1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 927-3:2012Paints and varnishes Coatingmaterials and coating systemsfor exterior woodPart 3: Natural weathering testBS EN 927-3:2012 BRITISH STANDARDNational forewordThis Br
2、itish Standard is the UK implementation of EN 927-3:2012. Itsupersedes BS EN 927-3:2006 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee STI/28, Paint systems for non-metallic substrates.A list of organizations represented on this committee can beobtaine
3、d on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 73650 6ICS 87.040Compliance with a Brit
4、ish Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 July 2012.Amendments issued since publicationDate Text affectedBS EN 927-3:2012EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 92
5、7-3 July 2012 ICS 87.040 Supersedes EN 927-3:2006English Version Paints and varnishes - Coating materials and coating systems for exterior wood - Part 3: Natural weathering test Peintures et vernis - Produits de peinture et systmes de peinture pour bois en extrieur - Partie 3: Essais de vieillisseme
6、nt naturel Beschichtungsstoffe - Beschichtungsstoffe und Beschichtungssysteme fr Holz im Auenbereich - Teil 3: Freibewitterung This European Standard was approved by CEN on 9 June 2012. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for givin
7、g 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 offic
8、ial 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
9、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, Slovakia, Slovenia, Spain, S
10、weden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2012 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN nationa
11、l Members. Ref. No. EN 927-3:2012: EBS EN 927-3:2012EN 927-3:2012 (E) 2 Contents Page Foreword 41 Scope 52 Normative references 53 Principle 64 Apparatus and materials .65 Sampling .66 Test panels .76.1 Wood .76.2 Preparation and selection of wood panels .86.3 Preparation of coated panels .86.3.1 Wo
12、od conditioning 86.3.2 Preparation of panels for the test coating 86.3.3 Preparation of panels for the Internal Comparison Product (ICP) .86.3.4 Sealing and ageing 86.3.5 Thickness of the coating .97 Procedure 107.1 General . 107.2 Examination before exposure . 107.3 Exposure 107.4 Examination after
13、 exposure . 107.4.1 Examination on the exposure racks . 107.4.2 Laboratory examination of unwashed panels . 107.4.3 Laboratory examination of washed panels 118 Precision data . 119 Expression of results and test report . 11Annex A (normative) Internal Comparison Product (ICP) alkyd stain 12Annex B (
14、normative) Details of test methods . 14B.1 Gloss and change of gloss 14B.2 Colour and colour change . 14B.3 Blistering . 14B.4 Flaking . 14B.5 Mould growth 14B.6 Cracking . 15B.7 Chalking . 15B.8 General appearance . 15B.9 Adhesion 15B.9.1 General . 15B.9.2 Apparatus 15B.9.3 Procedure 15B.10 Test fo
15、r abnormally porous wood . 16B.11 Test for heartwood in pine . 16Annex C (normative) Assessment requirements for panels of test coatings and ICP . 17Annex D (informative) Suggested format for a test report . 18Annex E (informative) Optional tests including variations to standard weathering test proc
16、edure to obtain additional information on coating performance . 21BS EN 927-3:2012EN 927-3:2012 (E) 3 E.1 Principle 21E.2 Tests on alternative wood substrates . 21E.3 Tests with water trap . 21E.3.1 Apparatus and materials. 21E.3.2 Preparation . 22E.3.3 Panel assessment . 22E.4 Tests with back seali
17、ng of the panels . 23Annex F (informative) Explanatory notes . 24F.1 Natural weathering test . 24F.2 Validity of test reports . 24F.2.1 System 24F.2.2 Climate and region 24Annex G (informative) Precision data . 25Bibliography 26BS EN 927-3:2012EN 927-3:2012 (E) 4 Foreword This document (EN 927-3:201
18、2) 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 January 2013, and conflictin
19、g national standards shall be withdrawn at the latest by January 2013. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document s
20、upersedes EN 927-3:2006. The main technical changes are: a) Precision data were added in an informative Annex G; b) Using the multi-blade cutting tool for cross-cut test is allowed. EN 927 consists of the following parts under the general title: Paints and varnishes Coating materials and coating sys
21、tems 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. According to the CEN
22、/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, Hungar
23、y, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 927-3:2012EN 927-3:2012 (E) 5 1 Scope This European Standard specifies a natural weathering test for
24、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. 2 Normative
25、 references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) appl
26、ies. EN ISO 1513, Paints and varnishes Examination and preparation of test samples (ISO 1513) EN ISO 2409, Paints and varnishes Cross-cut test (ISO 2409) EN ISO 2431, Paints and varnishes Determination of flow time by use of flow cups (ISO 2431) EN ISO 2808:2007, Paints and varnishes Determination o
27、f film thickness (ISO 2808:2007) EN ISO 2810, Paints and varnishes Natural weathering of coatings Exposure and assessment (ISO 2810) EN ISO 2813, Paints and varnishes Determination of specular gloss of non-metallic paint films at 20, 60 and 85 (ISO 2813) EN ISO 4628-1:2003, Paints and varnishes Eval
28、uation 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 4628-1:2003) EN ISO 4628-2, Paints and varnishes Evaluation of degradation of coatings Designation of quantity and
29、 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:
