ISO 8639:2023

Glass-reinforced thermosetting plastics (GRP) pipes and fittings - Test methods for leaktightness and proof of structural design of flexible joints

This document specifies test methods for flexible non-thrust resistant socket-and-spigot joints with elastomeric sealing elements for buried and aboveground glass-reinforced thermosetting plastics (GRP) pipeline applications. It covers methods of test for the leaktightness and resistance to damage of the joint only, when subject to specified combinations of longitudinal extension (draw), angular movement (angular deflection), compression (deformation) perpendicular to the pipe axis and internal pressure. This document is applicable to joints for either pressure or non-pressure applications. NOTE 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. These test procedures are applicable to joints for pipes and fittings of all nominal sizes. 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 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.

Tubes et raccords en plastiques thermodurcissables renforcés de verre (PRV) — Méthodes d'essai pour l'étanchéité et preuve de conception structurelle de joint flexible

General Information

• Status: Published
• Publication Date: 24-Apr-2023
• ICS: 23.040.60 - Flanges, couplings and joints
• Technical Committee: ISO/TC 138/SC 6 - Reinforced plastics pipes and fittings for all applications
• Drafting Committee: ISO/TC 138/SC 6 - Reinforced plastics pipes and fittings for all applications
• Current Stage: 6060 - International Standard published
• Start Date: 25-Apr-2023
• Due Date: 08-May-2023
• Completion Date: 25-Apr-2023

Relations

• Revises: ISO 8639:2016 - Glass-reinforced thermosetting plastics (GRP) pipes and fittings - Test methods for leaktightness and proof of structural design of flexible joints
• Effective Date: 06-Jun-2022

Overview

ISO 8639:2023 specifies test methods for the leaktightness and structural proof of flexible socket-and-spigot joints with elastomeric sealing elements used in buried and aboveground glass‑reinforced thermosetting plastics (GRP) pipes and fittings. The standard defines type-testing procedures that subject joints to combinations of longitudinal extension (draw), angular deflection, compression/deformation perpendicular to the pipe axis and internal pressure, including negative (vacuum), cyclic and elevated static pressures. Tests are destructive and intended to prove the joint design for both pressure and non‑pressure applications across all nominal sizes.

Key topics and technical requirements

• Test scope: Flexible non‑thrust resistant socket-and-spigot joints for GRP pipelines; applicable to pressure and non‑pressure systems.
• Loading modes: Draw, total draw (including effects of angular deflection), angular movement (degrees), deformation (step caused by transverse load) and internal pressure.
• Pressure regimes: Negative (sub‑atmospheric), cyclic, and positive static pressures; leakage monitoring during pressurized tests.
• Apparatus & measurements:
  • Hydrostatic pressure source and vacuum pump for negative pressures.
  • Pressure gauges (accuracy ±2 %) and force measurement device (accuracy ±5 %).
  • Supports, straps/cradles and end‑sealing devices arranged per the test figures.
• Test pieces & conditioning:
  • Assembly of two pipe pieces joined by the joint under test; total effective length per referring standard.
  • Conditioning at test temperature for at least 24 h unless otherwise specified.
  • Typical testing uses one test piece for type tests.
• Inspection & reporting: Visual or alternative leakage detection (e.g., cameras, tracer dyes) where required; full test report required.

Practical applications

• Type testing and design verification for joint manufacturers to demonstrate that flexible GRP joints meet leaktightness and structural requirements.
• Independent test laboratories and certification bodies performing destructive tests to validate joint performance.
• Pipeline designers, specifiers and asset owners who need assurance that joints will perform under combined mechanical movements and pressure conditions encountered in buried and aboveground installations.
• Manufacturers of GRP pipe systems and fittings for product development and compliance evidence.

