ISO 10952:1999

INTERNATIONAL IS0
STANDARD 10952
First edition
1999-07-l 5
Plastics piping systems - Glass-reinforced
thermosetting plastics (GRP) pipes and
fittings - Determination of the resistance
to chemical attack from the inside
of a section in a deflected condition
Systkmes de canalisations en mat&es plastiques - Tubes et raccords en
plastiques thermodurcissables renforck de verre (PR V) - D6 termina tion
de la r&istance B une attaque chimique par I’intkieur d’un tronqon de tube
soumis 5 dgflexion
Reference number
IS0 10952: 1999(E)

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ISO 10952:1999(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0
member bodies). The work of preparing International Standards is normally carried out through IS0 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. IS0 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.
International Standard IS0 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, in
collaboration with CEN/TC 155, Plastics piping systems and ducting systems.
This standard is one of a series of standards on test methods which support standards for plastics piping systems
and ducting systems.
0 IS0 1999
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 l CH-1211 Geneve 20 l Switzerland
Internet iso @ iso.ch
Printed in Switzerland
ii

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INTERNATIONAL STANDARD o IS0
IS0 10952: 1999(E)
Plastics piping systems - Glass-reinforced thermosetting plastics
Determination of the resistance to
(GRP) pipes and fittings -
chemical attack from the inside of a section in a deflected
condition
1 Scope
This 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 IS0 10928 this 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.
This method shall also be used as the basis for conducting tests according to so called “specified
levels” as allowed by referencing system standards. The specified level approach does not involve
extrapolation of test data.
NOTE I: It has been found that the effect of chemical environments can be accelerated using
strain induced by deflection, hence it is frequently referred to as strain corrosion.
2 Normative reference
The following standard contains provisions which, through reference in this text, constitute provisions of
this International Standard. At the time of publication, the edition indicated was valid. All standards are
subject to 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 IS0 maintain registers of currently valid International Standards.
For undated references the latest edition of the publication referred to applies.
IS0 10928;1997, Plastics piping systems - Glass-reinforced thermosetting plastics (GRP) pipes and
fittings - Methods for regression analysis and their use.
3 Definitions
For the purposes of this standard, the following definitions apply:
3.1 mean diameter (d,): The diameter of the circle corresponding with the middle of the pipe wall
cross section.
It is given, in millimetres, by either of the following equations:
d m = di + e
where:
di is the internal diameter, in millimetres;
de is the external diameter, in millimetres;
e is the wall thickness of the pipe, in millimetres.

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0 IS0
IS0 10952:1999(E)
3.2 leak failure: Failure which becomes apparent by the passage of the test liquid through the pipe
wail.
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 by the use of strain gauges.
NOTE I: Use of strain allows fesfing using fesf pieces of variable fhickness and stiffness
classes. Deflection and strain are inferrelafable by calculafion.
NOTE 2: If is assumed that the following fesf parameters are set by the standard making
reference to this standard:
a) the composition of the test liquid (see clause 5);
b) the number and length of test pieces (see clause 7);
c) if applicable, the preconditioning to be applied (see clause 9);
d) the test temperature (see 10.1 or 11-l);
e) if failures do not occur (see 10.11 or 11.11) the specified deflection levels and related
minimum time intervals;
9 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
the specified depth within the test piece (see 10.7 or 11.7).
6 Apparatus
6.1 Loading frame, comprising two parallel steel sections, with or without bearing plates, and
threaded rods which can maintain a constant deflection of the test piece (see figure 1). The surfaces in
contact with the test piece shall be hard, flat, smooth and clean. The sections and bearing plates shall
be sufficiently stiff such that visible bending or deformation of the sections or plate does not occur
during the compression of the test piece. Each section or plate shall have a length at least equal to the
length of the test piece plus 30 mm and a width of at least 100 mm.
2

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0 IS0 IS0 10952: 1999(E)
Dimensions in miilimetres
kp
.
.
&
A
=I=
- a-
?
-?
A-A B-B
Key
1 Threaded rod 5 Test liquid
2 Steel section 6 Sealant
7
3 Test piece Strain gauge(s)
4 Dam 8 Bearing plate (optional)
Figure 1 - Typical test arrangement
3

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0 IS0
IS0 10952:1999(E)
6.2 Dimensional measurement devices, capable of determining:
- the dimensions (length, diameter, wall thickness) to an accuracy of within 2 0,s %;
direction to an accuracy of within & 1,O %
- the change in diameter of the test piece in the vertica
of the maximum value of the change.
for strain levels up to 1,5 % strain and a
6.3 Strain gauges of the foil type, single element suitable
length appropriate for the pipe diameter.
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 k 5 %.
The cut ends shall be smooth and perpendicular to the axis of the pipe or fitting.
Two straight lines, diametrically opposed, shall be drawn longitudinally on the inside of the test piece.
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 (see clause 7) with sufficient accuracy to
determine whether or not each test piece conforms to clause 7. Trim or replace, as applicable, each
test piece that does not conform.
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0 IS0
IS0 10952: 1999(E)
8.2 Mean wall thickness
Measure to within & 1 ,O % the wall thickness of the test piece at each end of the test piece at three
positions equally distributed around the circumference. Calculate the mean wall thickness, e, as the
average of the six measured values.
8.3 Mean diameter
Measure to an accuracy of within & 1,O % either the internal diameter, di, of the test piece at mid-
length, by means of e.g. a calliper, or the external diameter, d,, of the test piece, by means of e.g. a
circumferential wrap steel tape.
Determine the mean diameter, d,, of the test piece by calculation using the values obtained for mean
wall thickness and either the internal or the external diameter (see 3.1).
9 Conditioning
Unless otherwise specified by the referring standard, the test pieces shall not be conditioned.
IO Test procedure using deflection measurement
WARNING: Precautions should be taken to 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,l h and over 10000 h and the distribution of failure times of at least
10 values conforms to the limits given in table 1.
Table 1: Failure time distribution
Failure time Minimum number
h of failures
2 10 and 5 1000 4
> 1000 and < 6000
3
*
> 6000 3
>
*) At least one of these shall exceed 10000 h
NOTE: Deflections in excess of 28 % of diam
...