《BS-7553-1992.pdf》由会员分享，可在线阅读，更多相关《BS-7553-1992.pdf（16页珍藏版）》请在三一文库上搜索。
1、BRITISH STANDARD BS 7553:1992 Incorporating Amendment No. 1 Specification for Loft ladders Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 15:02:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7553:1992 This British Standard, having been prepared under the dire
2、ction of the Technical Sector Board for Building and Civil Engineering, was published under the authority of the Standards Board and comes into effect on 31 January 1992 BSI 03-1999 The following BSI references relate to the work on this standard: Committee reference B/512 Draft for comment 90/16695
3、 DC Draft for comment 91/16296 DC ISBN 0 580 20493 6 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Technical Sector Board for Building and Civil Engineering (B/-) to Technical Committee B/512, upon which the following bodies were repre
4、sented: Aluminium Federation Association for Consumer Research (ACRE) British Hardware and Housewares Manufacturers Association British Ladder Manufacturers Association British Plastics Federation British Telecommunications plc Consumer Policy Committee of BSI Department of the Environment (Building
5、 Research Establishment) Department of Trade and Industry (Consumer Safety Unit, CA Division) Electricity Industry in United Kingdom Health and Safety Executive Institute of Trading Standards Administration National Federation of Master Steeplejacks and Lighting Conductor Engineers Refractory Contra
6、ctors Association Amendments issued since publication Amd. No.DateComments 7417December 1992 Indicated by a sideline in the margin Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 15:02:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7553:1992 BSI 03-1999i Conte
7、nts Page Committees responsible Inside front cover Forewordii 1Scope1 2Definitions1 3Classification of duty rating1 4Marking1 5Instructions2 6Construction2 7Installation2 8Performance2 Appendix A General information on tests4 Appendix B Test for deflection under load4 Appendix C Horn deflection test
8、4 Appendix D Test for strength of rungs and treads4 Appendix E Ladder stops test6 Appendix F Load, fatigue and impact tests on the complete ladder6 Appendix G Torsion test for rungs and treads7 Appendix H Handrail test9 Appendix J Use of plastics materials in loft ladders9 Figure 1 Arrangement for h
9、orn deflection test5 Figure 2 Ladder stops test6 Figure 3 Typical arrangement for load and fatigue tests8 Figure 4 Arrangement for impact test9 Figure 5 Handrail test10 Table 1 Loads for deflection test4 Table 2 Test loads for horn deflection test4 Table 3 Test loads for rungs and treads4 Table 4 Lo
10、ad and fatigue tests7 Table 5 Loads for impact test7 Table 6 Test loads for handrail test9 Publication(s) referred toInside back cover Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 15:02:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7553:1992 ii BSI 03-1999
11、 Foreword This British Standard has been prepared under the direction of the Technical Sector Board for Building and Civil Engineering following a request by the Department of Trade and Industry, Consumer Safety Unit. There is at present no work on this subject in Technical Committee TC 93 “Ladders”
12、 of the European Committee for Standardization (CEN). Portable timber ladders are covered by BS 1129, portable aluminium ladders by BS 2037 and step stools by BS 7377. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsibl
13、e for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Nevertheless, this British Standard has been submitted for approval under the Approval of Safety Standards Regulations 1987 as a means of compliance with the general safety
14、requirement imposed by Section 10 of the Consumer Protection Act 1987. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 10, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments
15、incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 15:02:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7553:1992 BSI 03-19991 1 Scope This British Standard specifies requireme
16、nts for construction and performance for loft ladders. NOTE 1General information on the test procedures required by this standard is given in Appendix A. Advice on use of plastics materials is given in Appendix J. NOTE 2The titles of the publications referred to in this standard are listed on the in
17、side back over. 2 Definitions For the purposes of this British Standard the following definitions apply. 2.1 loft ladder a ladder designed to be permanently fixed at its top end with sliding or hinged sections permitting it to be lowered to and raised from a lower level to provide access to a loft o
18、r similar point at a higher level 2.2 duty rating maximum combined weight of user and load 2.3 rung horizontal climbing support with a circular cross section, or with a basically circular cross section with a flat top 2.4 tread horizontal climbing support with a rectangular cross section 2.5 stiles
