1、BRITISH STANDARD BS3962-6: 1980 Incorporating Amendment No.1 Methods of test for Finishes for wooden furniture Part 6: Assessment of resistance to mechanical damage UDC 684.4.041.059.1:667.638.6:620.178.1BS3962-6:1980 This British Standard, having been prepared under the directionof the Pigments, Pa
2、intsand Varnishes StandardsCommittee, was published under the authority ofthe Executive Board and comesinto effect on 30 May1980 BSI 03-1999 First published February 1975 First revision May 1980 The following BSI references relate to the work on this standard: Committee reference PVC/5 Draft for com
3、ment 77/53137 DC ISBN 0 580 11342 6 Cooperating organizations The Pigments, Paints and Varnishes Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: British C
4、olour Makers Association Builders Merchants Federation Consumers Association* Department of the Environment (Building Research Establishment) Department of the Environment (PSA)* Department of Industry (Chemicals and Textiles) Department of Industry (Laboratory of the Government Chemist) Greater Lon
5、don Council London Transport Executive Ministry of Defence Oil and Colour Chemists Association Paint Research Association Paintmakers Association of Great Britain Ltd* Post Office Royal Institute of British Architects Society of Chemical Industry Titanium Pigment Manufacturers Technical Committee Wh
6、ite Lead Manufacturers Association Zinc Development Association Zinc Pigment Development Association The organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: Associati
7、on of County Councils British Woodworking Federation Department of Education and Science Department of the Environment (Joint Fire Research Organisation of the Department of the Environment and Fire Offices Committee) Furniture Industry Research Association Amendments issued since publication Amd. N
8、o. Date of issue Comments 5937 April 1989 Indicated by a sideline in the marginBS 3962-6:1980 BSI 03-1999 i Contents Page Cooperating organizations Inside front cover Foreword ii 1 Scope 1 2 References 1 3 Principle 1 4 Preparation of test surface 1 5 Test procedure 1 6 Assessment and reporting of r
9、esults 4 Figure 1 Impact test. Method of viewing test area 5 Figure 2 Impact test. Diagram showing rating scale 6 Figure 3 Typical illustrations of cross-cut rating 7 Figure 4 Cross-cut test. Details of cutting blade 8 Figure 5 Cross-cut test. Details of suitable template 9 Figure 6 Cross-cut test.
10、Details of suitable blade holder 10 Figure 7 Scrape test. Typical layout of scrape test machine 11 Figure 8 Scrape test. Details of scraper blade 12 Figure 9 Scrape test. Details of scraper blade holder 12 Figure 10 Scrape test. Details of blade clamp body 13 Publications referred to Inside back cov
11、erBS3962-6:1980 ii BSI 03-1999 Foreword This Part of this British Standard has been prepared under the direction of the Pigments, Paints and Varnishes Standards Committee as one of a series of standard methods for testing and assessing the performance of finishes for wooden furniture. BS3962-6 was f
12、irst published in1975 in the series of standard methods for testing the performance of clear finishes for wooden furniture. An increase in the use of pigmented finishes for furniture has now made it desirable to broaden the scope of the test method to include such finishes. In addition the opportuni
13、ty has been taken to amend the rating codes to align with international practice. The method is designed to test the extent to which finishes for wooden furniture withstand damage from mechanical knocks or scrapes. It provides a method for comparing different finishes but can also be used to determi
14、ne whether or not a sample complies with the requirements detailed in a product specification or other document. In view of the diversity of woods and finishing systems used in the furniture industry, it is impracticable to specify a uniform standard test substrate and method of preparation of the f
15、inishing system. These should be the subject of agreement between the purchaser and the supplier. This method seeks only to stipulate a standard procedure for testing a wooden panel coated with the appropriate finishing system. Correlation trials between laboratory testing of finishes and subjective
16、 assessment of their resistance to mechanical damage in use have shown that no single test is sufficient to define the mechanical properties of a finish. These trials, however, showed that good correlation with performance in use could be obtained by the use of three tests, each with a rating system
17、 for assessing the results. Although the rating systems used have been made as objective as possible, they still contain a large subjective component. Consequently, to cater for the inherent variability present when subjective decisions have to be made, it is recommended that not fewer than five obs