Who should use ISO 8639:2023

• GRP joint and seal designers
• Test laboratories and conformity assessment bodies
• Pipeline engineers and project specification authors
• Manufacturers seeking type‑approval or to support product standards compliance

Related standards

ISO 8639:2023 is intended to be referenced by product and application standards that define nominal size, pressure class, total effective length and test temperature for specific GRP systems. The document was prepared by ISO/TC 138 (Plastics pipes, fittings and valves for the transport of fluids).

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 8639
Third edition
2023-04
Glass-reinforced thermosetting
plastics (GRP) pipes and fittings —
Test methods for leaktightness and
proof of structural design of flexible
joints
Tubes et raccords en plastiques thermodurcissables renforcés de verre
(PRV) — Méthodes d'essai pour l'étanchéité et preuve de conception
structurelle de joint flexible
Reference number
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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 on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
6 Test pieces .5
6.1 Assembly . 5
6.2 Number . 6
7 Conditioning . 6
8 Test temperature . 6
9 Procedure .6
9.1 General . 6
9.2 Negative pressure . 6
9.3 Simultaneous angular deflection and draw . 7
9.4 Simultaneous draw and deformation . 7
9.5 Cyclic pressure . . 8
9.6 Positive static pressure. 8
10 Test report . 9
iii
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).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
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 third edition cancels and replaces the second edition (ISO 8639:2016), which has been technically
revised.
The main changes are as follows:
— Clause 2 "Normative References" has been introduced and the clauses that follow have been
renumbered;
— the title of Figure 1 has been modified;
— key reference 7 in Figure 2 has been modified.
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
Introduction
In a pipework system, pipes and fittings of different nominal pressures and stiffnesses may be used.
Any joint made between pipes and/or fittings should be designed such that its performance is equal to
or better than the requirements of the pipeline, but not necessarily of the components being joined.
The requirements for 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
specification.
v
INTERNATIONAL STANDARD ISO 8639:2023(E)
Glass-reinforced thermosetting plastics (GRP) pipes and
fittings — Test methods for leaktightness and proof of
structural design of flexible joints
1 Scope
This document specifies test methods for flexible non-thrust resistant socket-and-spigot joints with
elastomeric sealing elements for buried and aboveground glass-reinforced thermosetting plastics (GRP)
pipeline applications. It covers methods of test for the leaktightness and resistance to damage of the
joint only, when subject to specified combinations of longitudinal extension (draw), angular movement
(angular deflection), compression (deformation) perpendicular to the pipe axis and internal pressure.
This document is applicable to joints for either pressure or non-pressure applications.
NOTE 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.
These test procedures are applicable to joints for pipes and fittings of all nominal sizes. 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 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.
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 terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
pressure
hydrostatic gage pressure
3.2
angular deflection
angle between the axes of the joint and the consecutive pipe(s), expressed in degrees (°)
3.3
draw
longitudinal movement of the pipe relative to the socket (joint), expressed in millimetres (mm)
3.4
total draw
sum of the draw, and the additional longitudinal movement, of joint components due to the presence of
angular deflection, expressed in millimetres (mm)
3.5
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 in millimetres (mm)
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 combinations of draw, angular deflection 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.
In addition, a test at elevated positive static pressure is conducted to prove the structural design of the
coupling.
When under pressure, the joint is monitored for leakage.
Between each test condition (see Table 1) the joint is inspected for signs of damage.
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);
— sequence of testing, if appropriate (see 9.1);
— the joint positions (see Table 1);
— the draw, angular deflection (see 9.3) and the force, F (see 9.4);
— the permissible change in negative pressure (see 9.2.3).
5 Apparatus
5.1 End-sealing devices, of sizes and type appropriate to the components under test, anchored to
take the axial end thrust and permit free longitudinal movement.
5.2 Supports and restraints
5.2.1 Longitudinal supports, capable of supporting the end thrust induced by the internal pressure
but which shall not otherwise support the joint (see Figure 1, Figure 2 and Figure 3).
5.2.2 Straps or cradles, (100 ± 5) mm wide, supporting an arc of up to 180° of t
...