CEN/TC 139/WG 2 - Coating systems for wood

This document specifies a test method using water immersion test for assessing the bleeding of coloured wood extractives through a coating. Leachates of coated and uncoated wood are collected after the immersion procedure and their colour is compared. The colour of the coated wood before and after immersion tests is also compared. This document does not specify acceptance values for colour differences that can be tolerated and it is not applicable to staining caused by knots for which there is a different test method (see EN 927 7).
NOTE   The method has been developed for oak and chestnut wood and might be applicable for other wood substrates containing water soluble extractives.

This Technical Specification describes a test method to measure the ultraviolet (UV) and visible (VIS) spectral transmittance in the wavelength range from 280 nm to 700 nm of coatings for exterior wood. From the spectral transmittance the transmittance of UV, VIS and the UV plus VIS wavelength range can be calculated.
It is applicable to free coatings films or coatings applied on a UV-transparent substrate.

This document specifies a method for assessing the resistance of a coating system on wet wood to separation from the substrate by measuring the force necessary to detach or rupture the coating system by a normal tensile strain applied through an attached stud (dolly). Additional information is gained by noting the type and locus of failure. The force required for detachment will depend on several factors including the adhesion of the coating to the substrate and between intermediate coating layers. The procedure is not regarded as a direct means of measuring adhesion but an indicator of adhesive performance (adherence) under wet conditions.
A procedure for wetting the wood substrate is described. The test method is only suitable for wood and wood-based substrates.
For dry adhesion the test method can be carried out without wetting, in which case it will differ very little from EN ISO 4624.

This document specifies a method for determining the tensile properties of free coating films, specifically for exterior wood applications. Typical tensile properties of interest are the modulus of elasticity, the tensile strength and the elongation at break during stretching of a free coating film at constant test speed. The test methods specified in this document are applicable to coatings from which free films can be made.

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 defined and provide flexibility for different situations and can also provide a basis for certification.

This document specifies a test method for assessing the liquid water permeability of coating systems for exterior wood.

This document specifies a test method for assessing film extensibility by indentation of a coating on a defined and carefully selected wooden extensibility substrate for coatings on stable wood components in exterior use. The method is preferably be used on coatings that have not been exposed to weathering.

This document specifies a test method for assessing the discoloration of coating systems on wood due to wood extractives from knots. The discoloration is measured by colourimetry and the result is stated as the colour difference between the coated surface on the knot and the coated surface beside the knot.

This document specifies a laboratory test method for assessing microfoam in coating films on wood components. Samples are taken from finished wood components that are produced in a production plant, by craftsmen or a laboratory.
The test method can be used for further evaluation together with the performance specification given in EN 927-2. The amount and size of microfoam depends upon the coating material, the substrate and the application process and conditions.

This document specifies a test method for assessing the resistance of a coating to impact on a defined and carefully selected wooden substrate for coatings on wood components in exterior use.
The method is preferably used on coatings that have not been exposed to weathering. The method is suitable for use either as a means of comparing different coating systems or as a quality control test to ensure that a specified performance level is being achieved or maintained.

This document specifies a natural weathering test for exterior wood coating systems mainly intended for decoration and protection of planed and sawn wood.
The test provides a means of evaluating the performance of a wood coating system during outdoor exposure. It forms the basis for the performance specification in accordance with EN 927-2. It also facilitates the comparison of coating systems performance on different substrates including the wood species, or other wood modifications.

This document describes the method for assessing the resistance of paint coatings to separation from substrates when a double-X pattern is cut into the coating, penetrating through to the substrate and using a tape.
Where a measurement of adhesion is required, the method described in CEN/TS 927-9 may be used.
The double X-cut pattern has been especially designed for wood and wood like substrates to minimise the effects from the incisions and at the same time provide a coating segment enclosed by four cuts.

This document specifies a test method for determining, under specified optional conditions, whether a single-coat film or a multi-coat system of paints and varnishes on wood after a specified drying period is sufficiently dry to avoid damage when two painted surfaces or one painted surface and another surface are placed in contact under pressure and subsequently separated. The method is intended to simulate the conditions when painted articles come into contact which each other. In comparison to EN ISO 9117-2, the conditioning and parameters which influence the behaviour of wood coatings are more specific.
NOTE   In some countries, the test is called a "block or blocking resistance" test.

This part of EN 927 specifies a method for determining the resistance of wood coatings to artificial weathering performed in an apparatus equipped with fluorescent UV lamps, condensation and water spray devices.

This Technical Specification specifies a test method to evaluate the ability of coating materials to seal the end grain of wood against ingress of water.
This procedure is relevant for joinery or wood based cladding materials whose service life can depend on the control of water penetration through the coated end-grain.

This Technical Specification specifies a test method for assessing the discoloration of coatings on wood by tannin staining due to wood extractives. The method uses an extract from Merbau wood as an indicator. Bleeding of wood extractives is assessed at two specified stages firstly after coating application and secondly after cyclic climate exposure. A qualification of colour differences that can be attributed to three different causes, bleeding of extractives, low opacity of the coating film or general yellowing in climate exposure, is included. This document does not specify acceptance values for colour differences that can be tolerated and it is not applicable to staining caused by knots for which there is a different test method (e. g. CEN/TS 16359).

This European Standard specifies a system for the classification of coating systems and coating materials for exterior wood surfaces by categories of end use, appearance and exposure conditions. It also defines several components of a multi coat system (primer, undercoat, top coat, etc.).
It is applicable to all coating materials and coating systems intended for decoration and protection of exterior wood surfaces including those which contain biologically protective ingredients for the protection of coatings and at their surface (film preservation). The coating materials may include biologically active ingredients for the protection of the liquid coating material, for example during storage (in-can preservation) or to protect their interface with the wood (e.g. blue stain protection).
This European Standard is generally not applicable to wood preservatives. Wood preservatives may however be part of a coating system covered by this standard.
Guidance on selection criteria and the procedures for user's selection are given for information in Annex A.

