1、BSI Standards Publication PD CEN/TS 16700:2014 Paints and varnishes Coating materials and coating systems for exterior wood Assessment of resistance to impact of a coating on a wooden substratePD CEN/TS 16700:2014 PUBLISHED DOCUMENT National foreword This Published Document is the UK implementation
2、of CEN/TS 16700:2014. 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 secretary. This publication does not purport to include all th
3、e necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2014. Published by BSI Standards Limited 2014 ISBN 978 0 580 84745 5 ICS 87.040 Compliance with a British Standard cannot confer immunity from legal obligations. This Published
4、Document was published under the authority of the Standards Policy and Strategy Committee on 31 August 2014. Amendments issued since publication Date Text affectedPD CEN/TS 16700:2014 TECHNICAL SPECIFICATION SPCIFICATION TECHNIQUE TECHNISCHE SPEZIFIKATIONCEN/TS 16700 August 2014 ICS 87.040 English V
5、ersion Paints and varnishes - Coating materials and coating systems for exterior wood - Assessment of resistance to impact of a coating on a wooden substrate Peintures et vernis - Produits de peinture et systmes de revtements pour le bois en extrieur - Evaluation de la rsistance au choc dun revtemen
6、t sur un subjectile en bois Beschichtungsstoffe - Beschichtungsstoffe und Beschichtungssysteme fr Holz im Auenbereich - Beurteilung der Schlagfestigkeit einer Beschichtung auf Holzusubstrat This Technical Specification (CEN/TS) was approved by CEN on 17 May 2014 for provisional application. The peri
7、od of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard. CEN members are required to announce the existence of this CEN/
8、TS in the same way as for an EN and to make the CEN/TS available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached
9、. 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, Pola
10、nd, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2014 CEN All rights of exploitation
11、in any form and by any means reserved worldwide for CEN national Members. Ref. No. CEN/TS 16700:2014 EPD CEN/TS 16700:2014 CEN/TS 16700:2014 (E) 2 Contents PageForeword3 Introduction .4 1 Scope 5 2 Normative references 5 3 Terms and definitions .5 4 Principle6 5 Apparatus and materials.6 6 Procedure
12、 .7 6.1 Wood panels.7 6.2 Coating application7 6.3 Assessment of resistance to impact .7 6.3.1 General7 6.3.2 Impact test 8 6.3.3 Examination of test panel .8 6.3.4 Assessment of results 8 7 Test report . 10 Bibliography . 11 PD CEN/TS 16700:2014 CEN/TS 16700:2014 (E) 3 Foreword This document (CEN/T
13、S 16700:2014) has been prepared by Technical Committee CEN/TC 139 “Paints and Varnishes”, the secretariat of which is held by DIN. 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 fo
14、r identifying any or all such patent rights. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland,
15、Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.PD CEN/TS 16700:2014 CEN/TS 16700:2014
16、 (E) 4 Introduction During the use coated wood surfaces are exposed to various impacts. A suitable resistance of a coating on wood to impact is of importance to keep the substrate further protected with intact coating without cracks or flakes. The simple method described in this document provides qu
17、ick information if a coating on wood is capable to withstand impacts without cracks or not. A similar method exists in ISO 4211-4 for furniture surfaces in interior use but in the present document the procedure is adopted and description of a carefully selected substrate is added to enable testing o
18、f coating materials and coating systems for exterior wood. The method should preferably be used on coatings that have not been exposed to weathering but it may also be applied after ageing of the coating or under different climatic conditions to gain additional experience.PD CEN/TS 16700:2014 CEN/TS
19、 16700:2014 (E) 5 1 Scope 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 expose
20、d 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
21、. Therefore use of any other substrate than the one specified should be clearly stated in the test report. 2 Normative 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 editio
22、n cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 554, Standard atmospheres for conditioning and/or testing Specifications ISO 3131, Wood Determination of density for physical and mechanical tests 3 Terms and definitions Fo
23、r the purposes of this document, the following terms and definitions apply. 3.1 coating layer formed from a single or multiple application of a coating material to a substrate SOURCE: FprEN ISO 4618:2014, 2.50.1 3.2 impact resistance ability of a coating to resist deformation from a sudden blow with
24、out damage 3.3 cracking rupturing of a dry film or coat SOURCE: FprEN ISO 4618:2014, 2.65, modified Notes have been left out 3.4 flaking detachment of small parts of a coating due to a loss of adhesion SOURCE: FprEN ISO 4618:2014, 2.114 PD CEN/TS 16700:2014 CEN/TS 16700:2014 (E) 6 4 Principle A cyli
25、ndrical steel weight is dropped from specified heights through a vertically-mounted guide onto a steel ball of specified diameter and hardness positioned on the test panel. The degree of damage to the test area is assessed by reference to a descriptive numerical rating code. 5 Apparatus and material
26、s 5.1 Horizontal base which provides rigid support for the test panel. 5.2 Vertically-mounted guide tube with an inside diameter of (40 5) mm (1 in Figure 1). A (10 0,5) mm thick disc with a centre hole of diameter (14,25 0,25) mm for the ball (5.4) shall be attached to the bottom end of the guide t
27、ube. Key 1 vertically-mounted guide tube 2 cylindrical steel weight 3 steel ball 4 test panel Figure 1 Impact on surface 5.3 Cylindrical steel weight (2 in Figure 1) with a mass of (500 5) g and a diameter that is approximately 1 mm less than the inside diameter of the guide tube. This weight shall
28、be made of softer alloy than the ball, so that it will not make indentations on the ball. Provision shall be made for the weight to be raised and lowered. 5.4 Steel ball (3 in Figure 1) with a diameter of 14 mm and Rockwell hardness of 60 HRC to 66 HRC, (see EN ISO 6508-1), a rolling bearing ball fo
