《BS-5395-2-1984.pdf》由会员分享，可在线阅读，更多相关《BS-5395-2-1984.pdf（18页珍藏版）》请在三一文库上搜索。
1、BRITISH STANDARD BS 5395-2: 1984 Reprinted, incorporating Amendment No. 1 and Stairs, ladders and walkways Part 2: Code of practice for the design of helical and spiral stairs ICS 91.060.30 Corrigenda Nos. 1 and 2 Licensed CopyChinese University of Hong Kong, 11/04/2009 07:08, Uncontrolled Copy, (c)
2、 BSI BS 5395-2:1984 This British Standard, having been prepared under the direction of the Elements and components (of Diverse materials) for Buildings Standards Committee, was published under the authority of the Board of BSI and comes into effect on 31 January 1984 The following BSI references rel
3、ate to the work on this standard: Committee reference ECB/2 Draft for comment 82/12150 DC Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Elements and Components (of Diverse Materials) for Buildings Standards Committee (ECB/-) to Technic
4、al Committee ECB/2 upon which the following bodies were represented: Aluminium Federation British Woodworking Federation Concrete Society Department of Health and Social Security Department of the Environment, Building Research Establishment, Princes Risborough Laboratory Department of the Environme
5、nt, Housing and Construction Energy Industries Council Engineering Equipment and Materials Users Association Greater London Council Health and Safety Executive Incorporated Association of Architects and Surveyors Institution of Mechanical Engineers Institution of Structural Engineers Joinery Manager
6、s Association Ltd. London Transport Executive Royal Institute of British Architects Scottish Development Department Spiral Stair Manufacturers Association The following bodies were also represented in the drafting of the standard, through subcommittees and panels: Institution of Building Control Off
7、icers Co-opted members Amendments issued since publication Amd. No.Date of issueComments 6076July 1989Indicated by a sideline in the margin July 2008Corrigendum to replace poor quality figures BSI 2009 ISBN 978 0 580 67034 3 C2Table 2: “Minimum outer going“ corrected to “Maximum outer going“ This co
8、rrigendum corrects an error that appears in some versions of this standard only March 2009 . Licensed CopyChinese University of Hong Kong, 11/04/2009 07:08, Uncontrolled Copy, (c) BSI BS 5395-2:1984 i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2Definitions1 3Alternativ
9、e materials, components and methods of design and construction1 4Materials1 5Design6 6Fire protection and means of escape8 Appendix A Load tests9 Appendix B Design geometry10 Figure 1 Typical layouts for stairs2 Figure 2 Relationship between rise and going5 Figure 3 Measurement of clear width and go
10、ings7 Figure 4 Landings8 Figure 5 Maximum gap between column and tread8 Figure 6 Calculation of going9 Figure 7 Calculation of clear headroom11 Table 1 Structural materials3 Table 2 Sizes of stairs4 Publications referred to12 BSI 2009 Licensed CopyChinese University of Hong Kong, 11/04/2009 07:08, U
11、ncontrolled Copy, (c) BSI BS 5395-2:1984 ii Foreword This standard has been prepared under the direction of the Elements and Components (of Diverse Materials) for Building Standards Committee. As a consequence of the publication of this Part of this standard, the number of the existing BS 5395:1977
12、has been changed to BS 5395-1. BS 5395-3 covers industrial type stairs, ladders and walkways. This standard is based on accepted good practice by designers and manufacturers of helical and spiral stairs, It should be borne in mind that helical and spiral stairs are not normally permitted for use as
13、means of escape where large numbers of persons are involved. In drafting this standard the committee acknowledged the need for research into the structural behaviour of stairs. Appendix A describes a recommended procedure for load tests on stairs. Further investigations are required to determine the
14、 appropriate loads for each stair category. The proper functioning and durability of a prefabricated stair designed in accordance with this standard depends on care in handling during transportation and on site, as well as careful site storage, correct installation and temporary protection, and subs
15、equent proper maintenance. Some general advice is given in BS 5395-1, but the manufacturer should inform the purchaser in writing of the precautions necessary. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for th
16、eir 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 to 12, an inside back cover and a back cover. This standard has been updated (
17、see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. BSI 2009 Licensed CopyChinese University of Hong Kong, 11/04/2009 07:08, Uncontrolled Copy, (c) BSI BS 5395-2:1984 1 1 Scope This Part of this standard gives recomme
