1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 7903 : 1997 ICS 93.080
2、.30 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Guide to Selection and use of gully tops and manhole covers for installation within the highwayBS 7903 : 1997 This British Standard, having been prepared under the direction of the Sector Board for Building and Civil Engineer
3、ing, was published under the authority of the Standards Board and comes into effect on 15 November 1997 BSI 1997 The following BSI references relate to the work on this standard: Committee reference B/505/4 Draft for comment 96/107298 DC ISBN 0 580 27696 1 Amendments issued since publication Amd. No
4、. Date Text affected Committees responsible for this British Standard The preparation of this British Standard was entrusted by Technical Committee B/505, Wastewater Engineering, to Subcommittee B/505/4, Manhole covers and other road fittings, upon which the following bodies were represented: Britis
5、h Foundry Association British Plastics Federation British Precast Concrete Federation Chartered Institute of Water and Environmental Management Clay Pipe Development Association Concrete Pipe Association County Surveyors Society Ductile Iron Pipe Committee Fabricated Access Covers Association Galvan
6、isers Association Highways Agency Institute of British Foundrymen Institute of Building Control Institute of Civil Engineers (Works and Highways Committee) London Technical Advisors Group METCOM Society of British Water Industries Water Companies Association Water Services Association of England and
7、 WalesBS 7903 : 1997 BSI 1997 i Contents Page Committees responsible Inside front cover Foreword ii Guide 1 Scope 1 2 References 1 3 Definitions 1 4 Classification 1 5 Place of installation 1 6 Materials 2 7 Design requirements 2 8 Quality control 9 9 Installation 9 Annex A (informative) Characteris
8、tics of gully tops and manhole tops for which requirements are given in BS EN 124 and/or additional guidelines are given in BS 7903 10 Tables 1 Comparison of classification 1 2 Recommended minimum use within the highway 2 3 Minimum nominal widths and waterway areas 4 4 Recommended frame depths 7 5 K
9、erb type gully covers and frames 9 A.1 Characteristics of gully tops and manhole tops for which requirements are given in BS EN 124 and/or additional guidelines are given in BS 7903 10 Figures 1 Single triangular cover over rectangular structure 3 2 Distribution of waterway area 5 3 Keyways and keys
10、 6 4 Typical sealing of manhole tops 7 5 Examples of bedding width 8 6 Webs/gussets 8 List of references Inside back coverii BSI 1997 BS 7903 : 1997 Foreword This British Standard has been prepared by Subcommittee B/505/4. It is to be used in conjunction with BS EN 124 : 1994 Gully tops and manhole
11、tops for vehicular and pedestrian areas Design requirements, type testing, marking, quality control, which superseded BS 497 : Part 1, withdrawn in June 1995. This standard is not a substitute for BS EN 124. Although BS EN 124 purports to be a performance standard, it is not yet comprehensive enough
12、 in its requirements for product performance. It also incorporates certain minimal dimensional requirements which, being minimal, may not necessarily ensure that the product is fit for its purpose in all traffic conditions. The publication of BS EN 124 has resulted in a wider selection of products b
13、eing available, and this standard has been prepared as an aid to those who select or use these products. When quoting BS EN 124 in contract, additional information will be required to obtain the appropriate product, and a table of purchasers options is shown in annex A. BS EN 124 : 1994 requires man
14、datory third party assessment and certification, and unless a product carries a third party certification mark it will be deemed not to conform. The published UK view is that whilst third party certification may be recommended in a standard, it should not be a mandatory aspect of a product specifica
15、tion. This view is now supported by CEN policy, which requires that a CEN Technical Board dispensation be granted before mandatory third party certification is included in a standard. The European committee responsible for revising EN 124 will seek such a dispensation if is decided to retain this re
16、quirement. 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 10, an inside back cover and a back cover. BSI 1997 1 BS 7903 : 1997 Guide 1 Scope This B
17、ritish Standard gives guidance on the selection of gully tops and manhole tops with a clear opening measuring up to 1000 mm as specified in BS EN 124 : 1994 for installation within the highway. 2 References 2.1 Normative references This British Standard incorporates, by dated or undated reference, p
