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1、BRITISH STANDARD BS 5502-74: 1991 Buildings and structures for agriculture Part 74: Code of practice for design and construction of bins and silos for combinable crops Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 14:39:46 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5502-74:1991 This Brit
2、ish Standard, having been prepared under the direction of the Technical Sector Board for Building and Civil Engineering (B/-), was published under the authority of the Standards Board and comes into effect on 20 December 1991 BSI 03-1999 The following BSI references relate to the work on this standa
3、rd: Committee reference B/549 Draft for comment 90/14591 DC ISBN 0 580 20257 7 Committees responsible for this British Standard The preparation of this British Standard was undertaken by Technical Committee B/549, upon which the following bodies were represented: British Cement Association British C
4、ommercial Glasshouse Manufacturers Association British Precast Concrete Federation Ltd. British Veterinary Association Department of Agriculture Northern Ireland Farm and Rural Buildings Centre Farm Buildings Association Health and Safety Executive Institution of Civil Engineers Ministry of Agricult
5、ure, Fisheries and Food National Farmers Union Royal Institute of British Architects Royal Institution of Chartered Surveyors Scottish Office (Agriculture and Fisheries Department) Steel Construction Institute Transport and General Workers Union Water Services Association of England and Wales Amendm
6、ents issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 14:39:46 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5502-74:1991 BSI 03-1999i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2Definitions1 3General1 4Design, materi
7、als and construction1 5Environment4 6Services6 7Fire precautions, safety, welfare and hygiene7 8Safety signs and notices7 Index8 Table 1 Bulk densities (for determining volumes)3 Table 2 Angle of repose for crops3 Table 3 Slopes for crop flow3 Table 4 Recommended storage period for grain at or below
8、 16 C and at various moisture contents4 Table 5 Equilbrium moisture content and relative humidity for wheat and barley4 Table 6 Maximum drying temperature for grain4 Table 7 Maximum air temperature for 90 % germination of grass seeds5 Table 8 Maximum storage of wheat with respect to germination5 Tab
9、le 9 Ventilation rates5 Table 10 Air velocity5 Table 11 Maximum air speeds5 Table 12 Resistance to airflow (in Pascals) per metre depth of crop6 Table 13 Temperature for chilled storage of grain6 Publication(s) referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 14:39
10、:46 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5502-74:1991 ii BSI 03-1999 Foreword This Part of BS 5502 has been prepared under the direction of the Technical Sector Board for Building and Civil Engineering. It comprises a new Part to BS 5502. While BS 5502 is being revised and added to, the opp
11、ortunity is being taken to restructure the standard into the following broad subject areas: Part 0: Introduction and consolidated index; Parts 10 to 19: Reference information and legislation; Parts 20 to 39: General design; Parts 40 to 59: Livestock buildings; Parts 60 to 79: Crop buildings; Parts 8
12、0 to 99: Ancillary buildings. More specifically, the crop building series will comprise: Part 60: Code of practice for design and construction of buildings for mushrooms; Part 65: Code of practice for design and construction of crop processing buildings; Part 66: Code of practice for design and cons
13、truction of chitting houses; Part 70: Code of practice for design and construction of ventilated on floor stores for combinable crops; Part 71: Code of practice for design and construction of ventilated stores for potatoes and onions; Part 72: Code of practice for design and construction of cool sto
14、res; Part 74: Code of practice for design and construction of bins and silos for combinable crops. A more detailed description of the new structure of BS 5502 is given in Part 0. The object of introducing the new structure is to allow subject areas to be broadly characterized, and related subject ma
15、tter, whether in the form of recommendations, guidance or supporting data, to be rationalized and brought together. It will also allow sufficient flexibility to enable BS 5502 to be expanded and developed in a logical way in the future. It has been assumed in the drafting of this Part of BS 5502 tha
16、t the execution of its provisions is entrusted to appropriately qualified and experienced people, for whose guidance it has been prepared. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct applicati
17、on. 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 8, an inside back cover and a back cover. This standard has been updated (see copyright date) an
18、d may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 14:39:46 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5502-74:1991 BSI 03-19991 1 Scope This Part of BS 5502 gives recommendations