18、ndations for the design of helical and spiral stairs, to be used internally or externally in all types of building constructions. It covers only stairs which are circular on plan and does not deal with ramps. NOTE 1Appendix B gives guidance on the geometry of helical and spiral stairs. NOTE 2The tit
19、les of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this standard the following definitions apply. 2.1 spiral stair a stair describing a helix around a central column see Figure 1(a) 2.2 helical stair a stair describing a helix
20、around a central void see Figure 1(b) 2.3 going the chord length on plan between two points on consecutive tread nosings at the same radius from the geometric centre of the stair, measured as described in 5.4 2.4 rise the vertical distance between two consecutive steps 2.5 clear headroom the distanc
21、e measured vertically from the pitch line of a stair or from a floor or landing to any obstruction overhead 2.6 clear width the unobstructed walking area throughout the stairs rise, measured as described in 5.6 2.7 outside diameter the diameter of the outer edge of the handrail, strings or treads, w
22、hichever is the greater 2.8 pitch line a line drawn from the floor or landing below a stair to connect points on consecutive tread nosings at the same radius from the geometric centre of the stair 2.9 nosing the front edge of a tread 2.10 riser the part closing the front face of the step 2.11 tread
23、the horizontal part or upper surface of the step 3 Alternative materials, components and methods of design and construction Where materials, components and methods of design and construction are not covered by this standard or by any other British Standard, this is not necessarily to be regarded as
24、discouraging their use. The designer should satisfy himself by reference to appropriate manufacturers literature and test evidence issued by competent, independent authorities that the materials and methods to be employed are such as to ensure a level of performance at least equal to that obtained b
25、y following the recommendations of this standard. 4 Materials Structural materials should be selected from those listed in Table 1 and should be in accordance with the appropriate British Standard. Where stairs are constructed from two or more different materials, the materials should be compatible.
26、 For example, they should not give rise to electromagnetic or electrogalvanic action e.g. between different metals, chemical corrosion e.g. of metal fixings in timber, or differential movement e.g. between concrete and brickwork. For guidance on surface-finishing materials see clause 8 of BS 5395-1:
27、1977. BSI 2009 Licensed CopyChinese University of Hong Kong, 11/04/2009 07:08, Uncontrolled Copy, (c) BSI BS 5395-2:1984 2 (a) Spiral stair (b) Helical stair NOTE. Balusters are shown widely spaced for clarity. In areas frequented by children, the widest gap should not permit a sphere of 100 mm diam
28、eter to pass through. Figure 1 Typical layouts for stairs BSI 2009 Licensed CopyChinese University of Hong Kong, 11/04/2009 07:08, Uncontrolled Copy, (c) BSI BS 5395-2:1984 3 Table 1 Structural materials MaterialBritish StandardsOther recommendations Code of practiceSpecification ConcreteBS 8110 Rei
29、nforced and granolithic terrazzoBS 4357 Natural stoneBS 5390Not suitable for use in escape stairs (see clause 6) Cast stoneBS 5628-3BS 1217Not suitable for use in escape stairs (see clause 6) Hopton stone and York stone are particularly suitable as aggregates Brick and blockBS 5628-3BS 187 BS 3921 B
30、S 6073-1 AluminiumCP 118aNot suitable for use in escape stairs (see clause 6) Cast ironBS 1452 Copper alloysBS 2870Aluminium bronze (grades CA 101 to 106 inclusive) or phosphor bronze (grades PB 101 to 104 inclusive) should be used BS 2872 BS 2874 See fire safety recommendations in clause 6 Steel, i
31、ncluding stainless steel BS 449 BS 5950 BS 1449See fire safety recommendations in clause 6 Austenitic stainless steel grade SS 16 316 should be used for external stairs Plastics materialsBS 6180bNot suitable for use in escape stairs (see clause 6) Hardwoods Softwoods BS 5268-2BS 1186-1 and BS 1186-2
32、 Exterior grade plywoodBS 5268-2BS 6566-1 to BS 6566-8 Marine plywoodBS 5268-2BS 1088 b) where there is no inner handrail, measure the radial distance between the centre column or the outside1) edge of the inner string and the inside face of the outer handrail or the inside edge of the outer string,
33、 whichever is the nearer to the centre of the tread in each case see Figure 3(b). 5.7 Landings. Landings at storey levels should subtend an angle of not less than 60 at the geometric centre on plan see Figure 4(a). Intermediate or rest landings should have a plan area of not less than two consecutiv
34、e treads or subtend an angle of 45 at the geometric centre on plan, whichever is the greater see Figure 4(b). 5.8 Guarding of stairs and landings. Protection against falling should follow the recommendations of 12.3 of BS 5395-1:1977. For safety reasons any gap between the end of a tread and the cen
