ISO 7432:2018

INTERNATIONAL ISO
STANDARD 7432
Second edition
2018-09
Glass-reinforced thermosetting
plastics (GRP) pipes and fittings —
Test methods to prove the design
of locked socket-and-spigot joints,
including double-socket joints, with
elastomeric seals
Tubes et raccords en plastiques thermodurcissables renforcés de
verre (PRV) — Méthodes d'essai pour confirmer la conception des
assemblages mâle-femelle verrouillés, y compris ceux à double
emboîture avec joints d'étanchéité en élastomère
Reference number
ISO 7432:2018(E)
©
ISO 2018

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ISO 7432:2018(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2018
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Published in Switzerland
ii © ISO 2018 – All rights reserved

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ISO 7432:2018(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 3
5.1 End-sealing devices. 3
5.2 Supports . 3
5.3 Source of hydrostatic pressure . 6
5.4 Pressure gauges. 6
5.5 Vacuum pump . 6
5.6 Means of applying and measuring the required deformation and bending forces . 6
6 Test pieces . 6
6.1 Assembly and test arrangement . 6
6.2 Number of test pieces . 6
7 Conditioning . 6
8 Test temperature . 7
9 Procedure. 7
9.1 General . 7
9.2 Negative pressure . 7
9.3 Deformation with internal pressure and end thrust . 7
9.4 Deformation with cyclic pressure and end thrust . 8
9.5 Bending with cyclic pressure and end thrust . 8
9.6 Internal pressure and end thrust . 8
10 Test report . 9
Annex A (normative) Calculation of the bending load F used in the bending test in 9.5 .11
2
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ISO 7432:2018(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.
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 drafted 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 rights. 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).
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URL: www .iso .org/iso/foreword .html.
This document 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 7432:2002), which has been technically
revised.
This edition includes the following significant changes compared to the previous edition:
— changed Scope to mention that the test procedure is a destructive test;
— terms and definitions clause added to this document;
— changed testing sequences from mandatory to recommended;
— changed wording from “misalignment” to “deformation”;
— modified test sequence for the proof of the design (Clause 9);
— changes in Table 1 with modified testing sequences for the proof of the design of joints;
— modification of bending test sequence.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
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ISO 7432:2018(E)

Introduction
In a pipework system, pipes and fittings of different nominal pressures and nominal stiffnesses may
be used.
A joint may be made between pipes and/or fittings and should be designed such that its performance
is equal to or better than the requirements for the pipeline, but not necessarily for the components
being joined.
The requirements for the assembly of the joint are not included in this document, but they should be in
accordance with the manufacturer’s recommendations.
The material-dependent parameters and/or performance requirements are stated in the referring
standard.
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INTERNATIONAL STANDARD ISO 7432:2018(E)
Glass-reinforced thermosetting plastics (GRP) pipes and
fittings — Test methods to prove the design of locked
socket-and-spigot joints, including double-socket joints,
with elastomeric seals
1 Scope
This document specifies methods of test for joints with a locked socket and spigot, including double-
socket joints, and with elastomeric seals, for buried and above ground glass-reinforced thermosetting
plastics (GRP) piping systems. It covers methods of test for leaktightness and resistance to damage of the
joint only, when subjected to specified combinations of angular movement, compression (deformation)
perpendicular to the pipe axis and internal pressure. It assumes that the joint will be exposed to the
effects of hydrostatic end thrust.
This document is applicable to joints for either pressure or non-pressure applications. The tests are
suitable for the evaluation of joints intended for applications in which the liquids are conveyed at
temperatures specified in the referring standards.
The joints tested in accordance with this document are subjected to conditions which measure their
ability to function and thereby prove the design of the joint, especially for type test purposes. The joint
is only qualified according to the test sequences and configurations detailed in this document.
With the exception of the bending test (see 9.5), the test procedures are applicable to joints for pipes
and fittings of all nominal sizes. If not otherwise agreed between the manufacturer and the customer,
the bending test detailed in 9.5 is applicable to joints with pipes and fittings up to and including DN 600.
The test procedures in this document are damaging to the test piece, which will not be suitable for
reuse after these tests. The test procedure is intended to be applied for type testing purposes.
This document is applicable only to the joint and specifies methods of test to prove its design.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http: //www .electropedia .org/
— ISO Online browsing platform: available at http: //www .iso .org/obp
3.1
pressure
hydrostatic gauge pressure
Note 1 to entry: Expressed in bar.
3.2
bending
bending in the pipe and coupling configuration as a result of a vertical force on the coupling
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ISO 7432:2018(E)

