ISO 8513:2023

INTERNATIONAL ISO
STANDARD 8513
Fourth edition
2023-07
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 2023
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ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 3
5.1 Tensile-testing machine . 3
5.2 Grips . 3
5.3 Dimension measurement devices . 4
6 Test pieces .4
6.1 General . 4
6.2 Strip test piece (method A) . 4
6.2.1 Shape . 4
6.2.2 Dimensions . 4
6.2.3 Use of built-up ends . 6
6.3 Pipe section test pieces (method B) . 6
6.4 Number of test pieces . 6
7 Conditioning . 7
8 Test temperature . 7
9 Procedure (methods A and B) .7
10 Calculation . 7
10.1 For strip test pieces (method A) . 7
10.2 For pipe test pieces (method B) . 8
11 Test report . 8
Annex A (informative) Determination of longitudinal properties for helically filament-
wound thin wall pipe .10
Bibliography .12
iii
Foreword
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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 fourth edition cancels and replaces the third edition (ISO 8513:2016), which has been technically
revised.
The main changes are as follows:
— subclause 6.2.3 has been modified to allow the manufacturer to choose to utilize built-up ends on
the samples, independent of the grips holding the test piece (see 6.2.3).
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
INTERNATIONAL STANDARD ISO 8513:2023(E)
Plastics piping systems — Glass-reinforced thermosetting
plastics (GRP) pipes — Test methods for the determination
of the initial longitudinal tensile strength
1 Scope
This document specifies two test methods (method A and method B) 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 document 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 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
helically filament-wound
cross wound
filament-wound pipes made with a balanced winding angle
3.2
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.
3.3
mean circumference
circumference corresponding to the mean diameter multiplied by π
Note 1 to entry: π ≈ 3,141 6.
Note 2 to entry: It is expressed in millimetres (mm).
3.4
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 (mm).
3.5
ultimate elongation
ε
L
elongation coincident with the ultimate longitudinal tensile strength.
Note 1 to entry: For the purposes of this document, 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.
4 Principle
Test pieces comprising of 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 usin
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