ISO 10952:2008

INTERNATIONAL ISO
STANDARD 10952
Second edition
2008-10-15

Plastics piping systems — Glass-
reinforced thermosetting plastics (GRP)
pipes and fittings — Determination of the
resistance to chemical attack for the
inside of a section in a deflected
condition
Systèmes de canalisations en matières plastiques — Tubes et raccords
en plastiques thermodurcissables renforcés de verre (PRV) —
Détermination de la résistance à une attaque chimique à l'intérieur d'un
tronçon de tube soumis à déflexion




Reference number
ISO 10952:2008(E)
©
ISO 2008

---------------------- Page: 1 ----------------------
ISO 10952:2008(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.


COPYRIGHT PROTECTED DOCUMENT


©  ISO 2008
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 either ISO at the address below or
ISO's 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 copyright@iso.org
Web www.iso.org
Published in Switzerland

ii © ISO 2008 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 10952:2008(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 which a technical committee 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 electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. 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.
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.
ISO 10952 was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the
transport of fluids, Subcommittee SC 6, Reinforced plastics pipes and fittings for all applications.
This second edition cancels and replaces the first edition (ISO 10952:1999), of which it constitutes a technical
revision.
© ISO 2008 – All rights reserved iii

---------------------- Page: 3 ----------------------
INTERNATIONAL STANDARD ISO 10952:2008(E)

Plastics piping systems — Glass-reinforced thermosetting
plastics (GRP) pipes and fittings — Determination of the
resistance to chemical attack for the inside of a section in a
deflected condition
1 Scope
This International Standard specifies a method for determining the chemical resistance properties of glass-
reinforced thermosetting plastics (GRP) pipes and fittings in a deflected condition for nominal sizes DN 100
and larger.
In conjunction with ISO 10928, this International Standard provides a method for evaluating the effect of a
chemical environment on the interior of a pipe or fitting after a specified period of time. Test conditions and
requirements are specified in the referring standards such as ISO 10467.
NOTE It has been found that the effect of chemical environments can be accelerated by strain induced from
deflection; hence, it is frequently referred to as strain corrosion.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
1)
ISO 10928:— , Plastics piping systems — Glass-reinforced thermosetting plastics (GRP) pipes and fittings —
Methods for regression analysis and their use
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
mean diameter
d
m
diameter of the circle corresponding with the middle of the pipe wall cross section
NOTE 1 The mean diameter is given by either of the following equations:
d = d + e
m i m
d = d − e
m e m

1) To be published. (Revision of ISO 10928:1997)
© ISO 2008 – All rights reserved 1

---------------------- Page: 4 ----------------------
ISO 10952:2008(E)
where
d is the external diameter of the pipe;
e
d is the internal diameter of the pipe;
i
e is the mean wall thickness of the pipe at the bottom.
m
NOTE 2 The mean diameter and the dimensions used to calculate it are expressed in millimetres.
3.2
leak failure
failure which becomes apparent by the passage of the test liquid through the pipe wall
4 Principle
The interior of a test piece is exposed to a corrosive test liquid at a specified temperature while being
maintained in a fixed diametrically deflected condition. The test is repeated at several deflection levels, using
a fresh test piece each time and recording the time to leak failure at each deflection. The results are used to
calculate an extrapolated deflection value for a specified period of time.
Alternatively the extrapolation can be performed using calculated or measured strains. Strain can be
measured using strain gauges.
NOTE Use of strain allows testing using test pieces of variable thickness and stiffness classes. Deflection and strain
are interrelatable by calculation.
It is assumed that the following test parameters are set by the standard making reference to this International
Standard:
a) the composition of the test liquid (see Clause 5);
b) the number and length of test pieces (see Clause 7);
c) the pre-conditioning to be applied (see Clause 9);
d) the test temperature (see 10.1 or 11.1);
e) if failures do not occur (see 10.11 and 11.11), the specified deflection levels and related minimum time
intervals;
f) the time to which the data have to be extrapolated (see Clause 12).
5 Test liquid
The test liquid shall be as specified in the referring standard. The quantity shall be sufficient to achieve and
maintain for the duration of the test the specified depth within the test piece (see 10.7 or 11.7).
6 Apparatus
6.1 Loading frame, comprising two parallel steel sections and threaded rods which can maintain a
constant deflection of the test piece (see Figure 1). The sections shall be sufficiently stiff such that visible
bending or deformation of the sections does not occur during the compression of the test piece. Each section
shall have a length equal to the length of the test piece plus at least 30 mm and a width of at least 100 mm.
2 © ISO 2008 – All rights reserved

