EN 927-6:2018

SLOVENSKI STANDARD
01-marec-2019
1DGRPHãþD
SIST EN 927-6:2007
%DUYHLQODNL3UHPD]LLQSUHPD]QLVLVWHPL]D]DãþLWROHVD]D]XQDQMRXSRUDER
GHO8PHWQRVWDUDQMHVIOXRUHVFHQWQLPL89VYHWLONDPLLQYRGR
Paints and varnishes - Coating materials and coating systems for exterior wood - Part 6:
Exposure of wood coatings to artificial weathering using fluorescent UV lamps and water
Beschichtungsstoffe - Beschichtungsstoffe und Beschichtungssysteme für Holz im
Außenbereich - Teil 6: Künstliche Bewitterung von Holzbeschichtungen mit
fluoreszierenden UV-Lampen und Wasser
Peintures et vernis - Produits de peinture et systèmes de peinture pour bois en extérieur
- Partie 6 : Vieillissement artificiel des revêtements pour bois par exposition à des
lampes UV fluorescentes et à de l'eau
Ta slovenski standard je istoveten z: EN 927-6:2018
ICS:
71.100.50 .HPLNDOLMH]D]DãþLWROHVD Wood-protecting chemicals
87.040 Barve in laki Paints and varnishes
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 927-6
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2018
EUROPÄISCHE NORM
ICS 87.040 Supersedes EN 927-6:2006
English Version
Paints and varnishes - Coating materials and coating
systems for exterior wood - Part 6: Exposure of wood
coatings to artificial weathering using fluorescent UV
lamps and water
Peintures et vernis - Produits de peinture et systèmes Beschichtungsstoffe - Beschichtungsstoffe und
de peinture pour bois en extérieur - Partie 6 : Beschichtungssysteme für Holz im Außenbereich - Teil
Vieillissement artificiel des revêtements pour bois par 6: Künstliche Bewitterung von Holzbeschichtungen mit
exposition à des lampes UV fluorescentes et à de l'eau fluoreszierenden UV-Lampen und Wasser
This European Standard was approved by CEN on 9 April 2018.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 927-6:2018 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Principle . 8
5 Apparatus . 8
5.1 Test chamber . 8
5.2 Lamps . 8
5.3 Device for wetting the test panels . 8
5.4 Black panel thermometer . 8
5.5 Irradiance control . 8
6 Test panels . 9
6.1 Wood . 9
6.2 Preparation and selection of wood panels . 10
6.3 Preparation of coated panels . 10
6.3.1 Wood conditioning . 10
6.3.2 Preparation of panels for the test coating . 10
6.3.3 Conditioning . 10
7 Procedure. 10
7.1 Examination before exposure . 10
7.2 Mounting the test panels . 11
7.3 Exposure . 11
7.3.1 Exposure cycle . 11
7.3.2 Sample rotation and maintenance . 11
7.3.3 Duration of test . 11
7.4 Examination of test panels . 11
8 Precision . 12
9 Expression of results and test report . 14
Annex A (normative) Details of the test methods . 15
A.1 Gloss and change of gloss . 15
A.2 Colour and colour change. 15
A.3 Blistering . 15
A.4 Flaking . 15
A.5 Cracking . 15
A.6 Chalking . 15
A.7 General appearance . 16
A.8 Adhesion . 16
Annex B (informative) Explanatory notes . 17
B.1 Explanation of exposure cycle . 17
B.2 Reproducibility . 17
B.3 Correlation to natural weathering . 17
B.4 Dependency on wood species and substrate . 17
B.5 Recommendation of periodical performance assessments . 17
Annex C (informative) Test for heartwood in pine . 18
Annex D (informative) Water treatment, devices for water purification . 19
Annex E (normative) Test for abnormally porous wood . 20
Annex F (informative) Alternative procedure for preparation and coating of panels . 21
Annex G (informative) Determination of adhesive strength of tape on test surface . 22
Bibliography . 23
European foreword
This document (EN 927-6:2018) 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 April 2019, and conflicting national standards shall be
withdrawn at the latest by April 2019.
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 927-6:2006.
The main technical changes are:
a) update of Normative references;
b) introduction of a new clause on precision (8);
c) new informative Annex G for the determination of the adhesive strength of the tape on test surface.
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.
The following Technical Specifications are published in this context:
CEN/TS 16358, Paints and varnishes — Coating materials and coating systems for exterior wood —
Assessment of air inclusions/microfoam in coating films
CEN/TS 16359, Paints and varnishes — Coating materials and coating systems for exterior wood —
Assessment of knot staining resistance of wood coatings
CEN/TS 16360, Paints and varnishes — Coating materials and coating systems for exterior wood —
Assessment of film extensibility by indentation of a coating on a wooden substrate
CEN/TS 16498, Paints and varnishes — Coating materials and coating systems for exterior wood —
Assessment of tannin staining
CEN/TS 16499, Paints and varnishes — Coating materials and coating systems for exterior wood —
Resistance to blocking of paints and varnishes on wood
CEN/TS 16700, Paints and varnishes — Coating materials and coating systems for exterior wood —
Assessment of resistance to impact of a coating on a wooden substrate
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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Introduction
Coatings from paints, varnishes and similar materials are weathered in a laboratory in order to
accelerate ageing processes (caused by temperature, wetness and irradiation) which occur during
natural weathering. Generally, a simple accelerating ratio between ageing during artificial and natural
weathering cannot be expected due to the influencing factors having different effects according to the
nature of the coating and substrate. Predictable relationships can only be expected if the effect of the
important parameters (spectral distribution of the irradiance in the photochemically relevant range,
temperature of the specimen, type of wetting, wetting cycle relative humidity) on the coating is known.
