oSIST prEN 12814-2:2026

• Abstract:

  This document specifies the dimensions, the method of sampling, the preparation of the test specimens and the conditions for performing the tensile test in order to determine the short-term tensile welding factor.; A tensile test can be used in conjunction with other tests (e.g. bend, tensile creep, macro) to assess the performance of welded assemblies, made from thermoplastics materials.; The test is applicable to welded semi-finished products made from thermoplastics materials filled or unfilled, but not reinforced, irrespective of the welding process used.

• Status: Not Published
• Public Enquiry End Date: 30-Jul-2026
• ICS: 25.160.40 - Welded joints and welds
• ICS: 83.080.01 - Plastics in general
• Technical Committee: IPMA - Polimer materials and products
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 02-Jun-2026
• Due Date: 20-Oct-2026
• Completion Date: 03-Aug-2026
• Ref Project: prEN 12814-2 - Testing of welded joints of thermoplastics semi-finished products - Part 2: Tensile test

• Revises: SIST EN 12814-2:2021 - Testing of welded joints of thermoplastics semi-finished products - Part 2: Tensile test
• Effective Date: 02-Jul-2025

oSIST prEN 12814-2:2026 is the Slovenian publication of draft European Standard prEN 12814-2:2026 from CEN. It specifies how to sample, prepare and tensile-test welded thermoplastics semi-finished products to determine the short-term tensile welding factor. The document is used for filled or unfilled, not reinforced, thermoplastic welded assemblies, regardless of the welding process.

What does oSIST prEN 12814-2:2026 specify?

oSIST prEN 12814-2:2026 covers the tensile test for welded joints of thermoplastics semi-finished products. It sets the specimen dimensions, sampling, cutting, conditioning, test speed, equipment and the calculation and reporting of results.

The scope also states that the tensile test may be used together with bend, tensile creep and macro tests to assess the performance of welded assemblies.

The document is organized into clauses 1 to 11, with two informative annexes.

Annex	What it covers
Annex A	Tensile test specimen for overlap joints
Annex B	Recommended test speeds for some thermoplastics materials

What are the key requirements of oSIST prEN 12814-2:2026?

oSIST prEN 12814-2:2026 is built around a simple comparison between welded and unwelded specimens. In practice, it tells a laboratory how to prepare the pieces, run the test and decide the short-term tensile welding factor.

• Clause 5 - Sampling procedures: Welded and unwelded specimens are cut perpendicular to the welded joint at least eight hours after welding, marked to keep track of their original position, and not heat treated or mechanically straightened. This matters because the test should reflect the weld as made, not a modified specimen.

• Clause 6 - Specimen dimensions: The standard gives two specimen types for flat and tubular assemblies, with sizes selected from tube diameter or specimen thickness. For small tubes, the whole tube is tested. Where beads remain in service, they stay on the specimen; where they are removed in service, they are removed before testing. Annex A gives the geometry for overlap joints.

• Clause 7 - Cutting: Specimens are cut with parallel sides, heating during cutting is minimized, and cutting must not create notches. A visual examination of the weld according to EN 13100-1 is then carried out and recorded. This helps separate weld quality from damage introduced during preparation.

• Clause 8 - Mechanical testing: Specimens are conditioned at 23 °C and tested at room temperature unless otherwise specified. Test speed follows EN ISO 527-1 and should be chosen so the test ends in about one minute. At least five welded and five unwelded specimens are tested, with the same geometry, the same speed and the same clamp spacing. Annex B gives example speeds for some thermoplastics materials.

• Clause 8 note and Clause 10: If welded specimens fail or yield within the calibrated length but outside the weld, the unwelded specimens need not be tested and the short-term tensile welding factor is taken as 1. For certain materials, a waisted specimen may be useful when failure needs to be driven into the weld.

• Clause 9 - Equipment: The test machine must comply with ISO 5893 and move the crosshead continuously and uniformly.

• Clause 10 - Result calculation and invalid failures: The short-term tensile welding factor is calculated from the average stresses of welded and unwelded specimens. If yielding occurs before fracture, yield stress is used. Failures only count as clamp failures within defined distances from the jaws, and if type 1 specimens repeatedly fail in the clamps, type 2 specimens are used instead.

• Clause 11 - Test report: The report records specimen identity, weld appearance, specimen geometry, test temperature, speed, force and stress values, the calculated factor, deviations, unusual features, the laboratory, the date and the responsible person.

What terms does oSIST prEN 12814-2:2026 define?

oSIST prEN 12814-2:2026 uses these key symbols and abbreviated terms in the test calculation and specimen description.

• Short-term tensile welding factor, f_s - the ratio used to compare the tensile strength of welded specimens with unwelded specimens.
• Calibrated and parallel length, L_o - the measured test length used for the main tensile section of the specimen.
• Nominal outside diameter, D_n - the tube size used to select specimen dimensions for tubular assemblies.
• Maximum width of the weld bead, L_b - the widest bead dimension, recorded where relevant to the specimen geometry.
• Type 1 test specimen - the standard specimen geometry shown in Figure 1 and Table 1 for flat and tubular assemblies.
• Type 2 test specimen - the alternative specimen geometry shown in Figure 2 and Table 2, used when type 1 specimens fail in the clamps.
• Welded test specimen - a specimen taken from a welded piece and used to measure weld performance.
• Unwelded test specimen - a reference specimen taken from the same test piece and used to calculate the welding factor.