---------------------- Page: 5 ----------------------
ISO 10952:2008(E)
6.2 Dimensional measuring devices, capable of determining:
a) the dimensions (length, diameter, wall thickness) to an accuracy of within ± 0,5 %;
b) the change in diameter of the test piece in the vertical direction to an accuracy of within ± 1,0 % of the
maximum value of the change;
c) if used, strain gauges of the foil type, single element suitable for the maximum anticipated strain level and
a length appropriate for the pipe diameter.
Strain gauges of length 6 mm and 12 mm have been found to be effective for pipe diameters 300 mm to
600 mm. Consult the strain gauge manufacturer for gauge length recommendations for other pipe diameters.

Key
1 steel channel section
2 dam
3 sealant
4 threaded rod
5 test liquid
6 test piece
7 strain gauge (optional)
D deflected diameter
dm
Figure 1 — Typical test set-up
7 Test pieces
7.1 Preparation
The test piece shall comprise a complete ring cut from the pipe or fitting to be tested. The length of the test
piece shall be as specified in the referring standard, with permitted deviations of ± 5 %.
The cut ends shall be smooth and perpendicular to the axis of the test piece.
Two straight lines, diametrically opposed, shall be drawn longitudinally on the inside of the test piece.
© ISO 2008 – All rights reserved 3

---------------------- Page: 6 ----------------------
ISO 10952:2008(E)
7.2 Number
The number of test pieces shall be as specified in the referring standard, provided that for regression analysis
the number of test pieces is such that a minimum of 18 data points in accordance with 10.2 or 11.2 can be
obtained.
8 Determination of the dimensions of the test piece
8.1 Length
Measure the length of the test piece along each line with sufficient accuracy to determine whether or not each
test piece conforms with the requirements of Clause 7. Trim or replace, as applicable, each test piece that
does not conform.
8.2 Mean wall thickness
Measure (6.2), to an accuracy of within ± 1,0 %, the wall thickness of the test piece at six equally spaced
locations along one of the longitudinal lines specified in 7.1. (This line then becomes the bottom of the test
piece.) Calculate the mean wall thickness, e , as the arithmetic average of the six measured values.
m
8.3 Mean diameter
Measure (6.2), to an accuracy of within ± 1,0 %, either the internal diameter, d , of the test piece at mid-length,
i
by means of e.g. a calliper, or the external diameter, d , of the test piece, by means of e.g. a circumferential
e
wrap steel tape.
Determine the mean diameter, d (see 3.1), of the test piece by calculation using the values obtained for
m
mean wall thickness, e , and either the internal or the external diameter.
m
9 Conditioning
Unless otherwise specified by the referring standard, the test pieces shall be stored under testing conditions
for at least 8 h.
10 Test procedure using deflection measurement
WARNING — Contain any fragmentation or leakage that can occur during the test.
10.1 During the following procedure, maintain the temperature specified in the referring standard.
10.2 Select the range of estimated deflections such that the times to failure of at least 18 test pieces are
distributed between 0,1 h and over 10 000 h, and the distribution of failure times of at least 10 values
conforms to the limits given in Table 1.
NOTE Deflections in excess of 28 % of diameter can cause local flattening of the pipe and lead to erratic strain
distribution. For deflections approaching 28 % improved accuracy is obtained by use of additional strain gauges or by
establishing, for a typical test piece, a calibration of defle
...