National foreword

This British Standard is the UK implementation of EN 927‑2:2022. It supersedes BS EN 927‑2:2014, which is withdrawn.

The UK participation in its preparation was entrusted to Technical Committee STI/28, Paint systems for non-metallic substrates.

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 31 December 2022.

This European Standard was approved by CEN on 16 October 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 927‑2:2022) has been prepared by Technical Committee CEN/TC 139 “Paints and varnishes”, the secretariat of which is held by DIN.

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 May 2023, and conflicting national standards shall be withdrawn at the latest by May 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 927‑2:2014.

The following significant technical changes have been made with respect to EN 927‑2:2014:

test profiles for the three main end-use categories (as specified in EN 927‑1) have been updated to include additional test methods;
Existing test methods (5.2) have been updated to include additional methods and 5.3 (Test methods in preparation) has been deleted.

EN 927 consists of the following parts under the general title Paints and varnishes — Coating materials and coating systems for exterior wood,

Part 1: Classification and selection
Part 2: Performance specification
Part 3: Natural weathering test
Part 5: Assessment of the liquid water permeability
Part 6: Exposure of wood coatings to artificial weathering using fluorescent UV lamps and water
Part 7: Assessment of knot staining resistance of wood coatings
Part 8: Determination of the adherence of paint on wood by means of a double X-cut test 1
Part 9: Determination of pull-off strength after water exposure¹
Part 10: Resistance to blocking of paints and varnishes on wood
Part 11: Assessment of air inclusions/microfoam in coating films
Part 12: Ultraviolet and visible radiation transmittance
Part 13: Assessment of resistance to impact of a coating on a wooden substrate
Part 14: Determination of tensile properties of coating films

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 number of parts of EN 927. EN 927‑1 addresses the issue of terminology for the wide variety of exterior coatings for wood that are now available. EN 927‑1 also provides a framework for communicating information on the suitability of a coating for particular specific end-use categories. Improved communication is beneficial in the removal of technical barriers to trade. However, there remains the problem of comparing products tested, or likely to be exposed, in different climatic regions, and the relevance of tests for different categories of end-use. This document addresses these issues and sets a limited number of mandatory performance criteria combined with optional tests that can provide additional information to a standardized format.

1 Scope

This document addresses performance criteria for coating systems on exterior wood. Performance requirements are specified according to three categories of end use (defined in EN 927‑1) in terms of two mandatory tests, namely natural weathering performance testing carried out in accordance with EN 927‑3, and water permeability in accordance with EN 927‑5. Additional optional tests (non-mandatory) are tabled which can be used by suppliers, or for specification purposes, to provide additional information, to a standardized format, on aspects of performance relevant to specific situations. The majority of test methods are drawn from EN 927 (all parts), but where relevant additional tests from other national and international sources are used.

Requirements for claiming conformity with this document are specified and provide flexibility for different situations and can also provide a basis for certification.

2 Normative references

3 Terms and definitions

4 Performance tests – Testing profiles

5 Test overview

5.1 Natural weathering

5.2 Existing test methods

6 Summary of test methods and reporting convention

7 Expression of results and claiming conformity – Scope and reporting convention

BS EN 927-2:2022

Paints and varnishes. Coating materials and coating systems for exterior wood - Performance specification

Current

Published:

31 Jul 2025