19、for the design and construction of bin and silo systems for storing combinable crops. NOTE 1For on floor storage see BS 5502-70. NOTE 2The titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this standard, the definitions giv
20、en in BS 6100 apply. 3 General 3.1 Storage The function of crop storage structures is maintenance of crop quality by control and retardation of the natural biological processes of the crop. The quality is maintained by controlling storage temperatures and relative humidity. Drying usually precedes s
21、torage by the application of heat from a continuous flow or batch bin drier. Alternatively, drying can take place within the bin/silo itself. 3.2 Siting Consideration should be given to the siting of crop stores (see BS 5502-20). In particular, consideration should be given to the following: a) choo
22、sing a level site where there is no risk of flooding; b) choosing ground with adequate bearing capacity; c) ease of access for large transport; d) availability of services; e) nuisance arising from transport, machinery noise and the creation of dust; f) allowing for future expansion. 3.3 Type of sto
23、rage 3.3.1 The design of bins and silos will be determined by the following factors: a) type of produce stored; b) storage duration; c) drying system employed; d) sophistication of the mechanical handling; 3.3.2 Crops may be either: a) pre-dried and stored in a bin with sufficient ventilation to kee
24、p the crop conditioned; b) dried in a bin linked to a drying fan. 3.3.3 Bins/silos can be round or square with flat or hopper bottoms. Positioning may be in a semi-circle or in a single or double line format. The storage may be located in the open or under a roof. In either case, the units should be
25、 linked to a pit with an elevator and conveyor system. Bins can be positioned in existing buildings. 4 Design, materials and construction 4.1 General 4.1.1 The design, choice of materials and construction of bins/silos for crops should be in accordance with BS 5502-20, BS 5502-21, BS 5502-22, BS 550
26、2-23 and BS 5502-25. 4.1.2 Foundations and support structures for bin and silo stores should be designed and constructed to withstand loads from the stored crops and equipment. 4.1.3 Structures should be designed to minimize differential settlement, deflection and structural movement that could caus
27、e fracturing of surfaces and permit moisture ingress or infestation, so putting the stored products at risk. 4.1.4 Store interiors require cleaning or fumigation after the storage period and this should be considered in the choice of materials. 4.1.5 Materials and treatments used in the construction
28、 should not impart odour or taint to the crop. 4.1.6 All parts of the structure should be constructed in accordance with the recommendations given in BS 8000. 4.2 Floors Floors should be level with an even surface. Floors should be designed and constructed to withstand the load from the crops, plant
29、 and equipment. The surface should be hard wearing, capable of being cleaned and not susceptible to cracking or crazing. To prevent moisture ingress to the crop, a damp-proof membrane should be provided. Thermal and shrinkage movement should be minimized by the correct placing of construction, expan
30、sion and contraction joints. 4.3 Walls The material for bin/silo construction will vary according to the location. Bins to be used externally should be weatherproof and be covered. Where bins/silos are positioned inside a building, weatherproofing is not required and bins do not require a top. Licen
31、sed Copy: sheffieldun sheffieldun, na, Mon Dec 04 14:39:46 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5502-74:1991 2 BSI 03-1999 4.4 Roof and wall cladding Bins/silos may support their own roof/cover or the roof/cover may be independent; in either case the roof/cover should be fixed so as to prev
32、ent entry of rain and driven snow. Louvred outlets should be provided at high level for ventilation. Consideration should be given to the exclusion of natural light in order to discourage birds and to the screening of ventilators to keep out birds and vermin. 4.5 Doors Where bins/silos are uncovered
33、 within a roofed structure, doors should be fitted to the structure to protect equipment from the weather and to prevent infestation. The door dimensions and position should be determined by the layout and use of the store. An opening of 4.5 m 4.5 m should normally be used, but larger access may be
34、required. Personnel doors and emergency escape doors should be included. Provision should be made for securing side-hung doors when open to prevent damage by high winds. The door threshold should be designed to keep out water. The external access area should slope away from the doorway. 4.6 Receptio
35、n pits 4.6.1 Reception pits should be self-emptying and should be designed to hold the required tonnage of crop relative to the throughput of the system. Where ground conditions restrict the size, a powered intake should be considered. Sloping surfaces should be not less than 45 from the horizontal.
