ISO 8513:2014

INTERNATIONAL ISO
STANDARD 8513
Second edition
2014-05-01
Plastics piping systems — Glass-
reinforced thermosetting plastics
(GRP) pipes — Test methods for the
determination of the apparent 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 apparente
Reference number
ISO 8513:2014(E)
©
ISO 2014

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ISO 8513:2014(E)

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© ISO 2014
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ISO 8513:2014(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Terms and definitions . 1
3 Principle . 2
4 Apparatus . 3
5 Test pieces . 4
5.1 General . 4
5.2 Strip test piece (method A) . 5
5.3 Pipe section test pieces (method B) . 7
5.4 Plate test pieces (method C) . 7
5.5 Number of test pieces . 9
6 Conditioning . 9
7 Test temperature . 9
8 Procedure (methods A, B, and C) .10
9 Calculation .10
9.1 For strip test pieces (method A) .10
9.2 For pipe test pieces (method B) .11
9.3 For plate test pieces (method C) .11
10 Test report .12
Annex A (informative) Determination of longitudinal properties for helically filament-wound thin
wall pipe .14
Bibliography .16
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ISO 8513:2014(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 which has been technically revised.
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INTERNATIONAL STANDARD ISO 8513:2014(E)
Plastics piping systems — Glass-reinforced thermosetting
plastics (GRP) pipes — Test methods for the determination
of the apparent initial longitudinal tensile strength
1 Scope
This International Standard specifies three 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 C uses a notched plate cut from a pipe wall section.
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.
Method C is primarily intended for use for helically wound pipes with a winding angle other than
approximately 90°. This method can also be used for other types of pipe.
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 test method 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, it is recommended that
ISO 527-4 and/or ISO 527-5 be consulted.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
helical wound
sometimes called cross wound, refers to filament-wound pipes made with a balanced winding angle
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ISO 8513:2014(E)

2.2
longitudinal tensile strength
σ *
LA
σ *
LB
σ *
LC
maximum tensile force in the longitudinal direction per unit mean circumference at failure (the
subscripts A, B, and C denote the method of test used)
Note 1 to entry: It is expressed in newtons per millimetre of the circumference (N/mm).
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 approximately 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), a specified
length of pipe (method B), or a notched plate cut from a pipe wall section (method C) 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:
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ISO 8513:2014(E)

a) the methods to be used, i.e. method A, method B, or method C;
b) the number of test pieces (see 5.5);
c) if applicable, the requirements for conditioning, e.g. temperature, humidity, time, and associated tolerances
(see Clause 6);
d) the test temperature and its tolerance (see Clause 7);
e) the properties to be measured (see Clause 8).
4 Apparatus
4.1 Tensile-testing machine, of the constant rate of cross-head movement type, incorporating the
following features:
a) a fixed part, fitted with a grip to hold one end of the test piece without permitting any longitudinal
movement thereof, and a moveable part, incorporating a grip to hold the other end of the test piece
during extension (the fixed and moving parts and their associated grips (see 4.2) shall enable
the test piece to be aligned when a force is applied so that its longitudinal axis coincides with the
direction of this force);
b) a drive mechanism, capable of imparting a constant speed (see 8.3) to the moving part;
c) a force indicator, capable of measuring the force applied to a test piece which is held in the grips
(the mechanism shall be free from significant inertia lag at the necessary speed of testing and shall
indicate or record force, or consequent stress, with an accuracy of within ±1 % of the value to be
measured);
d) a means to measure the cross-head movement as a function of the applied load.
4.2 Grips, for holding the test piece.
Each of the two grips shall be capable of holding one end of the test piece without slip or crushing to an
extent that will affect the results obtained. Grips which tighten automatically might be suitable. Typical
grips for a pipe section test piece (see 5.3) are shown in Figure 1.
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ISO 8513:2014(E)

Key
1 mandrel
2 segmented grips
3 sleeve
4 reinforcing band
5 tes
...