1、BS EN 927-5:2006ICS 87.040NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDPaints and varnishes Coating materialsand coating systems forexterior woodPart 5: Assessment of the liquid waterpermeabilityThis British Standardwas published under theauthority of the Sta
2、ndardsPolicy and StrategyCommittee on 31 October2008 BSI 2008ISBN 978 0 580 56079 8Amendments/corrigenda issued since publicationDate CommentsBS EN 927-5:2006National forewordThis British Standard is the UK implementation of . It supersedes BSEN 927-5:2000 which is withdrawn.The UK participation in
3、its preparation was entrusted to TechnicalCommittee STI/28, Paint systems for non-metallic substrates.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are res
4、ponsible for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.BS EN 927-5:2006EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 927-5 December 2006 ICS 87.040 Supersedes EN 927-5:2000 English Version Paints and varnishes - Coating materials a
5、nd coating systems for exterior wood - Part 5: Assessment of the liquid water permeability Peintures et vernis - Produits de peinture et systmes de peinture pour le bois en extrieur - Partie 5 : Dtermination de la permabilit leau liquide Beschichtungsstoffe - Beschichtungsstoffe und Beschichtungssys
6、teme fr Holz im Auenbereich - Teil 5: Beurteilung der Wasserdurchlssigkeit This European Standard was approved by CEN on 4 May 2006. 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 sta
7、ndard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any othe
8、r language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland,
9、France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITE
10、E FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 927-5:2006: EBS EN 927-5:2006EN 927-5:2006 (E) 2 Contents Page Foreword3 Introduction .4 1 Scope 5 2 Normative
11、 references 5 3 Terms and definitions .5 4 Principle5 5 Test panels .5 6 Apparatus .9 7 Procedure .9 8 Calculation and expression of results.10 9 Precision.10 10 Test report 11 Annex A (informative) Interpretation of test results and further calculations 12 Annex B (informative) Suggested form for s
12、pecifying application parameters.13 Bibliography 18 BS EN 927-5:2006EN 927-5:2006 (E) 3 Foreword This document (EN 927-5:2006) 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 na
13、tional standard, either by publication of an identical text or by endorsement, at the latest by June 2007, and conflicting national standards shall be withdrawn at the latest by June 2007. This document supersedes EN 927-5:2000. EN 927 consists of the following parts under the general title: Paints
14、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 fluorescen
15、t UV lamps and water According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Irela
16、nd, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. BS EN 927-5:2006EN 927-5:2006 (E) 4 Introduction The treatment of exterior wood surfaces has both aesthetic and protective functions. A
17、vital purpose of a coating system is to protect the wood against aesthetic deterioration (e.g. blue stain attack) and dimensional changes. Because such attacks are mainly caused by high moisture contents in the wood, a knowledge of the relative water permeability properties of coating materials appl
18、ied to exterior wood is helpful in selecting products for particular end-use applications, as described in EN 927-1. BS EN 927-5:2006EN 927-5:2006 (E) 5 1 Scope This part of EN 927 specifies a test method for assessing the liquid water permeability of coating systems for exterior wood. 2 Normative r
19、eferences The following referenced documents are indispensable for the application 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. prEN ISO 2808:2004, Paints and varnishe
20、s Determination of film thickness (ISO/DIS 2808:2004) ISO 554, Standard atmospheres for conditioning and/or testing Specifications 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 water absorption ability of a coated or uncoated wood panel to
21、absorb water from liquid or vapour 3.2 water permeability ability of a coating system to allow the transmission of water as liquid or vapour EN 927-1 3.3 stable mass mass achieved when the difference between two subsequent weighings within 24 h does not exceed 0,2 % 4 Principle Water permeability is
22、 assessed by measuring the water uptake over a 72 h period of a coated test panel exposed to liquid water. The coating under test is applied to the face of a defined test panel where the remaining face and sides are carefully sealed using a sealer of a defined mandatory low permeability. Results are
23、 expressed as water absorption of coated wood panels in grams per square metre test surface per 72h. 5 Test panels 5.1 Wood The wood shall be spruce (Picea abies) that has been selected to be free from knots and cracks, to be straight-grained and of normal growth rate (i.e. between 3 and 8 annual ri
24、ngs per 10 mm). The inclination of the growth rings to the test face shall be (45 10). See Figure 1. BS EN 927-5:2006EN 927-5:2006 (E) 6 The wood shall be free from blue stain and evidence of surface or bulk infection. Abnormal porosity (caused by bacterial attack) shall be avoided. Abnormally porou
25、s wood can be detected qualitatively by the rapid absorption of a drop of propan-2-ol (isopropanol) applied to the surface; the drop should not be absorbed in less than 30 s by normal wood. The test should be carried out at not less than six places, widely separated on the rear face of the test pane
26、l. The density of the wood shall be between 0,4 g/cm and 0,5 g/cm when measured at an equilibrium moisture content of approximately 12 %. The measured density shall be recorded. Condition the wood prior to conversion into test panels in accordance with ISO 554 at (20 2) C and a relative humidity of
27、(65 5) %. Dimensions in millimetres Key 1 Front of panel (test face) a Min. 3, max. 8 growth rings/10 mm. Angle of growth rings to test face min. 35, max. 55. Figure 1 Selection of wood 5.2 Preparation and selection of test panels Convert the conditioned wood into panels (340 2) mm (70 2) mm (20 2)
28、mm in size. It is intended that after coating one panel 150 mm in length will be cut from each end of this 340 mm long panel. This will leave an off-cut Ccapproximately 40 mm in length from the middle of the panel, to be used in due course for the determination of film thickness (see 5.3.5 and Figur
