ISO 13956:2025

International
Standard
ISO 13956
Second edition
Plastics pipes and fittings —
2025-11
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
Reference number
© ISO 2025
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ii
Contents Page
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
5.4 Test equipment — Type C .3
6 Sampling . 4
6.1 Preparation of test pieces .4
6.2 Number of test pieces .5
7 Conditioning . 5
8 Procedure . 5
9 Test report . 7
Annex A (informative) Recommendation . 9
Bibliography .10

iii
Foreword
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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:
— a Note has been added to the scope;
— guidance on assessment of air pockets in the fusion zone has been given in Clause 8, Figure 5 and Figure 6;
— symbols have been aligned with relevant ISO documents;
— 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.html.

iv
International Standard ISO 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 The applicability of this method depends upon the design of the saddle. If not applicable, the strip-bend test
[1]
according to ISO 21751 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/ obp
— IEC Electropedia: available at 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 t
...