36、 Pits should incorporate a damp-proof membrane or, where the water table is likely to rise above base level, they should be constructed either using concrete which is fully waterproof or with a fully anchored waterproof lining. The top of the pit should be fitted with a grille to act as a safety gua
37、rd which should be designed to support the discharging machinery, if required. 4.6.2 Pits not designed to support vehicles should have a 300 mm high kerb along the edge that would be approached by vehicles. 4.7 Elevator pits Elevator pits should be constructed large enough to provide access to eleva
38、tors for maintenance, repair and replacement. Pits should incorporate a damp-proof membrane or, where the water table is likely to rise above base level, they should be constructed either using concrete which is fully waterproof or with a fully anchored waterproof lining. A fixed ladder and lighting
39、 should be provided. The pit cover should permit access and should be designed to carry at least the minimum floor loading (see BS 5502-22). 4.8 Grain conveying The delivery rate of the harvesting and handling equipment should be balanced to ensure a compatible and efficient flow. Discharge conveyor
40、s should spread the grain evenly to avoid the formation of compaction and/or separation columns. NOTE 1This rate is determined from the capacity of the combined-harvester/tractor-trailer capacity and the capacity of the intake pit at the store. NOTE 2The capacity of elevators and conveyors should be
41、 greater than the maximum discharge rate from the drier. Overhead hoppers for filling of lorries should be able to refill between arrivals of lorries. 4.9 Ventilation ducts The floor of a bin should be perforated or should contain lateral ducts within the structure to permit the bin to be ventilated
42、. Alternatively, perforated ducts may be positioned above the floor. Care should be taken when sizing the perforations to ensure the free surface area is not blocked by the stored crop. Where oilseed rape is to be dried, the ventilating holes should be not greater than 1.5 mm diameter. NOTE 1Ventila
43、tion ducts, if so designed, can be used for air sweep purposes when emptying the bins/silos. NOTE 2Radially ventilated bins are cylindrical with air-permeable walls. Air is introduced via a radial plenum linked to a fan. 4.10 Fan housing Fans for individual isolated external bin systems can be perma
44、nent or transportable and are fixed adjacent to the bin, requiring no housing except for weather protection. For integrated internal nested bins/silos fans may be housed inside the store, but preferably they should be housed in a structure built externally. Louvred inlets or top-hung airdoors should
45、 be provided to ensure the unrestricted access of air to the fan. The openings should be screened to keep out birds and pests. Nuisance due to noise levels should be prevented by insulation, increasing mass and correct siting. 4.11 Access and walkways Crop storage installations should include all wa
46、lkways, stairs and platforms necessary to allow safe access to areas for loading and unloading, for inspection of the crop during storage and for cleaning out and maintenance. Handholds should be provided at the top of all ladders, and ladders should be fixed. Parapet rails and kicker boards should
47、be provided to all areas where access is provided. Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 14:39:46 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5502-74:1991 BSI 03-19993 4.12 Store geometry 4.12.1 General dimensions The following factors should be considered when determining the dim
48、ensions of bin/silo stores for crops: a) volume of stored crop; b) need for a uniform ventilation rate throughout the stack; c) space required for loading and unloading; d) space required for equipment; e) management techniques. 4.12.2 Store layout The store layout should allow the efficient flow of
49、 the crop through the system from field to store and subsequently from store to sale. There should be access to all parts of the store, where necessary, for maintenance and repair. The level of the reception pit in relation to the ground should be considered. 4.12.3 Bulk density of stored crops When determining storage volumes, bulk densities as given in Table 1 should be used. Under certain conditions these figures can be exceeded. Table 1 Bulk densities (for determining volumes) 4.12.4 Angle of repose Where the crop i
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