ISO/FDIS 13956

ISO/DIS FDIS 13956:2025(en)
ISO /TC 138/SC 5/WG 12
Secretariat: NEN
Date: 2024-12-10
Plastics pipes and fittings — Decohesion test of polyethylene (PE)
saddle fusion joints — Evaluation of ductility of fusion joint interface
by tear test
Tubes et raccords en matières plastiques — Essai de décohésion des selles en polyéthylène (PE) assemblées par
soudage — Évaluation de la ductilité de l'interface de soudage par essai d'arrachement
FDIS stage
ISO #####-#:####(X/FDIS 13956:2025(en)
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ii © ISO #### 2025 – All rights reserved
ii
ISO/DISFDIS 13956:2025(en)
Contents
Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
6 Sampling . 7
7 Conditioning . 8
8 Procedure . 8
9 Test report . 13
Annex A (informative) Recommendation . 14
Bibliography . 15

Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
5.1 General . 1
5.2 Tensile test equipment – Type A1 or A2 . 1
5.3 Compressive test equipment – Type B . 3
a) Compression testing machine . 3
b) Loading pin . 3
c) Appropriate clamping device . 3
5.4 Test equipment – Type C . 4
a) Tensile testing machine . 4
b) Appropriate clamping device . 4
c) Appropriate supporting frame with fixtures . 4
6 Sampling . 6
6.1 Preparation of test pieces . 6
6.2 Number of test pieces . 6
7 Conditioning . 6
8 Procedure . 6
9 Test report . 10
Annex A (informative) Recommendation . 11
Bibliography . 12

iii
ISO #####-#:####(X/FDIS 13956:2025(en)
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
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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).
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Organization (WTO) principles in the Technical Barriers to Trade (TBT), see 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 5, General properties of pipes, fittings and valves of plastic materials and
their accessories — Test methods and basic specifications.
This second edition cancels and replaces the first edition (ISO 13956:2010), which has been technically
revised.
The main changes are as follows:
— — Notes werea Note has been added to the scope;
— — Guidanceguidance on assessment of air pockets in the fusion zone, has been given in Clause 8, Fig 58,
Figure 5 and Fig 6.Figure 6;
— — Alignment of symbols have been aligned with relevant ISO documents;
— Correction in figure 5
— Figure 5 has been corrected.
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.htmlwww.iso.org/members.html.
iv © ISO #### 2025 – All rights reserved
iv
DRAFT International Standard ISO/DIS 13956:2025(en)

Plastics pipes and fittings — Decohesion test of polyethylene (PE)
saddle fusion joints — Evaluation of ductility of fusion joint interface
by tear test
1 Scope
This document specifies a method for the evaluation of the ductility of the fusion joint interface of assemblies
of polyethylene (PE) pipe and electrofusion saddles, intended for the conveyance of fluids.
NOTE 1 The applicability of this method depends upon the design of the saddle. If not applicable, the strip-bend test
[1][ ]
according to ISO 21751 0 is considered an alternative.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obphttps://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/https://www.electropedia.org/
4 Principle
A load is applied to the saddle of an assembly of an electrofusion saddle fused onto pipe.
The ductility of the fusion joint interface is characterised by the appearance of the failure in the fusion plane
and by the determination of the percentage of brittle fracture.
5 Apparatus
5.1 General
The test apparatus shall comprise a tensile equipment type A1 or A2, as indicated in Figures 1Figures 1 and
22 respectively, or a compressive equipment type B as indicated in Figure 3.Figure 3. For nominal outside pipe
diameter ≥ 250 mm, equipment type C as indicated in Figure 4Figure 4 can be used.
5.2 Tensile test equipment –— Type A1 or A2
The tensile equipment shall include the following main parts:
a) a) Tensiletensile testing machine, capable of maintaining a speed of (100 ± 10) mm/min, with
sufficient force to separate the saddle from the pipe.;
b) b) Loadingloading pin, with an outside diameter of at least ½ nominal outside diameter of the
pipe and allowing rotation.;
c) c) Appropriateappropriate clamping device, to grip the saddle and allow separation from the
pipe.
NOTE The type A1 clamping device allows symmetrical loading of the saddle from both sides (an example is shown
in Figure 1).Figure 1). The type A2 clamping device grips the saddle only from one side (an example is shown in
Figure 2).Figure 2).
Key
1 PE saddle
2 PE pipe
3 loading pin
4 clamping device
F decohesion force
1 PE saddle
2 PE pipe
3 loading pin
2 © ISO #### 2025 – All rights reserved
ISO/DISFDIS 13956:2025(en)
4 clamping device
F decohesion force
Figure 1 — Typical type A1 test arrangement

Key
1 PE saddle
2 PE pipe
3 loading pin
4 clamping device, allowing rotation of the loading point
F decohesion force
1 PE saddle
2 PE pipe
3 loading pin
4 clamping device, allowing rotation of the loading point
F decohesion force
Figure 2 — Typical type A2 test arrangement
5.3 Compressive test equipment –— Type B
The compression equipment shall include the following main parts:
a) a) Compressioncompression testing machine, capable of maintaining a speed of
(100 ± 10) mm/min, with sufficient force to separate the saddle from the pipe;
b) b) Loadingloading pin, with an outside diameter of at least ½ of the nominal outside diameter of
the pipe;
c) c) Appropriateappropriate clamping device, to grip or support the saddle and allow separation
from the pipe (an example is shown in Figure 3).Figure 3).

Key
1 PE saddle
2 PE pipe
3 loading pin
4 clamping device
F decohesion force
1 PE saddle
4 © ISO #### 2025 – All rights reserved
ISO/DISFDIS 13956:2025(en)
2 PE pipe
3 loading pin
4 clamping device
F decohesion force
Figure 3 — Typical type B compression mode test arrangement
5.4 Test equipment –— Type C
The test equipment shall include the following main parts:
a) a) Tensiletensile testing machine, capable of maintaining a speed of (100 ± 10) mm/min, with
sufficient force to separa
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