ISO 8513:2016

INTERNATIONAL ISO
STANDARD 8513
Third edition
2016-02-01
Plastics piping systems — Glass-
reinforced thermosetting plastics
(GRP) pipes — Test methods for
the determination of the initial
longitudinal tensile strength
Systèmes de canalisations en plastiques — Tubes en plastiques
thermodurcissables renforcés de verre (PRV) — Méthodes d’essai pour
la détermination de la force en traction longitudinale
Reference number
ISO 8513:2016(E)
©
ISO 2016

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ISO 8513:2016(E)

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ISO 8513:2016(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Terms and definitions . 1
3 Principle . 2
4 Apparatus . 3
5 Test pieces . 3
5.1 General . 3
5.2 Strip test piece (method A) . 4
5.2.1 Shape . 4
5.2.2 Dimensions . 4
5.2.3 Use of built-up ends . 6
5.3 Pipe section test pieces (method B) . 6
5.4 Number of test pieces . 6
6 Conditioning . 6
7 Test temperature . 6
8 Procedure (methods A and B) . 7
9 Calculation . 7
9.1 For strip test pieces (method A) . 7
9.2 For pipe test pieces (method B) . 7
10 Test report . 8
Annex A (informative) Determination of longitudinal properties for helically filament-
wound thin wall pipe . 9
Bibliography .11
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ISO 8513:2016(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 6, Reinforced plastics pipes and fittings for all applications.
This third edition cancels and replaces the second edition (ISO 8513:2014) which has been
technically revised.
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ISO 8513:2016(E)

Introduction
Although this International Standard was revised in 2014, it was found necessary to again revise
to correct several small errors in presentation and to revise the allowable testing speed (crosshead
movement) range. A review of ISO testing standards for glass-reinforced thermosetting plastics (GRP)
materials and the results of a recent testing program indicated that a testing speed of 2 mm/min to
5 mm/min is more appropriate. Also, evidence was presented that method C, the plate method, lead to
results that were frequently from shear failures rather than tensile failures and lead to a falsely high
prediction of Longitudinal Tensile Strength. Method C has been removed from this edition. Also, the
term “Apparent” was removed from the title as it seemed to have no clear meaning.
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INTERNATIONAL STANDARD ISO 8513:2016(E)
Plastics piping systems — Glass-reinforced thermosetting
plastics (GRP) pipes — Test methods for the determination
of the initial longitudinal tensile strength
1 Scope
This International Standard specifies two test methods for determining the longitudinal tensile
properties of glass-reinforced thermosetting plastics (GRP) pipes. The properties which can be
determined are
— the longitudinal tensile strength, and
— the percentage ultimate elongation.
Method A uses, for the test piece(s), a longitudinal strip cut from a pipe.
Method B uses a specified length of the full cross-section of the pipe.
Method A is applicable to pipes with a nominal size of DN 50 or greater with circumferentially wound
filaments, with or without chopped glass and/or woven rovings and/or fillers, and to centrifugally cast
pipes. It is applicable to pipes with helically wound filaments with a nominal size of DN 200 or greater.
Method B is applicable to all types of GRP pipe. It is usually used for pipes with a nominal size up to and
including DN 150.
Results from one method are not necessarily equal to the results derived from any of the alternative
methods. However, all methods have equal validity.
Annex A describes additional considerations for method B that have been found useful for the testing of
thin-walled helically wound pipes and can be used to supplement the basic text.
NOTE This International Standard does not address the determination of longitudinal tensile modulus.
Due to the multi-layer construction of many GRP pipes, the accurate measurement of strain, necessary for
modulus determination, can be very difficult. If it is desired to determine longitudinal modulus, see ISO 527-4
and/or ISO 527-5.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
helical wound
refers to filament-wound pipes made with a balanced winding angle
Note 1 to entry: Sometimes called cross wound.
2.2
longitudinal tensile strength
σ *
LA
σ *
LB
maximum tensile force in the longitudinal direction per unit mean circumference at failure
Note 1 to entry: It is expressed in newtons per millimetre of the circumference (N/mm).
Note 2 to entry: The subscripts A and B denote the method of test used.
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ISO 8513:2016(E)

2.3
mean circumference
circumference corresponding to the mean diameter multiplied by π (π ≈ 3,141 6)
Note 1 to entry: It is expressed in millimetres.
2.4
mean diameter
d
m
diameter of the circle corresponding with the middle of the pipe wall cross-section
Note 1 to entry: It is given by any of the following:
a) the average of the external diameter of the pipe minus the average of the wall thickness;
b) the external circumference of the pipe divided by π (π ≈ 3,141 6) minus the average of the wall thickness;
c) the average of the internal diameter of the pipe plus the average of the wall thickness.
Note 2 to entry: It is expressed in millimetres.
2.5
ultimate longitudinal tensile stress
σ
L,ULT
maximum longitudinal tensile force per unit cross-sectional area at failure
Note 1 to entry: It is expressed in newtons per square millimetre (N/mm).
2.6
ultimate elongation
ε
L
elongation coincident with the ultimate longitudinal tensile stress
Note 1 to entry: For the purposes of this International Standard, the measurement of elongation is limited to
measurement of the movement of the tensile testing machine cross-heads.
Note 2 to entry: It is expressed as a percentage of an initial gauge length or free length of a test piece.
3 Principle
Test pieces comprising either strips cut longitudinally from a pipe wall segment (method A) or a
specified length of pipe (method B) are subjected to extension in the longitudinal direction at a constant
speed such that fracture occurs within a specified time.
The tensile properties are determined using the initial dimensions of the test piece, the tensile force,
and the cross-head movement.
NOTE It is assumed that the following test parameters are set by the standard making reference to this
International Standard:
a) the methods to be used, i.e. method A or method B;
b) the number of tes
...