Moreover acceleration of the coating chemistry can cause alternative degradation pathways to be
followed. However, unlike natural weathering, testing in the laboratory can be controlled by the
operator and therefore the results are more repeatable and reproducible. This revision of EN 927-6
incorporates the results of a precision investigation that quantifies the capability of the test in terms of
repeatability and reproducibility.
1 Scope
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.
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 927-1, Paints and varnishes - Coating materials and coating systems for exterior wood - Part 1:
Classification and selection
EN ISO 2409, Paints and varnishes - Cross-cut test (ISO 2409)
EN ISO 2813, Paints and varnishes - Determination of gloss value at 20°, 60° and 85° (ISO 2813)
EN ISO 4628-1:2016, Paints and varnishes - Evaluation of degradation of coatings - Designation of
quantity and size of defects, and of intensity of uniform changes in appearance - Part 1: General
introduction and designation system (ISO 4628-1:2016)
EN ISO 4628-2, Paints and varnishes - Evaluation of degradation of coatings - Designation of quantity and
size of defects, and of intensity of uniform changes in appearance - Part 2: Assessment of degree of
blistering (ISO 4628-2)
EN ISO 4628-4, Paints and varnishes - Evaluation of degradation of coatings - Designation of quantity and
size of defects, and of intensity of uniform changes in appearance - Part 4: Assessment of degree of
cracking (ISO 4628-4)
EN ISO 4628-5, Paints and varnishes - Evaluation of degradation of coatings - Designation of quantity and
size of defects, and of intensity of uniform changes in appearance - Part 5: Assessment of degree of flaking
(ISO 4628-5)
EN ISO 4628-6, Paints and varnishes - Evaluation of degradation of coatings - Designation of quantity and
size of defects, and of intensity of uniform changes in appearance - Part 6: Assessment of degree of chalking
by tape method (ISO 4628-6)
EN ISO 16474-3, Paints and varnishes - Methods of exposure to laboratory light sources - Part 3:
Fluorescent UV lamps (ISO 16474-3)
ISO 554, Standard atmospheres for conditioning and/or testing — Specifications
ISO 18314-1, Analytical colorimetry — Part 1: Practical colour measurement
3 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 http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 Principle
Artificial weathering of coatings using fluorescent UV lamps, condensation or water spray is carried out
in order to produce a certain radiant exposure or mutually agreed total number of operation hours,
based on a given degree of a change in a property or properties. The properties of the exposed coatings
are compared with those of unexposed coatings, which are prepared from the same coating materials
under identical conditions or with coatings whose degradation properties are known.
Radiation, temperature and humidity all contribute to the ageing process. Therefore, the apparatus
specified in this standard simulates all three factors.
The results obtained by this method do not necessarily directly relate to the results obtained under
natural exposure conditions. The relationship between these results needs to be established before the
method can be used to predict performance.
The standard test substrate is pine sapwood with the back side of panels coated. However,
supplementary information on coating performance may be obtained by conducting optional tests on
additional wood species, on pine, modified or impregnated by industrial processes or without coating
the back side of the panels.
5 Apparatus
5.1 Test chamber
The test chamber consists of an enclosure made from corrosion-resistant material which houses the
lamps, a heated water tray, spray nozzles and test panel racks.
5.2 Lamps
A UV lamp emits UV light from a low pressure mercury arc. The required spectral distribution is
achieved by careful selection of the type of phosphor coating on the inner surface of the lamp and the
nature of the glass used in the construction of the tubes.
NOTE The principle construction details are described in EN ISO 16474-1.
The lamp shall be of type 1A (UVA 340) in accordance with EN ISO 16474-3 (peak emission at 340 nm).
5.3 Device for wetting the test panels
The test panels shall be wetted by condensation from the heated water tray and by spray. To prevent
spotting on to the test panels, water with a pH value between 5,0 and 7,5 and an electrical conductivity
of maximum 2 mS/m, measured at (25 ± 1) °C shall be used. See Annex D.
5.4 Black panel thermometer
Set the apparatus to operate at the specified parameters. The temperature shall be monitored by a
remote sensor attached to the black panel. The black panel thermometer shall be exposed to the same
exposure conditions as the specimens. Black panel thermometers shall be calibrated in accordance with
the manufacturer’s recommendations.
NOTE The construction of the black panel thermometer is described in ISO 16474-1.
5.5 Irradiance control
The irradiance at 340 nm shall be set to 0,89 W/(m nm) (see 7.3.1).
Apparatus equipped with an irradiance control system shall be calibrated in accordance with the
manufacturer’s recommendations.
Lamps within the apparatus without an irradiance control system need to be rotated and replaced in
accordance with the manufacturer’s recommendations to compensate for lamp ageing.
6 Test panels
6.1 Wood
The wood shall be Scots Pine (Pinus sylvestris) that has been selected free of knots, cracks and resinous
streaks, to be straight-grained and of normal growth rate (i.e. 3 to 8 annual rings per 10 mm). The
inclination of the growth rings to the face shall be 5° to 45° (see Figure 1).
The wood shall be free from blue stain and evidence of surface or bulk fungal infection. Abnormal
porosity (caused by bacterial attack) shall be avoided (see Annex E).
The panels shall be selected to give a sapwood test surface on the convex side
...