ISO 7432:2021

INTERNATIONAL ISO
STANDARD 7432
Third edition
2021-04
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 2021
© ISO 2021
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ii © ISO 2021 – All rights reserved

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 . 3
5.4 Pressure gauges. 3
5.5 Vacuum pump . 3
5.6 Means of applying and measuring the required deformation and bending forces . 3
6 Test pieces . 4
6.1 General . 4
6.2 Test arrangement for tests detailed in 9.2 and 9.6 . 4
6.3 Test arrangement for tests detailed in 9.3 and 9.4 . 4
6.4 Test arrangement for tests detailed in 9.5 . 5
6.5 Number of test pieces . 7
7 Conditioning . 7
8 Test temperature . 7
9 Procedure. 7
9.1 General . 7
9.2 Negative pressure . 8
9.3 Deformation with internal pressure and end thrust . 9
9.4 Deformation with cyclic pressure and end thrust . 9
9.5 Bending with cyclic pressure and end thrust . 9
9.5.1 Introductory notes . 9
9.5.2 Method A .10
9.5.3 Method B .10
9.6 Internal pressure and end thrust .11
10 Test report .11
Annex A (normative) Calculation of the additional force, F , and limiting deflection, Δ, used
A
in 9.5, Method A .13
Annex B (normative) Calculation of the bending load, F , used in the bending test in 9.5,
B
Method B .14
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
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electrotechnical standardization.
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different types of ISO documents should be noted. This document was drafted in accordance with the
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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 third edition cancels and replaces the second edition (ISO 7432:2018), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— addition of the bending test (Method A), which was already included in ISO 7432:2002.
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.
iv © ISO 2021 – All rights reserved

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.
Material-dependent parameters and/or performance requirements are stated in the relevant standard.
INTERNATIONAL STANDARD ISO 7432:2021(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 testing 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.
The tests detailed in 9.2, 9.3, 9.4 and 9.6 are applicable to joints with a locked socket and spigot,
including double-socket joints, and with elastomeric seals intended to be used in buried or above-
ground applications.
The bending tests detailed in 9.5 can be used to prove the design where joints are either intended to be
used in buried applications or are intended to be used in particular above-ground situations, where the
tests can be considered appropriate.
With the exception of the procedure detailed in 9.5, these test procedures are applicable to joints
for pipes and fittings of all nominal sizes. The tests detailed in 9.5 are applicable to joints for pipes
and fittings up to and including DN 600. The tests are applicable for evaluating joints intended for
applications conveying liquids at temperatures specified in the referring standards.
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 for type testing purposes.
This document is applicable only to the joint and specifies methods of testing 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:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
pressure
hydrostatic gauge pressure
Note 1 to entry: Expressed in bar.
3.2
bending
beam bending in the pipe and joint configuration as a result of a transverse force on the joint
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 press
...