3.3
deformation
pipe deformation in the coupling as a result of a vertical force on the pipe and a supported coupling
causing a step between the two pipe spigots at the loading position
4 Principle
A test piece comprising two pieces of pipe jointed together, by incorporation of a socket or inclusion of a
double-socket coupler, is subjected to specified load conditions, including combinations of bending and
deformation. In each specified combination the test piece is subjected to a series of test pressures for
specified periods of time, including an internal sub-atmospheric test pressure. This also simulates an
external positive pressure.
In addition, a test at elevated positive static pressure is conducted to prove the structural design of the
coupling (see Table 1 and 9.6).
In the tests detailed in 9.5 the joint is subjected to a bending load of such a magnitude that the axial
tensile stress in the pipe is equal to that developed from a pressure of 0,5 times PN [see Formula (1)].
01,[PN](×+de)
i
σ =05, (1)
b
4e
In addition, the joint is then pressure tested at 1,5 times PN, which then results in a total axial stress
(bending plus pressure), σ , equivalent to 2 times PN, i.e.:
ax
01,[PN]×d
i
σ = (2)
ax
2e
When under pressure, the joint is monitored for leakage. After each test condition (see Table 1) the joint
is inspected for signs of damage.
NOTE 1 The only reason for testing the joint for resistance to negative pressure is to ensure adequate safety
against infiltration of pollutants through the joint into the fluid carried in the piping system. Under the test
conditions used, pipes with low stiffness can require support to prevent buckling.
NOTE 2 If not otherwise specified, the ISO product standards ISO 10639, ISO 10467 and ISO 25780 specify the
following test parameter. It is assumed these test parameters are also set by other applicable product standards.
If this is not the case the parameters detailed in this document and in ISO 10639, ISO 10467 as well as ISO 25780
can be used as default values.
NOTE 3 It is assumed that the following test parameters are set by the standard making reference to this
document:
— the nominal size of the components to be connected by the joint (see 6.1);
— the pressure class of the components (see 6.1);
— the total effective length, L, of the test piece (see 6.1);
— the number of test pieces (see 6.2);
— if applicable, the conditioning to be applied (see Clause 7);
— the test temperature (see Clause 8);
— the sequence of testing, if appropriate (see 9.1);
— the test configuration (see Table 1);
— the deformation and bending forces F and F (see 9.3, 9.4, 9.5, and 9.6);
1 2
— the permissible change in negative pressure (see 9.2.3).
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ISO 7432:2018(E)

5 Apparatus
5.1 End-sealing devices
The end sealing devices shall be of sizes and type appropriate to the components under test. The end-
sealing devices shall be securely fixed to the pipes to transmit the end thrust loads to the pipes.
5.2 Supports
5.2.1 Straps or cradles, for use as follows:
a) a support R (item 6 in Figure 2) positioned at least 500 mm from the spigot end of the pipe at the
point of balance to provide support during testing with deformation (see 9.3 and 9.4);
b) a strap or cradle (100 ± 5) mm wide (item 7 in Figure 2) supporting at least a 120° arc of the
socket, as required for deformation testing (see 9.3 and 9.4);
c) a strap or cradle (100 ± 5) mm wide supporting an arc up to 180° of the pipe barrel, positioned
adjacent to the end of the joint being tested (item 5 in Figure 2) and through which the force F
1
necessary for deformation testing (see 9.3 and 9.4) can be applied;
d) a strap or cradle (100 ± 5) mm wide supporting an arc up to 180° of the pipe barrel, positioned in
the middle of the joint being tested (item 5 in Figure 3) and through which the force F necessary
2
for the bending test (see 9.5) can be applied;
e) supports of sufficient width to carry the pipe components of the test piece (item 3 in Figure 2) and
designed in such a way that they allow
...