29、e 2). The panels shall be planed all round to a smooth and uniform finish. Any panels showing surface splitting shall be rejected. BS EN 927-5:2006EN 927-5:2006 (E) 7 5.3 Preparation of coated and uncoated panels 5.3.1 Wood conditioning Prior to coating, condition the panels to constant mass in acco
30、rdance with ISO 554 at (20 2) C and a relative humidity of (65 5) %. Panels shall be weighed at intervals of not less than one day until they have reached a stable mass (see 3.3). 5.3.2 Panel selection Select three panels for each of the coatings to be tested. Select also three panels for testing th
31、e sealer product; this set of panels will serve as sealed controls (see Figure 2). Mark each panel to identify the test face as that convex to the annual rings. Dimensions in millimetres Figure 2 Cutting of test panels BS EN 927-5:2006EN 927-5:2006 (E) 8 5.3.3 Coating application Coating systems sha
32、ll be applied according to the manufacturers specifications. Apply each test coating system to the test face only (convex side of the panels). Each coating system under test requires 3 test panels (340 mm 70 mm 20 mm). When the coating systems have dried, cut a test panel 150 mm in length from both
33、ends of each long panel (see Figure 2). The three small coated off-cuts Ccare used for the determination of film thickness. Three additional panels are required to check the test face with the selected sealer. This sealer and the number of layers should be identical with the later on used sealer for
34、 sealing the test panels (150 mm 70 mm 20 mm). The liquid water permeability of the sealer shall not exceed 30 g/m in 72 h (see Figure 2). Additional information is given in Annex B. 5.3.4 Sealing and conditioning Panels shall be sealed in the same way whether they are applied for test coatings or c
35、ontrol of sealer. Seal the sides, end-grains and reverse faces of the panels against water entry using at least two coats of a flexible moisture-impermeable coating, for example a solvent-free epoxy or polyurethane paint. The sealer shall cover the edges completely and overlap the test face by 2 mm
36、(see Figure 3). Apply the sealer to the end grain so many times that a closed and uniform film is obtained. Dimensions in millimetres Key 1 Test face. 2 2 mm l Length of the test face w Width of the test face Figure 3 Sealing of panels After sealing, condition the panels in the controlled environmen
37、t (see 5.3.1) until constant mass is achieved (for typically 7 to 28 days). After drying of the sealer measure and record the actual test area of each panel (see Figure 3). BS EN 927-5:2006EN 927-5:2006 (E) 9 5.3.5 Dry film thickness Determine the dry film thickness of the coating on the off-cuts (s
38、ee Figure 2) of the test panels. Remove one small chip of coated wood from each of the off-cuts and examine by microscopy in accordance with prEN ISO 2808:2004, method 6A. Make 5 measurements on each chip and calculate and record the mean value in micrometres. The dry film thickness is defined as th
39、e thickness of the layer on (above) the wood surface. Systems may penetrate the wood material to some extent, but this part is not included in the determination. 6 Apparatus 6.1 Microscope for measurement of dry film thickness in accordance with prEN ISO 2808:2004, method 6A. 6.2 Conditioning room,
40、of appropriate size, controlled at a temperature of (20 2) C and a relative humidity of (65 5) %, in accordance with ISO 554. 6.3 Container for deionized water, of size sufficient to hold the all the panels under test. 6.4 Balance, capable of weighing to the nearest 0,01 g. 7 Procedure 7.1 Pre-condi
41、tioning It is known that the water permeability of some types of coating can change markedly during a relatively short period of exposure to water. For such coatings the values of water permeability obtained during a short period of contact with water might not be representative of those obtained du
42、ring long-term service. For this reason all panels shall be subjected to a leaching procedure before commencement of the absorption cycle. This procedure shall be carried out twice as follows: 24 h floating face down in deionized water, such that the test face is fully submerged; 3 h drying at (20 2
43、) C and a relative humidity of (65 5) % in accordance with ISO 554; 3 h drying at 50 C; 18 h drying at (20 2) C and a relative humidity of (65 5) % in accordance with ISO 554. All panels shall be handled together. After preconditioning, the test panels shall be conditioned by returning them to the c
44、ontrolled environment (see 6.2) in accordance with ISO 554 at (20 2) C and a relative humidity of (65 5) %, until a stable mass is achieved once more. 7.2 Absorption cycle Weigh the test panels to the nearest 0,01 g and record the initial mass (m0). Fill the container (6.3) with deionized water and
45、place it in the conditioning room (6.2). The water shall have reached stable temperature in the conditioned room, i.e. (20 2) C. Float the test panels face down on the surface of the water ensuring that the whole of the test face is fully wetted. BS EN 927-5:2006EN 927-5:2006 (E) 10 After 72 h remov
46、e the test panels from the water, blot lightly to remove any water droplets and weigh. Record the elapsed time and mass (m1). All handling of the panels shall be carried out in the conditioning room (6.2). 7.3 Optional testing of weathered panels If required, coatings may be subjected to a weatherin
47、g test before or after measurement of liquid water permeability. 8 Calculation and expression of results At the end of the test calculate the water uptake m1- m0, in grams, for each test panel. Calculate the water absorption per square metre of test surface for the test panels by dividing the water
48、uptake by the measured test area of each of the test panels. Finally calculate the mean value of the individual measurements. Mean value, standard deviation and coefficient of variation shall be stated in the test report. If the water absorption of the test panels with the sealer exceeds 30g/m2in 72
49、 h the test is not valid. 9 Precision 9.1 Repeatability (r) The repeatability r is the value below which the absolute difference between two single test results, each mean of duplicates, can be expected to lie when this method is used repeatability conditions. In this case, the test results are obtained on identical material by one operator in one laboratory within a short interval if time using the standardized test method. In this standard, r is 9,1 (32,7 % relative to the mean