18、rovisions from other publications. These normative references are made at the appropriate places in the text and the cited publications are listed on the inside back cover. For dated references, only the edition cited applies; any subsequent amendments to or revisions of the cited publication apply
19、to this British Standard only when incorporated in the reference by amendment or revision. For undated references, the latest edition of the cited publication applies, together with any amendments. 2.2 Informative references This British Standard refers to other publications that provide information
20、 or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, but reference should be made to the latest editions. 3 Definitions For the purposes of this British Standard, the definitions given in BS EN 124 apply, together with the fo
21、llowing. 3.1 area of waterway The area of a gully grating through which water can pass. 3.2 ductile iron Spheroidal or nodular graphite cast iron. 3.3 highway Area that includes some or all of the following features: carriageway, cycleway, footway, verge, hard shoulder, hard strip and central reserv
22、ation. 3.4 specifier Person who has responsibility for the design and/or maintenance of works, or is responsible for ordering the product. 3.5 fine cast A fettled casting without any coating. 3.6 grey iron Flake graphite cast iron. 3.7 keyway A hole in the top of the manhole cover suitable for the i
23、nsertion of an appropriate lifting key. 3.8 clear area The maximum unobstructed area through the frame (including the area between seats). 4 Classification Manhole covers and gully gratings previously made in accordance with BS 497 : Part 1 (withdrawn) were graded in relation to the test load. Howev
24、er, in that standard the sizes of the test blocks used for manhole covers were different to the sizes of the blocks used for gully gratings. BS EN 124 uses a common classification system for all products, but the test block sizes are different to those used in BS 497 : Part 1. A direct comparison be
25、tween BS 497 : Part 1 grades and BS EN 124 classes is therefore not possible due to the different testing regimes. A broad comparison is set out in table 1. Table 1. Comparison of classification BS EN 124 BS 497 (withdrawn) Class Test load (all materials) Grade Test load kN kN C1 0 A1 5 1 5 B 125 12
26、5 B 150 C 250 250 A 350 D 400 400 D 400 E 600 600 F 900 900 5 Place of installation (See clause 5 of BS EN 124 : 1994.) The selection of the appropriate class of product to suit the site conditions is the responsibility of the specifier. Guidance on recommended usage in the United Kingdom is given i
27、n table 2. NOTE. Where there is any doubt, a stronger class should be selected.2 BSI 1997 BS 7903 : 1997 Table 2. Recommended minimum use within the highway BS EN 124 classification Recommended usage in United Kingdom Group Class Place of installation 1 Min. A 15 Areas which can only be used by pede
28、strians and pedal cyclists. As BS EN 124 2 Min. B 125 Footways, pedestrian areas and comparable areas, car parks or car parking decks. As BS EN 124, with slow moving cars and vehicles up to 3.5 tonnes gross vehicle weight. 3 Min. C 250 For gully tops installed in the kerbside channels of roads (see
29、figure 9a of BS EN 124 : 1994), which, when measured from the kerb edge, extend a maximum of 0.5 m into the carriageway and a maximum of 0.2 m into the footway. a) Slow moving normal commercial vehicles e.g. residential roads where speed is limited. b) Kerb type gullies 4 Min. D 400 Carriageways of
30、roads (including pedestrian streets), hard shoulders (see figure 9b of BS EN 124 : 1994) and parking areas for all types of road vehicles. As BS EN 124 6 Materials 6.1 General BS 497 : Part 1 limited materials to either grey and ductile cast iron or cast steel. BS EN 124 permits a greater choice of
31、materials for use in the highway. When considering the choice of materials offered by manufacturers, the specifier is advised to consider the long-term performance and maintenance implications of products made from other materials. 6.2 Other materials (See 6.1.3 of BS EN 124 : 1994.) It should be no
32、ted that BS EN 124 does not fully specify the requirements for the other materials that it allows. In permitting other materials, it requires conformity to the specification and any other relevant requirements and testing methods to be established by an approved independent body, without defining th
33、e qualifications or standing of such a body. NOTE. BSI is in the process of establishing a Product Assessment Specification (PAS) to allow approval and marking of products manufactured from plastics materials that in all other respects conform to BS EN 124. 6.3 Coatings With the exception of the gal
34、vanizing (see ISO 1461) of units made from rolled steel, there is no specification in BS EN 124 for protective coatings, and cast iron units may be supplied as fine cast. Any coatings required for decorative or other purposes may be specified but it should be noted that short term coatings offer no