19、the side members to which the rungs, treads or cross-bearers are fitted 2.6 horns portions of the stile at each end beyond the lowest and the highest rung or tread 3 Classification of duty rating The ladders covered by this standard shall be classified according to the general domestic conditions an
20、d probable frequency of use for which they are suitable, as follows: a) Heavy use (class H). For relatively high frequency and onerous conditions of use and storage. Duty rating 150 kg (23.6 stones). b) General use (class G). For relatively low frequency and non-onerous conditions of use and storage
21、. Duty rating 100 kg (15.7 stones). 4 Marking 4.1 Ladders shall be clearly and durably marked with the information specified in 4.2 and 4.3. Compliance shall be checked by inspection and by rubbing the marking lightly, first for 15 s with a cloth soaked in water and then for 15 s with a cloth soaked
22、 in petroleum spirit. There shall be no reduction in legibility at the conclusion of the test. Adhesive labels, where used, shall not have worked loose or become curled at the edges. Tie on labels shall not be used to provide the information specified in 4.2 and 4.3. 4.2 All ladders shall be marked
23、with the following: a) the name, trade mark or other means of identification of the manufacturer or supplier; b) the number and date of this British Standard, i.e. BS 7553:19921); c) the class and duty rating, e.g. “Class H Heavy use; rating 150 kg (23.6 stones) max”. 4.3 Loft ladders shall be provi
24、ded with a label displaying at least the following wording on a background coloured blue for class H, and red for class G. “Use in accordance with manufacturers instructions. Ensure installation is in accordance with the manufacturers instructions. Never use damaged equipment. Ensure both feet of la
25、dder are firm and level. Ensure all locks are engaged. Keep a secure grip. Check clearance at top and access Avoid electrical hazards.” 1) Marking BS 7553:1992 on or in relation to a product represents a manufacturers declaration of conformity, i.e. a claim by or on behalf of the manufacturer that t
26、he product meets the requirements of the standard. The accuracy of the claim is therefore solely the responsibility of the person making the claim. Such a declaration is not to be confused with third party certification of conformity, which may also be desirable. Licensed Copy: London South Bank Uni
27、versity, London South Bank University, Fri Dec 08 15:02:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7553:1992 2 BSI 03-1999 5 Instructions Clear instructions for safe installation and use shall be supplied with each ladder. In particular, installation instructions shall not assume any specialis
28、t knowledge on the part of the installer. The following information shall be clearly visible before purchase, for example in a clear plastics pack attached to the ladder: a) the range of dimensions between the floor and the nominal loft level for which the ladder is suitable; b) the size of opening
29、required; c) the clearance required for storage. 6 Construction 6.1 Sharp edges In order to avoid injuries during normal use, including stowing and unstowing, the following items shall be complied with in the design of the loft ladder. a) Accessible edges, corners and protruding parts shall be free
30、of burrs. b) Edges shall be chamfered or rounded. c) Folding mechanisms and folding frames shall avoid fingertraps. This should be achieved by avoiding face to face contact of hinged parts which shall have a clearance sufficient to admit a 15 mm diameter rod. 6.2 Fixings Fixings of ladders shall be
31、designed to ensure that the ladder, when correctly fitted, is securely attached to its permanent point of support (see 6.6). 6.3 Stiles The minimum clear width between the stiles shall be 240 mm. 6.4 Treads and rungs 6.4.1 Treads or rungs shall be uniformly spaced when the ladder is in the climbing
32、position. 6.4.2 Treads or rungs other than when manufactured from timber shall have a textured surface to reduce slipping. NOTEThis surface may be integral or formed by applied material. In the design climbing position the surface of treads or flat top rungs shall be horizontal to within 3. 6.4.3 Tr
33、ead or rung spacing (pitch) shall be a minimum of 225 mm and a maximum of 300 mm measured along the stiles. The distance from the floor to the upper surface of the lowest tread or rung shall be 125 mm to 300 mm. The spacing of rungs or treads on an individual ladder shall not vary by more than 2.0 m
34、m from the nominal spacing. 6.4.4 When the ladder is correctly installed and extended to its working height, the distance from the loft landing to the tread below shall not be greater than the tread pitch measured along the stile. 6.5 Prevention of longitudinal movement A multi-section ladder shall