30、 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 varni
31、shes 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 11664-4, Colorimetry Part 4: CIE 1976 L*a*b* Colour space (ISO 11664-4) EN ISO 15528,
32、Paints, varnishes and raw materials for paints and varnishes Sampling (ISO 15528) ISO 554, Standard atmospheres for conditioning and/or testing Specifications BS EN 927-3:2012EN 927-3:2012 (E) 6 3 Principle The resistance to natural weathering of the coating system under test, applied to a wood subs
33、trate, is assessed. Durability is evaluated by determining the changes in decorative and protective properties of coatings after 12 months of exposure. The standard test substrate selected was Pinus sylvestris (European redwood or Scots pine, subsequently referred to as pine) in order to obtain rele
34、vant results more rapidly. The sapwood, which is usually present in joinery timber, was chosen for use instead of heartwood because paint failure is more evident on the former. Differences in quality of wood, and in the weather and site conditions, are recognised and allowed for in the method by com
35、paring the test with a reference system. The composition of the reference system (designated as “Internal Comparison Product“ or “ICP“) is specified in Annex A. The standard test substrate is pine sapwood with the rear side of panels untreated. However, supplementary information on coating performan
36、ce may be obtained by conducting optional tests on additional wood species, on pine modified or impregnated by industrial processes, by using a pine panel containing a water trap in its exposed face, or by coating the rear side of the panels. Optional tests are described in Annex E. It is emphasised
37、 that they can serve only to provide additional information. 4 Apparatus and materials 4.1 Exposure racks, inclined at an angle of 45 to the horizontal, on which the specimens are facing towards the equator in accordance with EN ISO 2810. 4.2 Glossmeter, for the measurement of specular gloss in acco
38、rdance with EN ISO 2813, at 60 geometry. 4.3 Tristimulus colorimeter or spectrophotometer, for the measurement of colour and calculation of colour difference in CIELAB colour coordinates in accordance with EN ISO 11664-4. 4.4 Tape and cutting tool, for the assessment of adhesion in accordance with E
39、N ISO 2409. 4.5 Microscope, with a magnification of 10 for the assessment of surface defects. 4.6 Microscope, for measurement of film thickness in accordance with ISO 2808:2007, method 6A. 4.7 Self-adhesive, transparent tape, in accordance with EN ISO 4628-6 for the assessment of chalking. 4.8 Clima
40、te chamber. 5 Sampling Take a representative sample of the product tested or of each product in the case of a multi-coat system, as described in EN ISO 15528. Examine and prepare each sample for testing as described in EN ISO 1513. BS EN 927-3:2012EN 927-3:2012 (E) 7 6 Test panels 6.1 Wood The wood
41、shall be pine that has been selected to be free from knots, cracks and resinous streaks and 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 an
42、d evidence of surface or bulk fungal infection. Abnormal porosity (caused by bacterial attack) shall be avoided (see Annex B, Clause B.10). The wood shall be conditioned at (20 2) C and a relative humidity of (65 5) % (in accordance with ISO 554) to an equilibrium moisture content of (13 2) %. a) b)
43、 c) d) Key a) Example of a panel with no heartwood (if present) closer than 10 mm to the test surface fulfilling the requirement for growth ring orientation (5 to 45) at the front side. b) This panel does not meet the specification because the heartwood is too close to the front side. c) This panel
44、does not meet the specification because the growth ring orientation is not within the 5 to 45 band. The growth rings incline -10 at the left of the panel and 30 at the right. Consequently a part of the surface contains tangentially cut wood surface (growth ring inclination 0), with considerable risk
45、 of crack formation. d) This panel does not meet the specification because the growth ring orientation is not within the 5 to 45 band. The growth rings incline 45 at the left of the panel and 70 at the right. NOTE The top side of panels is the exposed side; the bottom is the rear face. Figure 1 Cros
46、s section of panels BS EN 927-3:2012EN 927-3:2012 (E) 8 6.2 Preparation and selection of wood panels The panels shall be cut from boards planed all round and shall be nominally (375 2) mm (78 3) mm and (20 2) mm thick. For details of panel preparation see Figure 2. The panels shall be planed to a sm
47、ooth and uniform finish. In order to avoid aged wood surface, the panels shall be hand sanded (mesh 150) immediately before coating. Rounding of edges is not permitted. The panels shall be selected to give a sapwood test surface on the convex side of the growth rings, with any heartwood confined to
48、a zone no closer than 10 mm from the front side. Heartwood shall be checked with the reagent described in B.11, at both ends of each panel. Any panels showing surface splitting shall be rejected. Where the presence of some minor defects in the test area is unavoidable, their position should be noted
49、 and their influence excluded during assessment of coating performance. 6.3 Preparation of coated panels 6.3.1 Wood conditioning Prior to coating, condition the panels at (20 2) C and a relative humidity of (65 5) % until constant mass in accordance with ISO 554. Keep the panels under the same conditions during drying of the coating system and during subsequent
