ISO 18851:2015

INTERNATIONAL ISO
STANDARD 18851
First edition
2015-03-15
Plastics piping systems — Glass-
reinforced thermosetting plastics
(GRP) pipes and fittings — Test method
to prove the structural design of fittings
Systèmes de canalisation en matières plastiques — Tubes et raccords
plastiques thermodurcissables renforcés de verre (PRV) — Méthode
d’essai pour prouver la conception structurelle des raccords
Reference number
©
ISO 2015
© ISO 2015
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Published in Switzerland
ii © ISO 2015 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Terms and definitions . 1
3 Principle . 1
4 Apparatus . 2
4.1 End sealing devices . 2
4.1.1 General. 2
4.1.2 Capable of applying the end loads . 2
4.1.3 Not capable of applying the end loads . 2
4.2 Supports . 2
4.2.1 End thrust supports . 2
4.2.2 Straps and Cradles . 2
4.3 Source of hydrostatic pressure . 2
4.4 Means to measure the gauge pressure . 2
5 Test pieces . 2
5.1 Test arrangement . 2
5.2 Number of test pieces . 3
6 Conditioning . 4
7 Test temperature . 4
8 Procedure. 4
8.1 Tests to be performed . 4
8.2 Test Failure Criteria . 4
8.2.1 Bursting . 4
8.2.2 Leaking . 4
8.2.3 Weeping . 4
8.3 Initial leakage . 4
8.4 Resistance to internal pressure . 5
9 Test report . 5
Bibliography . 7
Foreword
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The committee responsible for this document is ISO/TC 138, Plastics pipes, fittings and valves for the
transport of fluids, Subcommittee SC 6, Reinforced plastics pipes and fittings for all applications.
iv © ISO 2015 – All rights reserved

INTERNATIONAL STANDARD ISO 18851:2015(E)
Plastics piping systems — Glass-reinforced thermosetting
plastics (GRP) pipes and fittings — Test method to prove
the structural design of fittings
1 Scope
This International Standard specifies methods of test for fittings of any form, i.e. bends, branches, tapers,
intended to be used in plastics piping systems for pressure and non-pressure drainage and sewerage or water
supply made of glass-reinforced thermosetting plastics (GRP). This International Standard is applicable to
fittings, in order to test their structural design, but is not applicable to connecting joint systems. It assumes
that the fitting either is or is not intended to be subject to the effects of hydrostatic end thrust.
The tests detailed in 8.1 to 8.4 are applicable to fittings intended to be used in buried or non-buried
applications.
These test procedures are applicable to fittings of all nominal sizes specified in the referring standard.
The tests are for evaluating fittings intended for use in applications conveying liquids at temperatures
specified in the referring standards.
The test procedures in this International Standard are damaging to the test piece which will
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