35、be fitted with a means of preventing longitudinal movement between adjacent sections during use, for example catches. 6.6 Descent control A means of controlling the descent of the ladder shall be provided to the position where it can be controlled by the users hand. 6.7 Safety stops Fixed stops shal
36、l be provided to prevent the top of the ladder from falling out of its permanent fixing point. Complete section disengagement during the unstowing operation shall be prevented. Spring loaded or other types of disengagement stops shall not be used alone to prevent complete section disengagement. 6.8
37、Climbing angle Ladders shall be so designed that when correctly fitted and adjusted the climbing angle is not more than 80 and not less than 65 from horizontal. 6.9 Feet The lowest point of the ladder shall be designed to prevent damage to floor coverings. 7 Installation Installation of the ladder s
38、hall not require the use of specialist knowledge or equipment by the customer (see clause 5). 8 Performance 8.1 Deflection under load When tested in accordance with Appendix B the deflection of the loaded stile shall not exceed the limit determined from the expression: Deflection (maximum) = 0.027S
39、where S is effective span (in mm) In addition, after removal of the test load there shall be no permanent damage and the residual deflection shall not exceed 1 mm per metre of effective span. 8.2 Horn deflection When tested in accordance with Appendix C, the residual deflection of either stile shall
40、 not exceed 6 mm. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 15:02:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7553:1992 BSI 03-19993 8.3 Strength of rungs and treads When tested in accordance with Appendix D the rungs or treads shall support the load.
41、 In addition, after removal of the test load there shall be no permanent damage and the residual deflection shall not exceed 1 mm. 8.4 Stops Ladders in which the top section moves against the loft fixing point by sliding or telescopic action shall be tested in accordance with Appendix E. NOTEThe tes
42、t described in Appendix E is not applicable to ladders which have devices to permanently override the ladder stops. When tested in accordance with Appendix E the stops shall remain in position and sections shall not become disengaged. 8.5 Load, fatigue and impact tests When tested in accordance with
43、 Appendix F, on completion of all the tests described in F.1 to F.4 there shall be no structural damage, the ladder shall be capable of being stowed and unstowed and the residual deflection of the stiles and treads shall not exceed 20 mm per metre of length. 8.6 Rung or tread rotation When tested in
44、 accordance with Appendix G relative movement in the connection between the stile and the rung or tread shall not exceed 2.5. The permanent deformation of the rung or tread shall not exceed 1. 8.7 Handrails When a handrail is fitted, tests in accordance with Appendix H shall be performed. Upon compl
45、etion of the tests in Appendix H there shall be no failure of handrail fixings. The permanent deformation at the points of application of load shall not exceed 15 mm. The distance between the stile and the handrail during the test shall not be less than 15 mm. NOTEFolding mechanisms and frames shoul
46、d avoid finger traps. Whenever possible this should be achieved by having a clearance sufficient to admit a 15 mm diameter rod. 8.8 Order of tests and tolerances on loading The tests shall be done in the order in which they are described in the standard. Tolerances on loading shall be in accordance
47、with BS 4875. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 15:02:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7553:1992 4 BSI 03-1999 Appendix A General information on tests The tests described in Appendix B to Appendix H are intended to be used during pr
48、oduct development, or where there is a change in the design or material specification that affects the performance of a ladder, or if a definitive means of checking compliance is required. Tests need be applied to only one of a range of products where the feature being tested is common or identical
49、to the rest of the range. Similarly, if the longest stile of a common section passes the tests then it will be unnecessary to test shorter products for this property. Throughout the tests, visible marking of the material caused by the application of the test loads or by the supports is not regarded as damage provided the shape of the section is not distorted. Appendix B Test for deflection under load If this test is being applied to an extendable ladder, extend it fully before the test is commenced. With the climbing face uppermost, support