18、ervers should examine and assess the tested surfaces. Subject to agreement between the purchaser and the supplier, fewer observers may be used provided that the observers are experienced in these types of assessment. The rating in each test is the median value of the assessment of the observers, the
19、 assessments being determined by a procedure described in detail in clause6. No attempt has been made to assess the ease with which the finish may be restored. This Part of this British Standard describes a method of test only (comprising three independent tests), to which reference may be made in a
20、 specification in which test conditions and acceptable performance levels have been specified. A statement that a wood finishing system complies with the requirements of BS3962 should not be used, as it is meaningless. Other Parts of this standard are: Part 1: Assessment of low angle glare by measur
21、ement of specular gloss at85; Part 2: Assessment of surface resistance to wet heat; Part 3: Assessment of surface resistance to dry heat; Part 4: Assessment of surface resistance to cold liquids; Part 5: Assessment of surface resistance to cold oils and fats.BS 3962-6:1980 BSI 03-1999 iii A British
22、Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front co
23、ver, an inside front cover, pagesi toiv, pages1to14, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv blankBS3962-6:1980 BSI 03-1999 1 1 Scop
24、e 1.1 This Part of this British Standard describes three independent tests which together provide a means of assessing the resistance of a wood finishing system to damage as a result of mechanical action. NOTEFor the purposes of this British Standard, the terms “wood” and “wooden” include the range
25、of materials manufactured from wood, e.g.blockboard, particle board, etc., used in the furniture industry. 1.2 The three tests used together provide a means of comparing a number of finishing systems or as a control check test to ensure that a consistent quality of supplies is being achieved or main
26、tained. 2 References The titles of the publications referred to in this standard are listed on the inside back cover. 3 Principle 3.1 Impact test. A steel ball is dropped from a specified height on to a test panel. The damage to the finish, in and around the indentation, is assessed by a number of o
27、bservers by reference to a descriptive numerical rating code. 3.2 Cross-cut test. A lattice pattern consisting of two sets of cuts at right angles, each set consisting of eleven parallel cuts2mm apart, is made on the test panel using a standard sharp implement. Loose pieces of finish are removed wit
28、h a soft brush. The test area is assessed by a number of observers by reference to a descriptive and illustrative numerical rating code. NOTEThe cross-cut test as specified in this standard is similar to that standardized for paint testing in ISO2409-1972 and BS3900-E6. For testing wood finishes, ho
29、wever, it has been found necessary to describe the apparatus and procedure more precisely and to provide photographs in place of diagrams to represent standard ratings. 3.3 Scrape test. A standard scraper blade is drawn over a test surface, across the grain where appropriate, at a constant speed und
30、er a gradually increasing force. The force acting upon the scraper blade at the point at which it first penetrates the surface is measured, and a numerical rating is given according to this force. In addition, the force acting upon the scraper blade at the point at which it first penetrates the subs
31、trate is also measured, and a numerical rating is given according to this force. The results of the test are assessed by a number of observers. 3.4 Method of assessment. The median value of the individual assessments in a test determines the rating to be given to the finishing system for each specif
32、ied test. The ratings for each of the three tests considered together provide a means of assessing the resistance to mechanical damage of the wood finishing system. 4 Preparation of test surface 4.1 Test panel. The test panel shall be of an agreed wooden substrate and substantially flat. It shall be
33、 not less than400mm 100mm 10mm. If the panel surface has a grain pattern, the400mm dimension shall be across the grain. 4.2 Finishing of test panel. Apply the full finishing system by the appropriate method of application to the agreed wooden substrate, suitably prepared and conforming to the dimens
34、ions specified in4.1. The application rates of the individual coats of material, the drying period and conditions and the surface preparation between coats, e.g.sanding, shall be agreed between the purchaser and the supplier. 4.3 Ageing of test panel. Allow the final coat to age at a room temperatur