35、lasting product enhancement and that any surface oxidization of the cast iron has no detrimental effect upon its use. 7 Design requirements 7.1 Size and shape (See 7.15 of BS EN 124 : 1994.) The shape of the supporting structure immediately below the frame in most engineering situations is rectangul
36、ar or circular, and the specifier should therefore select a manhole top or gully top with a bedding area shape that is appropriate. Irrespective of the exposed shape of the cover/grating, the effective bedding area should be determined so that the specifier can be assured that there is sufficient fr
37、ame bearing area for the proposed application. For any area of unsupported frame (see figure 1), the specifier should establish that there is sufficient strength to carry the expected loads. BS EN 124 does not require this part of the frame to be subjected to any direct test loads. In the single tri
38、angular design, for example, (shown in figure 1) the carriageway above the unsupported part of the frame has been recognized for many years in the United Kingdom as being the area which shows early road surfacing failure. This may in turn lead to a failure of the frame bedding. BSI 1997 3 BS 7903 :
39、1997 Figure 1. Single triangular cover over rectangular structure 7.2 Vents in covers for manhole tops (See 7.2 of BS EN 124 : 1994.) A maximum vent area is not specified. The specifier should refer to the corresponding clause in BS EN 124 : 1994 and the note at the end. 7.3 Clear opening of manhole
40、 top for man entry (See 7.3 of BS EN 124 : 1994.) BS EN 124 requires the opening of manhole tops designed for man entry to conform to safety requirements in force at the place of installation, and points out that these generally require a diameter measuring at least 600 mm. In the United Kingdom the
41、 following dimensions are recommended, in accordance with the safety guidelines published by the National Joint Health and Safety Committee for the Water Service 5: a) the minimum clear opening for a frame with a rectangular opening should be 600 mm with a diagonal measurement of not less than 700 m
42、m; b) the minimum clear opening for a frame with a circular opening should be a diametric measurement of not less than 700 mm; c) the minimum clear opening for a frame with a triangular opening should be a diametric measurement of not less than 700 mm. 7.4 Depth of insertion The depth of insertion i
43、s linked with securing the cover and is dealt with in 7.7. 7.5 Seatings (See 7.6 of BS EN 124 : 1994.) BS EN 124 requires that units of class D 400 to F 900 be manufactured so as to ensure their stability and quietness in use. It is recommended that the specifier extend this requirement to include c
44、lass C 250 manhole covers where these are specified for use in the carriageway. One of the methods suggested to achieve quietness in use is the inclusion of cushioning inserts. However, BS EN 124 does not specify the materials to be used or the performance characteristics required of these inserts.
45、NOTE. There is no widespread public authority experience of cushioning inserts in the United Kingdom. The specifier should satisfy himself about maintenance implications when deciding the methods to be used to achieve quietness in use. 7.6 Coupling of sections Where the quietness in use feature is a
46、chieved by the use of three point suspension, and two triangular units are used to produce a rectangular cover or grating, then the specifier should be assured that their security within the frame is maintained. This may be ensured either by the units being loosely and permanently coupled together o
47、r by some other design feature. The specifier should be assured that any loose couplings are of steel or ductile iron which cannot be over-tightened or detached without the use of a tool. Any nut and bolt supplied as a loose coupling should not be less than size M16. Any alternative steel coupling s
48、hould have a minimum cross- sectional area of 140 mm 2 . A performance requirement of any loose coupling is that it should not be able to vibrate freely during its service life. 7.7 Securing the cover/grating within the frame (See 7.8 of BS EN 124 : 1994.) In the United Kingdom, designers have used
49、several features to ensure the stability of the cover within the frame. These include the mass of the unit, the tightness of fit and the depth of the insertion of the cover into the frame.4 BSI 1997 BS 7903 : 1997 When using class D units, and where the design relies upon the depth of insertion for the security of the cover/grating within the frame, then the depth of the cover/grating immediately adjacent to the frame should be not less than 80 mm. BS EN 124 suggests locking devices may be used to ensure security but does not give any specification. 7.8 Slot dimens