29、r example, (see ISO 3290-1). 5.5 Microscope (magnifier) with a magnification of at least 10 for the assessment of surface defects.PD CEN/TS 16700:2014 CEN/TS 16700:2014 (E) 7 6 Procedure 6.1 Wood panels Boards of Norway spruce (Picea abies L. Karst) are selected with normal growth rate (i.e. 3 annua
30、l rings to 8 annual rings per 10 mm), a density between 0,4 g/cm 3 and 0,5 g/cm 3 (measured after conditioning) and straight grain. 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 EN 927-3:2
31、012, B.10). From these boards panels with the dimensions min. 170 mm min. 70 mm (20 2) mm free from knots, cracks and resinous streaks are produced so that the inclination of the growth rings to the test surface is 60 to 90. The panels shall be planed to a smooth and uniform finish. In order to avoi
32、d aged wood surface, the panels shall be hand sanded (mesh 150) immediately before coating. 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) %. After conditioning wood density is determined according
33、 to ISO 3131. 6.2 Coating application For each system, select three panels on a random basis from the available supply. Apply the coating system to the front side of one panel using the method specified by the manufacturer to give a wet film thickness corresponding to the mean value 20 % of the manu
34、facturers recommended spreading rate. Record the quantity of coating applied. The values should be stated preferably in grams per square metre, but may also be expressed as wet film thickness (in micrometres). After coating application, age the panels for 21 days in the controlled environment at (20
35、 2) C and a relative humidity of (65 5) % in accordance with ISO 554. 6.3 Assessment of resistance to impact 6.3.1 General No impact point shall be less than 15 mm from any edge of the test panel. The centres of impact points shall not be less than 15 mm apart. lf the grid pattern method detailed in
36、 6.3.2 is to be used, then eight lines spaced at least 15 mm apart shall be marked out on the surface that is to be tested. The lines shall be perpendicular to the direction of grain. Three impact points spaced at least 15 mm apart shall be marked off along each line (see Figure 2). Key a direction
37、of grain Figure 2 Impact points on surfacePD CEN/TS 16700:2014 CEN/TS 16700:2014 (E) 8 The test panel shall be placed in a stable position on the horizontal base (5.1) in such way that all impact points are inside the area covered by the base. The tests should be carried out at an ambient temperatur
38、e of (23 2) C, and at a relative humidity of (50 5) %. 6.3.2 Impact test On each panel make six impacts from each of the following dropping heights: 10 mm; 25 mm; 50 mm and 100 mm. The dropping height, which shall be measured within 0,5 mm, is the distance from the top of the ball to the bottom surf
39、ace of the weight. Either make a random selection of impact sites, making provision to identify the dropping height for each site adequately, or preferably use the grid pattern described in 6.3.1 making three impacts on each numbered line with dropping heights as follows: on line 1 from a dropping h
40、eight of 10 mm; on line 2 from a dropping height of 25 mm; on line 3 from a dropping height of 50 mm; on line 4 from a dropping height of 100 mm; on line 5 from a dropping height of 10 mm; on line 6 from a dropping height of 25 mm; on line 7 from a dropping height of 50 mm; on line 8 from a dropping
41、 height of 100 mm. For each test, position the guide tube (5.2) on the test area with the ball (5.4) in direct contact with the surface. Drop the cylindrical weight (5.3) once from the specified height onto the ball. After each test, the ball should be examined for possible deformation and if necess
42、ary replaced by an undamaged ball. After completion of the test, the application of penetrating stain or other suitable marker (like whiteboard marker of suitable colour) to the test area can assist with the identification of surface cracks. After few seconds after marking, carefully wipe the impact
43、 mark with the soft paper towel to remove residue of the marker. 6.3.3 Examination of test panel Carefully examine the test area under magnification and good direct light using the following procedure. Keeping the test area directly under the light, rock the panel or the light, so that the angle bet
44、ween the direction of the light and the plane of the panel varies between 0 and 30. During the rocking movement, examine the test area using the microscope (5.5). Turn the test area of the panel through 90 and repeat the procedure. 6.3.4 Assessment of results Rate the test areas according to the des
45、criptive numerical rating code in the Table 1 (see also Figure 3).PD CEN/TS 16700:2014 CEN/TS 16700:2014 (E) 9 Table 1 Descriptive numerical rating code Rating Description 0 No visible changes (no damage). 1 No cracks in the surface but the impact mark is visible when light from the source is reflec
46、ted from the surface at or very near the test point, and the reflected light strikes the observers eye. 2 Slight cracking at the surface, usually one or two circular cracks within the impact mark. a 3 Moderate to heavy cracking limited to the impact mark. b 4 Cracks which extend outside the impact m
47、ark and/or flaking of the coating. a The cracks need not form full circles; they can form circle arcs or straight lines in the direction of the grain. Arcs usually form across the grain. In such cases, damage is estimated on the basis of the number of cracks or circle arcs inside the impact mark. St
48、raight cracks in direction of the grain of the wood substrate should not be ignored. b A certain amount of care should be taken when deciding whether cracks lie inside or outside the impact mark, since its boundaries are often obscure. Key 1 to 4 rating in accordance with Table 1 Figure 3 Visible ch
49、anges Calculate the rating to be reported as the mean value (to one decimal place) of all 18 ratings on three panels for each height used. If ratings from the same dropping height defer for more than one, all individual values should be reported beside the mean value.PD CEN/TS 16700:2014 CEN/TS 16700:2014 (E) 10 If ratings from the same dropping height defer for more than two, additional impacts should be made and extreme values to be ignored. If this does not resolve the situation the test
