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1、BRITISH STANDARD BS 4875-3: 1985 Strength and stability of furniture Part 3: Methods for determination of strength of settees UDC 684.433.3:645.412.3:620.1 Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 09:16:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4875-3:1985 This British Standard,
2、 having been prepared under the direction of the Furniture and Household Equipment Standards Committee, was published under the authority of the Board of BSI and comes into effect on 30 September 1985 BSI 03-1999 First published, as part of BS 4875-1, October 1972 First revision, as Part 3, Septembe
3、r 1985 The following BSI references relate to the work on this standard: Committee reference FHM/1 Draft for comment 82/36676 DC ISBN 0 580 14645 6 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Furniture and Household Equipment Standar
4、ds Committee (FHM/-) to Technical Committee FHM/1 upon which the following bodies were represented: British Rubber Manufacturers Association Business Equipment Trade Association Consumer Standards Advisory Committee of BSI Consumers Association Department of Education and Science Design Council Furn
5、iture Industry Research Association Greater London Council Local Authorities Management Services and Computer Committee Mail Order Traders Association of Great Britain National Bedding Federation Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun
6、, na, Fri Dec 01 09:16:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4875-3:1985 BSI 03-1999i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2Principle1 3General requirements for tests1 4Inspection before and after testing3 5Apparatus3 6Determination of seat and back lo
7、ading points8 7Procedures8 8Interpretation of results15 9Test report15 Appendix A Explanation of furniture test levels16 Figure 1 Loading point template4 Figure 2 Position of loading point template5 Figure 3 Loading surface curves for chair seat and back loading template5 Figure 4 Seat loading pad (
8、plan and side elevations)6 Figure 5 Smaller seat loading pad6 Figure 6 Back loading pad6 Figure 7 Impactor7 Figure 8 Impact hammer9 Figure 9 Seat static load test10 Figure 10 Back static load test10 Figure 11 Arm and wing sideways static load tests11 Figure 12 Arm downwards static load tests11 Figur
9、e 13 Seat fatigue test12 Figure 14 Back fatigue test13 Figure 15 Diagonal base test14 Figure 16 Arm impact test14 Figure 17 Drop test15 Table 1 Test data (purpose of each test)2 Table 2 Summary of test procedures2 Table 3 Relationship of test levels to use of furniture16 Table 4 Specific application
10、s for furniture in relation to test levels16 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 09:16:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4875-3:1985 ii BSI 03-1999 Foreword This Part of BS 4875 has been prepared under the direction of the F
11、urniture and Household Equipment Standards Committee, and forms a revision of part of BS 4875-1:1972. Together with Parts 1, 2 and 4 it supersedes BS 4875-1:1972 which is withdrawn. The major changes introduced by this revision are that the realism of the tests has been improved by specifying the us
12、e of more realistic apparatus, and a template is specified to determine the loading points. The opportunity has been taken to align the standard with an international standard in course of preparation in ISO/TC 136/SC 1 “Furniture Test methods”. The tests described in this Part of BS 4875 reproduce
13、normal use and common types of mis-use to which seating may be subjected. As a result the methods are applicable to nearly all seating. Four test levels are given for the tests to cover the variations in severity of end-use that arises from the use of delicate styles, short life furniture, robust se
14、rviceable styles, etc. Whilst the tests reproduce normal use and common types of mis-use they do not reproduce any abuse to which the article may be subjected. Appendix A gives an explanation of the furniture test levels used in this standard. The tests are designed to be applied to an article that
15、is fully assembled and ready for use and are only intended to determine strength of the structure; they do not assess durability of filling materials, upholstery fabrics or foam cushions. The tests also do not reproduce the effects caused by degradation of structural materials by sunlight or chemica
16、l attack. Other Parts of BS 4875 are as follows: Part 1: Methods for determination of strength of chairs and stools; Part 2: Methods for determination of stability of chairs and stools; Part 4: Methods for determination of stability of settees; Part 5: Methods for determination of strength of tables
