National foreword

This British Standard is the UK implementation of EN 15425:2023. It supersedes BS EN 15425:2017, which is withdrawn.

The UK participation in its preparation was entrusted to Technical Committee PRI/52, Adhesives.

A list of organizations represented on this committee can be obtained on request to its committee manager.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 28 February 2023.

This European Standard was approved by CEN on 18 December 2022.

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. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.

This European Standard exists 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.

European foreword

This document (EN 15425:2023) has been prepared by Technical Committee CEN/TC 193 “Adhesives”, the secretariat of which is held by UNE.

This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by August 2023, and conflicting national standards shall be withdrawn at the latest by August 2023.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN 15425:2017.

EN 15425:2023 includes the following significant technical changes with respect to EN 15425:2017:

for adhesive type “Special purpose”, the test according to EN 302‑8 is performed with a bond line thickness of 0,5 mm;
an additional adhesive subtype I-SP-70-0,5 has been added in Table 1;
for adhesive type FJ, the test according to EN 302‑2 is required only with short closed assembly time, and the test according to EN 15416‑5 is only required with thin glue line;
for finger joint delamination tests on additional wood species, the reference to EN 301 has been replaced by a new Annex B;
for the delamination test according to EN 302‑2 with preservative treated wood, a test with Scots pine (Pinus sylvestris) and silver fir (Abies alba) covers also Norway spruce (Picea abies L.);
the description of the test procedure for an “adhesive line” has been modified;
the description of a test procedure when a primer is used in all bonding operations has been added in Clause 4;
provisions and maximum tolerance for testing and application of a primer have been added in 5.1;
information on water spraying has been included in the scope and as a new Annex C.

Any feedback and questions on this document should be directed to the users’ national standards body. A complete listing of these bodies can be found on the CEN website.

According to the CEN-CENELEC Internal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: 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 the United Kingdom.

Introduction

This document is one of a series dealing with one component polyurethane adhesives for use with timber structures, and is published in support of product standards for load-bearing timber structures in connection with EN 1995‑1‑1, Eurocode 5: Design of timber structures — Part 1-1: General — Common rules and rules for buildings.

The series consists of:

one standard for classification and performance requirements (EN 15425);
eight test methods (EN 302‑1, EN 302‑2, EN 302‑3, EN 302‑4, EN 302‑8, EN 15416‑1 (“Glass house test”), EN 15416‑3 and Annex B of this document) used to assess the performance of adhesives after specified heat and humidity treatments; and
three test methods (EN ISO 2555 (reference in EN 302‑7), EN 15416‑4, and EN 15416‑5) to characterize the working properties of the adhesives.

Safety statement

Persons using this document should be familiar with the normal laboratory practice, if applicable. This document cannot address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any regulatory conditions.

Environmental statement

It is understood that some of the material permitted in this document may have negative environmental impact. As technological advantages lead to better alternatives for these materials, they will be eliminated from this European Standard to the extent possible.

At the end of the test, it is recommended that the users of this document take care to carry out an appropriate disposal of the wastes, according to local regulations.

1 Scope

This document establishes a classification for one component polyurethane (PUR) adhesives according to their suitability for use in load-bearing timber products in defined climatic exposure conditions, and specifies performance requirements for such adhesives for the factory manufacture or factory-like manufacturing of load-bearing timber products only.

It also classifies “adhesive product lines” where all the products within the line have the same chemical composition except for a different amount of catalyst.

This document only specifies the performance of adhesives for use in an environment corresponding to the defined conditions.

The performance requirements of this document are applicable to the adhesives only, not to the manufactured timber products. This document does not cover the performance of adhesives for on-site gluing (except for factory-like conditions) or the production of wood-based panels, except solid wood panels, or modified and stabilized wood with considerably reduced swelling and shrinkage properties, e.g. acetylated wood, heat treated wood and polymer impregnated wood.

This document is primarily intended for use by adhesive manufacturers and for use in timber products bonded with adhesives, to assess or control the quality of adhesives. The requirements are applicable to the type testing of the adhesives. Production control activities are outside the scope of this document.

Adhesives meeting the requirements of this document are adequate for use in load-bearing timber products, provided that the bonding process has been carried out according to an appropriate product standard.

This document does not address the classification and use of adhesives in combination with the spraying of water before or during the bonding process; see informative Annex C of this document.

This does neither allow nor forbid the use of adhesives in combination with the spraying of water.

2 Normative references

3 Terms and definitions

4 Classification

5 Requirements

5.1 General

5.2 Bond strength in longitudinal tensile shear test

5.3 Resistance to delamination

5.4 Tensile strength perpendicular to the bond line after climatic treatment (acid damage test)

5.5 Effect of wood shrinkage on the shear strength

5.6 Static load test of multiple bond line specimens in compression shear

5.7 Creep deformation test at cyclic climate conditions with specimens loaded in bending shear

5.8 Long-term sustained load test at cyclic climate conditions with specimens loaded perpendicular to the bond line (“Glass house test”)

5.9 Delamination test on finger-jointed test pieces

6 Test methods

6.1 General

6.2 Determination of longitudinal tensile shear strength

6.3 Determination of resistance to delamination

6.4 Determination of tensile strength perpendicular to the bond line after climatic treatment (acid damage test)

6.5 Determination of the effect of wood shrinkage on the shear strength

6.6 Static load test of multiple bond line specimens in compression shear

6.7 Creep deformation test with specimens loaded in bending shear

6.8 Long-term sustained load test at cyclic climate conditions with specimens loaded perpendicular to the bond line (“Glass house test”)

6.9 Delamination test on finger-jointed test pieces

7 Working properties of the adhesive

7.1 General

7.2 Determination of initial viscosity under reference conditions

7.3 Determination of open assembly time under reference conditions

7.4 Determination of pressing time under reference conditions

8 Marking and labelling

Bibliography

BS EN 15425:2023

Adhesives. One component polyurethane (PUR) for load-bearing timber structures. Classification and performance requirements

Current, Under Review

Published:

28 Feb 2023