 5 9.2.2 Drop in electrical resistance 6 10 Test report . 6 Annex A (informative) Electronic leak/weep detection . 7 ISO 2015 All rights reserved iii Contents PageBS ISO 7509:2015ISO 7509:2015(E) Foreword ISO
10、(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 comm
11、ittee 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 electrote
12、chnical standardization. The procedures used to develop this document 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 draft
13、ed in accordance with the editorial rules of the ISO/IEC Directives, 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 rig
14、hts. Details of any patent rights identified during the development 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 consti
15、tute an endorsement. For an explanation on the meaning of ISO specific 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 co
16、mmittee responsible for this document is ISO/TC 138, Plastics pipes, 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 technicall
17、y revised.iv ISO 2015 All rights reservedBS ISO 7509:2015ISO 7509:2015(E) Introduction This 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 conditio
18、ns: water as the reference liquid inside the test piece; water or air, as 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
19、whether the external environment is water or air. The method described in this 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 m
20、easured during the test; the test pressure is maintained constant. This method 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 St
21、andard. For such purposes, attention is drawn to ISO 10928. ISO 2015 All rights reserved vBS ISO 7509:2015BS ISO 7509:2015Plastics piping systems Glass-reinforced thermosetting plastics (GRP) pipes Determination of time to failure under sustained internal pressure 1 Scope This International Standard
22、 specifies a method for determining the time-to-failure of glass-reinforced thermosetting 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
23、specify any additional requirement. 2 Normative references The following documents, 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 refe
24、renced document (including any amendments) applies. ISO 3126, Plastics piping systems Plastics components Determination of dimensions ISO 10928, Plastics piping systems Glass-reinforced thermosetting plastics (GRP) pipes and fittings Methods for regression analysis and their use 3 T erms a nd defini
25、ti ons For the purposes of this document, the following terms and definitions apply. 3.1 failure occurrence of bursting, leaking, or weeping Note 1 to entry: See 9.1. 3.2 bursting failure by rupture of the pipe wall with immediate loss of test liquid and drop of pressure Note 1 to entry: See 9.1 and
26、 9.2.1. 3.3 leaking failure by visible loss of the pressurizing liquid through the pipe wall to an extent detectable visually and/or by a continuous drop in pressure Note 1 to entry: See 9.1 and 9.2.1 3.4 weeping failure by passage of the pressurizing liquid through the pipe wall to an extent detect
27、able visually and/or electronically Note 1 to entry: See 9.1 and 9.2.2. INTERNATIONAL ST ANDARD ISO 7509:2015(E) ISO 2015 All rights reserved 1BS ISO 7509:2015ISO 7509:2015(E) 4 Principle A cut length of pipe at the required temperature is subjected to a specified internal hydrostatic pressure to ca
28、use a state of stress in the pipe wall, which depends upon the loading conditions (i.e. with or without the 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 enviro
29、nment outside of the test piece. The test samples are held at the test pressure until failure occurs. Typically, 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 wit
30、h ISO 10928 to establish a long term value. The number of tests required, the appropriate time intervals, and 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
31、 to this International Standard: a) whether or not the test piece is to be loaded by the hydrostatic end thrust 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 measu
32、rements are required (see 8.2); f) external environmental fluid, i.e. water or air (see 8.3) or other environment (see 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 Apparatus 5.1 Dimensional measurement d
33、evices, for determining length, diameter, and wall thickness with an accuracy of within 1,0 %. 5.2 End sealing devices, for 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 on
34、ly typical and other configurations are possible.2 ISO 2015 All rights reservedBS ISO 7509:2015ISO 7509:2015(E) Key 1 valid failure zone 2 end fixture influence zone, equal to e 3 end cap 4 test specimen 5 tie rod to carry end thrust 6 elastomeric seal 7 end seal device e wall thickness L free lengt
35、h between end fixtures Type 1 testing with end thrust Type 2 testing without end thrust, external seals Type 3 testing without end thrust, internal seals Figure 1 Typical arrangements for pressure testing of pipes 5.3 Test piece support(s), as necessary to minimize deformation of the test piece due
36、to its own weight. Such support(s) shall not constrain the test piece circumferentially or longitudinally. 5.4 Container for water, 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
37、require circulation. ISO 2015 All rights reserved 3BS ISO 7509:2015ISO 7509:2015(E) 5.5 Pressurizing system, capable of applying the 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 detaile
38、d in 8.5 for the duration of the test. The pressure should, preferably, be applied individually to each test piece. However, the use 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
39、the tests are carried out at a specified stress, the dimensions of the various test pieces should be similar. It is recommended that 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 te
40、st pressure. 5.7 Electrical resistance meter and associated circuit (optional, see 9.1), capable of detecting a change in electrical resistance 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.
41、3), capable of measuring the required strain to an accuracy of within 2 %. 6 Test pieces 6.1 Number The number of test pieces shall be as specified in the referring standard. 6.2 Free length Each test piece shall comprise of a full section of the pipe, the free length ( L) which, between the sealing
42、 devices, shall be as specified in the referring standard. 6.3 Cutting The ends shall be smooth and perpendicular to the axis of the pipe. 7 Conditioning Unless 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 Proce
43、dure 8.1 Conduct the following procedures at the temperature and tolerance specified in the referring standard. 8.2 In accordance with ISO 3126, measure the pipe diameter, wall thickness, and test sample length. 8.3 If strain measurements are required, attach strain gauges and use equipment conformi
44、ng 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 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 te
45、sting 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 pressure 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
46、 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 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
47、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 the total running time of the test and shall be noted in the test report. 9 Detection of failure 9.1 General The test piece shall be considered
48、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 9.2.1). Weeping can be detected visually or physically by measuring the electrical resistance (see 9.2.2). NOTE Weeping can be determined only
49、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 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