17、 and trolleys; Part 6: Methods for determination of stability of tables and trolleys; Part 7: Methods for determination of strength of storage furniture; Part 8: Methods for determination of stability of storage furniture. Attention is drawn to BS 6250 which specifies performance requirements for do
18、mestic and contract furniture using this standard as the method of test, and to BS 5459 and BS 5873 which specify performance requirements for office and educational furniture using methods that are very similar to those in this standard. A British Standard does not purport to include all the necess
19、ary 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 cover, an inside front cover, pages i and ii, pages 1
20、 to 16, 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. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 09:16:03 GMT+00:00 2006, Uncont
21、rolled Copy, (c) BSI BS 4875-3:1985 BSI 03-19991 1 Scope This Part of BS 4875 describes methods for determination of strength of the structure of all types of settees, and other articles such as benches with seats for from two to four persons. This standard does not apply to chairs or stools which a
22、re covered by BS 4875-1. It does not apply to multiple seating units for stadium seating as the loads applied are not representative of this type of use. NOTE 1Tests carried out according to the requirements of this standard are intended to demonstrate the ability of the item to give satisfactory se
23、rvice in its intended environment. It should be understood that such tests do not ensure that structural failure will not eventually occur as a result of habitual mis-use or after an excessively long period of service. NOTE 2The titles of the publications referred to in this standard are listed on t
24、he inside back cover. 2 Principle 2.1 General The principle is to determine the strength of the structure of an article of furniture by applying to various parts loads or forces simulating normal functional use, as well as acceptable mis-use, according to a graded scale of severity (see Appendix A).
25、 The interrelation of the tests is shown in Table 1 and a summary is given in Table 2. The sequence as a whole determines the following: a) static strength and initial damage; b) fatigue strength and damage propagation; c) ability to withstand acceptable mis-use and demonstration of sufficient resid
26、ual strength. The severity of loading is graded by varying the number of applications or the magnitude of forces applied. 2.2 Static tests The principle of static tests is to assess the static strength of the article under the high levels of loading that only occasionally occur. 2.3 Fatigue tests Th
27、e principle of fatigue tests is to assess the strength of the component parts of the article under the repeated operations, movement, or applications of loads occurring during daily use. 2.4 Impact tests The principle of impact tests is to assess the impact strength of the article under the rapid ra
28、tes of loading that only occasionally occur. 3 General requirements for tests 3.1 Test loading All loads and forces shall be measured to an accuracy of 5 %. NOTEThe tests may in certain cases be carried out by means of loads or forces. For practical purposes, a force of 10 N may be taken to be equal
29、 to the downward force due to a mass of 1 kg. The apparatus used to apply seat loading shall not restrain the article from overturning, nor hinder horizontal movement of the article when the back force is applied. 3.2 Moisture content and conditioning Before the tests are commenced the article shall
30、 be sufficiently old to ensure that all component materials have developed their full strength. At least 4 weeks in normal conditions shall elapse from manufacture in the case of glued joints in timber, plastics moulded parts, etc. Parts made of timber products shall be checked with an electric mois
31、ture meter to ensure that the moisture content is between 8 % and 12 %. If the moisture content is too high the article shall be allowed to dry out in a warm ventilated room until the moisture content is between 8 % and 12 %. If a standard atmosphere is required for conditioning or testing, that atm
32、osphere shall be at a temperature of 23 3 C and a relative humidity of 505 %. 3.3 Emergency tests When there is not time for furniture to be aged or to reach equilibrium the moisture content shall be measured where applicable at the beginning and at the end of the testing sequence, and these measure
33、ments shall be included in the report if they are outside the limits specified, together with the age of the article when testing commenced. 3.4 Rate of carrying out the tests The forces shall be applied at a sufficiently slow rate to ensure that negligible dynamic load is applied and also to ensure
34、 that kinetic heating does not occur. During the static load tests described in 7.1 to 7.3 the forces shall be maintained for at least 10 s during each cycle. NOTEIt is recommended that the tests are carried out at a maximum rate of six cycles per minute. 3.5 Setting-up of furniture The articles sha