Who uses oSIST prEN 12814-2:2026?

oSIST prEN 12814-2:2026 is used by test laboratories, manufacturers of thermoplastics semi-finished products, and quality teams that need to check weld performance. It is also relevant where welding parameters are being optimized or where welders are being qualified, because the test can be used to compare welded and unwelded performance in a controlled way.

What changed in oSIST prEN 12814-2:2026 from the previous edition?

oSIST prEN 12814-2:2026 supersedes EN 12814-2:2021.

• The minimum test specimen lengths have been revised.
• Annex C, which covered a notched tensile test specimen, has been deleted.

Which standards are used with oSIST prEN 12814-2:2026?

Standard	Contribution
EN ISO 291	Standard atmospheres for conditioning and testing plastics specimens
EN 13100-1	Visual examination of welded joints of thermoplastics semi-finished products
EN ISO 527-1	General principles for tensile testing of plastics, including test speed rules
ISO 5893	Requirements for tensile, flexural and compression test equipment

Related standards named in the document also help users choose or compare methods:

Standard	Contribution
EN 13067	Welder qualification testing for thermoplastics welded assemblies
EN 12814-7	Tensile test with waisted test specimens
ISO 13953	Tensile strength test for specimens from a butt-fused joint

What does the oSIST prEN 12814-2:2026 document contain?

oSIST prEN 12814-2:2026 contains the full test procedure, from specimen selection to reporting. Clause 6 gives the specimen dimensions in tables and figures for flat and tubular assemblies, and Annex A gives the overlap-joint specimen. Annex B provides example test speeds for selected materials.

Clause 10 gives the calculation method for the short-term tensile welding factor using the mean stresses of welded and unwelded specimens. Clause 11 gives the reporting checklist, including geometry, temperatures, speed, force values, calculated stresses and the final factor.

SLOVENSKI STANDARD
01-julij-2026
Preskušanje zvarjenih spojev plastomernih polizdelkov - 2. del: Natezni preskus
Testing of welded joints of thermoplastics semi-finished products - Part 2: Tensile test
Prüfen von Schweißverbindungen an Halbzeugen aus thermoplastischen Kunststoffen -
Teil 2: Zugversuch
Essais des assemblages soudés sur produits semi-finis en thermoplastiques - Partie 2 :
Essai de traction
Ta slovenski standard je istoveten z: prEN 12814-2
ICS:
25.160.40 Varjeni spoji in vari Welded joints and welds
83.080.01 Polimerni materiali na Plastics in general
splošno
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2026
ICS 25.160.40 Will supersede EN 12814-2:2021
English Version
Testing of welded joints of thermoplastics semi-finished
products - Part 2: Tensile test
Essais des assemblages soudés sur produits semi-finis Prüfen von Schweißverbindungen an Halbzeugen aus
en thermoplastiques - Partie 2 : Essai de traction thermoplastischen Kunststoffen - Teil 2: Zugversuch
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 249.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12814-2:2026 E
worldwide for CEN national Members.

prEN 12814 2:2026
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms, definitions, symbols and abbreviated terms . 4
3.1 Terms and definitions . 4
3.2 Symbols and abbreviated terms . 4
4 Principle of the test . 5
5 Sampling procedures . 5
6 Dimensions of test specimens . 5
7 Cutting of test specimens . 7
8 Mechanical testing . 7
9 Test equipment . 8
10 Determination of the short-term tensile welding factor . 8
11 Test report . 8
Annex A (informative) Tensile test specimen for overlap joints . 10
Annex B (informative) Recommended test speeds for some thermoplastics materials . 11
Bibliography . 12
European foreword
This document (prEN 12814-2:2026) has been prepared by Technical Committee CEN/TC 249 “Plastics”,
the secretariat of which is held by SIS.
This document is currently submitted to the CEN enquiry.
This document supersedes EN 12814-2:2021.
In comparison with the previous edition, the following technical modifications have been made:
— the minimum test specimen lengths have been revised;
— Annex C (notched tensile test specimen) has been deleted.
prEN 12814 2:2026
1 Scope
This document specifies the dimensions, the method of sampling, the preparation of the test specimens and
the conditions for performing the tensile test in order to determine the short-term tensile welding factor.
A tensile test can be used in conjunction with other tests (e.g. bend, tensile creep, macro) to assess the
performance of welded assemblies, made from thermoplastics materials.
The test is applicable to welded semi-finished products made from thermoplastics materials filled or
unfilled, but not reinforced, irrespective of the welding process used.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
EN ISO 291, Plastics — Standard atmospheres for conditioning and testing(ISO 291)
EN 13100-1, Non destructive testing of welded joints of thermoplastics semi-finished products — Part 1:
Visual examination
EN ISO 527-1, Plastics — Determination of tensile properties - Part 1: General principles (ISO 527-1)
ISO 5893, Rubber and plastics test equipment — Tensile, flexural and compression types (constant rate of
traverse) — Specification
3 Terms, definitions, symbols and abbreviated terms
3.1 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.2 Symbols and abbreviated terms
For the purposes of this document, the following symbols and abbreviated terms apply:
a minimum measured thickness of the test specimen within mm
calibrated and parallel length
a nominal thickness of the test piece mm
n
b width of calibrated and parallel length of the test specimen mm
b width of shoulder of the test specimen mm
nominal outside diameter of the tube mm
Dn
F the value of force of the unwelded test specimens taken from the N
r
same test piece, used in the calculation of f
s
f the short-term tensile welding factor None
s
F the value of force of the welded test specimen used in the N
w
calculation of f
s
L total length of t
...