ISO 7509:2015

INTERNATIONAL ISO
STANDARD 7509
Second edition
2015-03-01
Plastics piping systems — Glass-
reinforced thermosetting plastics
(GRP) pipes — Determination of time
to failure under sustained internal
pressure
Systèmes de canalisations en plastiques — Tubes en plastiques
thermodurcissables renforcés de verre (PRV) — Détermination du
temps mis jusqu’à la défaillance sous une pression interne constante
Reference number
ISO 7509:2015(E)
©
ISO 2015

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ISO 7509:2015(E)

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© ISO 2015
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ii © ISO 2015 – All rights reserved

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ISO 7509:2015(E)

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 . 4
6.1 Number . 4
6.2 Free length . 4
6.3 Cutting . 4
7 Conditioning . 4
8 Procedure. 4
9 Detection of failure . 5
9.1 General . 5
9.2 Detection methods . 5
9.2.1 Loss of test liquid . . 5
9.2.2 Drop in electrical resistance . 6
10 Test report . 6
Annex A (informative) Electronic leak/weep detection . 7
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ISO 7509:2015(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).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT), see the following URL: Foreword — Supplementary information.
The committee responsible for this document is ISO/TC 138, Plastics pipes, fittings and valves for the
transport of fluids, Subcommittee SC 06, Reinforced plastics pipes and fittings for all applications.
This second edition cancels and replaces the first edition (ISO 7509:2000), which has been technically
revised.
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ISO 7509:2015(E)

Introduction
This International Standard describes a method for determining the long-term resistance to internal
pressure of glass-reinforced thermosetting plastics (GRP) pipes.
It is a method which uses the following conditions:
— water as the reference liquid inside the test piece;
— water or air, as the environment outside the test piece.
The method can be used for tests at different temperatures. It should be noted that, for a given
temperature, the results obtained can differ depending on the end loading conditions and whether the
external environment is water or air.
The method described in this International Standard differs from those in some other similar standards
in the following details:
— the failure criteria and the detection of failure;
— the strain in the longitudinal and circumferential directions can be measured during the test;
— the test pressure is maintained constant.
This method can be used to obtain data to establish internal pressure versus time-to-failure relationships
at different temperatures. The procedures for establishing the relationships are not within the scope of
this International Standard. For such purposes, attention is drawn to ISO 10928.
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INTERNATIONAL STANDARD ISO 7509:2015(E)
Plastics piping systems — Glass-reinforced thermosetting
plastics (GRP) pipes — Determination of time to failure
under sustained internal pressure
1 Scope
This International Standard specifies a method for determining the time-to-failure of glass-reinforced
thermosetting plastics (GRP) pipes under internal hydrostatic pressure at a specified temperature. The
external environment can be air or water.
NOTE For other internal or external environments, the referring standard is to specify any additional requirement.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 3126, Plastics piping systems — Plastics components — Determination of dimensions
ISO 10928, Plastics piping systems — Glass-reinforced thermosetting plastics (GRP) pipes and fittings —
Methods for regression analysis and their use
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
failure
occurrence of bursting, leaking, or weeping
Note 1 to entry: See 9.1.
3.2
bursting
failure by rupture of the pipe wall with immediate loss of test liquid and drop of pressure
Note 1 to entry: See 9.1 and 9.2.1.
3.3
leaking
failure by visible loss of the pressurizing liquid through the pipe wall to an extent detectable visually
and/or by a continuous drop in pressure
Note 1 to entry: See 9.1 and 9.2.1
3.4
weeping
failure by passage of the pressurizing liquid through the pipe wall to an extent detectable visually
and/or electronically
Note 1 to entry: See 9.1 and 9.2.2.
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ISO 7509:2015(E)

4 Principle
A cut length of pipe at the required temperature is subjected to a specified internal hydrostatic pressure
to cause a state of stress in the pipe wall, which depends upon the loading conditions (i.e. with or wit
...