This part of EN 927 specifies a test method for assessing the liquid water permeability of coating systems for exterior wood by measuring the water absorption of coated wood panels.
Results are expressed as water absorption in grams per square metre during a period of 72 h.

This part of EN 927 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 may 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 FprEN 927-2 are defined and provide flexibility for different situations and can also provide a basis for certification.

This Technical Specification specifies a test method for assessing film extensibility by indentation of a coating on a defined and carefully selected wooden extensibility substrate for coatings on stable wood components in exterior use. The method is preferably be used on coatings that have not been exposed to weathering.

This Technical Specification specifies a test method for assessing the discoloration of coating systems on wood due to wood extractives from knots. The discoloration is measured by colorimetry and the result is stated as the colour difference between the coated surface on the knot and the coated surface beside the knot.

This Technical Specification specifies a test method for assessing microfoam in coating films on stable wood components. Samples are taken from finished wood components that are produced in a production plant, by craftsmen or a laboratory.

This Technical Specification specifies a test method for assessing the resistance of a coating to impact on a defined and carefully selected wooden substrate for coatings on wood components in exterior use.
The method is preferably used on coatings that have not been exposed to weathering. The method is suitable for use either as a means of comparing different coating systems or as a quality control test to ensure that a specified performance level is being achieved or maintained.
The nature of the substrate will have a major effect on the results obtained in the test. Therefore use of any other substrate than the one specified should be clearly stated in the test report.

This European Standard specifies a natural weathering test for exterior wood coating systems mainly intended for decoration and protection of planed and sawn wood.
The test provides a means of evaluating the performance of a wood coating system during outdoor exposure. It forms the basis for the performance specification in accordance with EN 927-2.

This Technical Specification specifies a test method for determining, under standard conditions, whether a single-coat film or a multi-coat system of paints and varnishes on wood after a specified drying period is sufficiently dry to avoid damage when two painted surfaces or one painted surface and another surface are placed in contact under pressure and subsequently separated. The method is intended to simulate the conditions when painted articles come into contact which each other. In comparison to EN ISO 9117 2, the conditioning and parameters which influences the behaviour of wood coatings are more specific.
NOTE   In some countries, the test is called a “block or blocking resistance” test.

This Technical Specification specifies a method for assessing the resistance of a coating system on wet wood to separation from the substrate by measuring the force necessary to detach or rupture the coating system by a normal tensile strain applied through an attached stud (dolly). Additional information is gained by noting the type and locus of failure. The force required for detachment will depend on several factors including the adhesion of the coating to the substrate and between intermediate coating layers. The procedure is not regarded as a direct means of measuring adhesion but an indicator of adhesive performance (adherence) under wet conditions.
A procedure for wetting the wood substrate is described. The test method is only suitable for wood and wood based substrates.
For dry adhesion the test method is allowed to be carried out without wetting in which case it will differ very little from EN ISO 4624.

This part of EN 927 specifies a method for determining the resistance of wood coatings to artificial weathering performed in an apparatus equipped with fluorescent UV lamps, condensation and water spray devices.

This part of EN 927 addresses performance criteria for coating systems on exterior wood. Performance requirements are specified according to the categories of 'end use' and 'exposure conditions' (defined in EN 927-1) in terms of the results of natural weathering performance testing carried out in accordance with EN 927-3. A mandatory water permeability test in accordance with EN 927-5 is also specified. Additional optional tests are identified which may be used by suppliers to provide voluntary additional information, to a standardized format, on aspects of performance relevant to specific building components such as windows.

This European Standard specifies a system for the classification of coating systems for exterior wood surfaces by categories of end use, appearance and exposure conditions. It is applicable to all coating materials and coating systems intended for decoration and protection of exterior wood surfaces including those which contain biologically protective ingredients for the protection of coatings and at their interface with the wood surface (film preservation).

This part of EN 927 specifies a natural weathering test for exterior wood coating systems mainly intended for decoration and protection of planed and sawn wood.
The test provides a means of evaluating the performance of a wood coating system during outdoor exposure. It forms the basis for the performance specification in accordance with EN 927-2.

TC - Corrections in Annexes E and F

This part of EN 927 specifies a natural weathering test for exterior wood coating systems mainly intended for decoration and protection of planed and sawn wood. The test provides a means of evaluating the performance of a wood coating system during outdoor exposure. It
forms the basis for the performance specification in accordance with prENV 927-2:2000.

This part of EN 927 specifies a test method for assessing the liquid water permeability of coating systems for exterior wood by measuring the water absorption of coated wood panels. Results are expressed as water absorption in grams per square metre during a period of 72 h.

This part of EN 927 addresses performance criteria for coating systems on exterior wood. Performance requirements are specified according to the categories of 'end use' and 'exposure conditions' (defined in EN 927-1) in terms of the results of natural weathering performance testing carried out in accordance with EN 927-3:2000. A mandatory water permeability test in accordance with EN 927-5 : 2000 is also specified. Additional optional tests are identified which may be used by suppliers to provide voluntary additional information, to a standardized format, on aspects of performance relevant to specific building components such as windows.

This part of EN 927 specifies a test method for assessing the water-vapour permeability of coating systems for exterior wood by measuring the absorption and desorption of water vapour by coated wood panels. Results are expressed as the mass, in grams, of water gained and lost during two 14 day periods under specified conditions.