35、tre column of a stair should never exceed 100 mm (see Figure 5). Balustrades and handrails should follow the recommendations of BS 6180 provided that the definition of pitch line given in 2.8 of this standard is used. In areas frequented by children, the widest gap in a balustrade should not permit
36、a sphere of 100 mm diameter to pass through. An inner handrail should be provided for semi-public and public stairs (categories C, D and E in Table 2). 5.9 Passage of large objects. Designers should consider whether the minimum clearances recommended in Table 2 are sufficient for the passage of larg
37、e objects, such as furniture, coffins. The limiting factor in the size of the stairwell. However stairs may have balustrades and handrails that can be dismantled temporarily. ris the rise; gis the going. 1) In all cases, the term “outside” refers to the edge or face furthest from the centre of the s
38、tair. BSI 2009 Licensed CopyChinese University of Hong Kong, 11/04/2009 07:08, Uncontrolled Copy, (c) BSI BS 5395-2:1984 7 5.10 Deflection. Helical and spiral stairs should be designed to be rigid enough to give confidence to the user, since they can be subject to oscillations. Stairs should be desi
39、gned to limit deflections under working conditions to the maximum values given in the appropriate standard (see Table 1). 5.11 Accuracy. For general guidance on accuracy in building, see BS 5606. The maximum permissible deviation for any size should not exceed the appropriate value given in Table 2
40、of BS 5606:1978. For further guidance see 11.2.3 of BS 5395-1:1977. Consistency of rise and going are of prime importance for user confidence and safety. 5.12 Nosings. Nosings should be horizontal and straight between the pitch lines (see 2.8) corresponding to the inner and outer goings. (a) Spiral
41、stair with inner handrail(b) Spiral stair without inner handrail NOTE. Figure 3(a) shows a spiral stair only, but the same method of measurement applies to a helical stair. All dimensions are in millimetres. Figure 3 Measurement of clear width and goings 1 2 3 3 4 270 270 gi gc go 1 4 270 270 gi gc
42、go BSI 2009 Licensed CopyChinese University of Hong Kong, 11/04/2009 07:08, Uncontrolled Copy, (c) BSI BS 5395-2:1984 8 6 Fire protection and means of escape Stairs in most buildings form the main vertical escape routes and are often in the first protected areas reached by people escaping from a fir
43、e. The recommendations for planning, construction and protection of escape routes to prevent rapid spread of fire, given in CP 3: Chapter IV-12), or BS 5588-1,BS 5588-2, BS 5588-3 or BS 5588-8 as appropriate, should be followed. The minimum clear widths given in Table 2 may be insufficient for escap
44、e stairs, depending on the building use and the number of its occupants. The following materials should never be used to form the only escape stair in a building or a stair for fire fighting: a) materials having a low melting point, e.g. aluminium, owing to the likelihood of their early collapse whe
45、n exposed to heat; b) stone, since when subjected to heat or cold water during fire-fighting operations it can collapse without warning; c) plastics materials not covered by (a), since these give off toxic fumes when subjected to heat. NOTEFurther information may be obtained from Home Office, Scotti
46、sh Home and Health Department “Guide to the Fire Precaution Act 1971” Nos. 1, 2 and 3, available from HMSO. 2) To be revised as Part of BS 5588. (a) At storey level(b) Intermediate or rest landing Figure 4 Landings 60 45 Dimension is in millimetres. Figure 5 Maximum gap between column and tread 100
47、BSI 2009 Licensed CopyChinese University of Hong Kong, 11/04/2009 07:08, Uncontrolled Copy, (c) BSI BS 5395-2:1984 9 Appendix A Load tests The following procedure may be used to test helical and spiral stairs. a) Apply a uniformly distributed lead of 3 kN/m2 to 5 kN/m2 3) to each tread. Check deflec
48、tions and displacements. b) Remove the lead from all treads forming the lower 180 segment of the stair. Check deflections and displacements. c) Remove the load from all remaining treads except one tread at mid-height. Increase load on this tread to double the previous load. Check deflections and dis
49、placements. d) Check individual treads by placing on them two loads of 0.9 kN spaced 300 mm apart and placed symmetrically about the centre-line of the tread. 3) This range of uniformly distributed loads is taken from BS 6399-1. The actual value used should be chosen to suit the stair category and the intended function of the stair. Figure 6 Calculation of going Nb Rb g X Rs Rh Uo Rs2Uo 1 2 5 3 4 6 8 7 BSI 2009 Licensed CopyChinese University of Hong Kong, 11/04/2009 07:08, Uncontrolled Copy, (c) BSI B