35、ll be tested as delivered. Self-assembly furniture shall be assembled according to instructions supplied with the article. If the article can be combined in different ways the most adverse combination shall be used for each test. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 09:16:03 GMT+00
36、:00 2006, Uncontrolled Copy, (c) BSI BS 4875-3:1985 2 BSI 03-1999 Table 1 Test data (purpose of each test) Table 2 Summary of test procedures Sequence NumberTitlePrimary purpose Secondary purposeType 11aSeat static load test Basic strength Damage initiation Functional 1bBack static load test 22Arm a
37、nd wing sideways static load test 33Arm downwards static load test 44a 4b Seat fatigue test Back fatigue test Service durability Damage propagation 5aLeg forwards and sideways test Handling strength Residual strength Acceptable misuse 55bStatic load test 5cDiagonal base test 66Seat impact test Impac
38、t strength 77aBack impact test 7bArm impact test 88Drop test NumberTitleDescriptionTest levela (see Appendix A) 2345 1aSeat static load testSeat force (in N)1 1001 3001 6002 000 1bBack static load testBack force (in N) at each pad 410560760760 Balancing seat force (in N) at each pad 1 1001 3001 6002
39、 000 2Arm sideways static load testForce applied (in N)300400600900 Wing sideways static load testForce applied (in N)200300400500 3Arm downwards static load test Force applied (in N)7008009001 000 4aSeat fatigue testNumber of cycles 950 N seat force 25 000 50 000 100 000 200 000 4bBack fatigue test
40、Number of cycles 400 N back force 25 000 50 000 100 000 200 000 5aLeg forwards static load testMaximum forward force (in N) 375500620760 5bLeg sideways static load testMaximum forward force (in N) 300390490760 Balancing seat force (in N)7801 0001 2501 800 5cDiagonal base force testForce applied (in
41、N)250375500620 6Seat impact testDrop height (in mm)140180240300 7aBack impact test andDrop height (in mm)120210330620 7bArm impact testAngle (in degrees)28384868 8Drop testDrop height (in mm)75100150200 a Test level 1 does not apply to this standard; the remaining test levels are numbered 2 to 5 to
42、correspond with the tests described in BS 4875-1. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 09:16:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4875-3:1985 BSI 03-19993 4 Inspection before and after testing Immediately before commencement of testing, each article shall be thoroughly
43、inspected. Any defects in the members, joints or attachments shall be noted so that they are not attributed to the effect of the tests when the tests have been completed. A complete dimensional check shall be carried out on all articles that may suffer permanent deformation as a result of testing. I
44、mmediately after completion of the tests, the article shall again be thoroughly inspected. Any apparent defects shall be noted and a determination made of any changes that have taken place since the initial inspection. Fittings in self-assembly furniture shall be tightened before testing, and after
45、each test level if testing is carried out at more than one test level. NOTEFittings in self-assembly furniture that come loose during the tests do not constitute a test failure. Manufacturers of self-assembly furniture should be recommended to issue instructions with the furniture that fittings shou
46、ld be tightened occasionally. Each article shall be subjected to each of the tests at the same test level in the order specified and the occurrence of any of the following shall be recorded as defects affecting the strength of the article: a) any fracture of any member, joint or component, including
47、 seat suspensions and castors; b) any fracture or cracking through the thickness of any part of a structural shell; c) any loosening, shown to be permanent by hand pressure applied to suitable members, of joints intended to be rigid; d) any loosening of the underframe or base inserts moulded into a
48、structural shell relative to the shell surface, shown to be permanent by means of hand pressure applied to the underframe or base; e) any free movement in the back, arms, legs or other components of the article greater than that noted in the initial inspection; f) any deformation of any part of the
49、article or any cracks that will adversely affect its appearance or strength; g) any impairment of the operation of any mechanical part; h) any clearly audible noise developed during testing. NOTEThe test results are only valid for the article tested. When the test results are intended to be applied to other similar articles, the test specimen should be representative of the production model. Information on the scale of sampling to be employed can be obtained from BS 6001. 5 Apparatus NOTEFor details of the sou