35、e not lower than15C with free access of air for an agreed period before test. The period shall be not less than28 days except for special purposes, in which case the period shall be agreed between the purchaser and the supplier. 5 Test procedure 5.1 General. Carry out three separate tests, namely th
36、e impact test, cross-cut test and scrape test. Carry out each of the three tests at not less than two positions. Ensure that the test positions for a particular test are as random as possible, and that they do not lie on the same grain structure, if this is visible. Carry out the tests at a room tem
37、perature of23 2 C. 5.2 Impact test 5.2.1 Apparatus 5.2.1.1 Steel ball. A steel ball bearing, diameter19.1mm (nominal0.75in). 5.2.1.2 Viewing light, consisting of a source of direct light. A60W frosted lamp in an adjustable desk luminaire 1)is suitable. 5.2.1.3 Viewing lens. A hand lens with a magnif
38、ication of 2 to 3. 1) This is the preferred term for an electric lamp fitting.BS3962-6:1980 2 BSI 03-1999 5.2.2 Procedure 5.2.2.1 With the test panel held in a stable horizontal position on a firm base, drop the steel ball(5.2.1.1) on to it from a height of2.00 0.01m, taking suitable measures to pre
39、vent multiple impacts of the ball. 5.2.2.2 With the test panel in a vertical position, carefully examine the test area using the following procedure. Place the viewing light(5.2.1.2) at a convenient height shining downward. If the panel surface has a grain pattern, hold the panel with the grain upri
40、ght, directly under the light and as close to it as is convenient. Keeping the test area directly under the light, rock the panel so that the angle between the direction of the light and the plane of the panel varies between0 and30 (see Figure 1). During this rocking movement, examine the test area
41、using the viewing lens(5.2.1.3). Turn the test face of the panel through90 and repeat the procedure. Assess the general appearance of the panel as described in5.2.3. 5.2.3 Method of rating. Rate the test area according to the following code (see Figure 2). NOTE 1In assessing the damage incurred by t
42、he finish, mechanical deformation of the substrate should not be considered as damage. NOTE 2The cracks need not be complete circles but may have discontinuities, appearing as short arcs. Using this criterion, the number of cracks stated in the definition should be applied literally. NOTE 3Some disc
43、retion is necessary when deciding whether cracks are outside the area of the indentation, as this area is not always well defined. In general, these cracks fall within a well-defined radius. NOTE 4The rating codes now align with international practice. This has the effect of increasing each numerica
44、l rating by1 unit from that given in the previous edition of this standard (e.g.a rating of3 in this edition corresponds to a rating of2previously). 5.3 Cross-cut test 5.3.1 Introduction. This method is similar to that described in BS3900-E6, except that, in this method, the cutting tool is more clo
45、sely defined and photographs are given for illustrating the ratings (see Figure 3). NOTEFor the cross-cut test, the depth of cut(0.3mm) has been chosen so as to penetrate most finishes without excessive penetration of the substrate. This is not so in a few cases, e.g.some thick polyester finishes, b
46、ut for these the excessive force required to cut through the film makes the test impracticable. The surface of the substrate can, in certain circumstances, have a marked influence on the results of this test, e.g.a poor surface may break down where the cutting blade penetrates it. In such cases, gre
47、at care is necessary in the interpretation of the test results. 5.3.2 Apparatus 5.3.2.1 Cutting blade. A trimming knife blade manufactured from carbon steel,0.43 0.03mm thick, hardened and tempered to give a hardness in the range HV750 to HV820 when tested in accordance with the procedure given in B
48、S427-1. The cutting edge shall be an inclusive angle of20 to25, equally disposed about the centre line of the blade ground or ground and stropped to form a closed edge. The ends of the blade shall be at an angle to the cutting edge of approximately55 to form a sharp point (see Figure 4). 2) 5.3.2.2
49、Template. A metal template to produce a grid consisting of eleven cuts2 0.01mm apart. A suitable design, illustrated in Figure 5, consists of two parts: part2 fits into part1 in two different positions so that groups of cuts can be made at right angles to each other. 5.3.2.3 Blade holder. A metal blade holder to hold the cutting blade(5.3.2.1) in such a way that, when used with the template(5.3.2.2), the depth of cut is constant. A suitable design is given in Figure 6. 5.3.2.4 A soft brush. 5.3.2.5 Viewing light, consisting of
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