1、BRITISH STANDARD CP 342-2:1974 Code of Practice for Centralized hot water supply Part 2: Buildings other than individual dwellings UDC 696.4:697.4CP342-2:1974 This Code of Practice has been prepared by a Committee convened by the Codes of Practice Committee for Building. It was published under the a
2、uthority of the Executive Board on 31 October 1974 BSI 07-1999 First published February 1950 First revision Part 2 published October 1974 The following BSI references relate to the work on this Code ofPractice: Committee reference BLCP/38 Draft for comment 72/11172 DC ISBN 0 580 08300 4 Code draftin
3、g committee BLCP/38- Hotwater supply A British Standard does not purport to include all the necessary 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. Summ
4、ary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 24, 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 f
5、ront cover. Chairman Mr D L Mumford British Gas Corporation Mr J V Sutton |Mr A B Baldwin British Waterworks Association |Mr J S W Bath |Miss N C Popkin Department of the Environment |Miss P R Tindale Department of Health and Social Security Mr D L Mumford Domestic Solid Fuel Appliance Approval Sche
6、me Mr R J Godliman Federation of Associations of Specialist and Sub-Contractors Mr P A Curtis Greater London Council Mr R J Dickson Heating and Ventilating Contractors Association Mr P D Emes Institution of Gas Engineers Mr J V Sutton National Coal Board Mr C E Knight Amendments issued since publica
7、tion Amd. No. Date of issue CommentsCP342-2:1974 BSI 07-1999 i Contents Page Code drafting committee Inside front cover 0 Introduction 1 1 General 1.1 Scope 1 1.2 Definitions 1 1.3 Exchange of information 2 1.4 Programming 3 2 Materials, appliances and components 2.1 British Standards 3 2.2 Boilers
8、3 2.3 Combined boiler and cylinder units 4 2.4 Materials for boilers, and internal treatment 4 2.5 Boiler mountings 4 2.6 Flue pipes 4 2.7 Tools for cleaning and maintaining boilers 4 2.8 Calorifiers 4 2.9 Calorifier mountings 4 2.10 Hot water storage vessels 5 2.11 Hot water storage vessel mounting
9、s 5 2.12 Cold water feed cisterns 5 2.13 Pipes and pipe fittings 5 2.14 Electric immersion heating elements 5 2.15 Valves 6 2.16 Taps 6 2.17 Towel rails 6 2.18 Electrically driven circulating pumps 6 2.19 Thermal insulation 6 3 Design 3.1 General 7 3.2 Temperatures 7 3.3 Consumption and storage 8 3.
10、4 Particular requirements for individual dwellings 8 3.5 Character of water 8 3.6 Standby plant 8 3.7 Sump pumps 9 3.8 Boilers 9 3.9 Boiler siting 9 3.10 Chimneys and flue pipes 9 3.11 Hot water storage vessels, including storage calorifiers or indirect cylinders 10 3.12 Siting of hot water storage
11、vessels 11 3.13 Safety and fire precautions 11 3.14 Pipework 11 3.15 Discharge rates and probable demand 11 3.16 Pipe sizing data 12 3.17 Primary circuits 12 3.18 Secondary circuits 12 3.19 Draw-off pipes 12 3.20 Cold feed pipe 13CP342-2:1974 ii BSI 07-1999 Page 3.21 Open vent pipe 13 3.22 Automatic
12、 air eliminators and air bottles 14 3.23 Draining 14 3.24 Electrically driven circulating pumps 14 3.25 Extent of insulation work to be undertaken 15 3.26 Mixing valves 15 3.27 Spray taps 15 3.28 Prefabrication 15 4 Work on site 4.1 Cleanliness of installation 16 4.2 Boiler bases 16 4.3 Boiler insta
13、llation 16 4.4 Flue pipe 16 4.5 Storage vessel supports 16 4.6 Pipework installation 16 4.7 Pipe fixings, supports etc. 17 4.8 Vent pipes and venting generally 18 4.9 Draining of system 18 4.10 Joints for galvanized pipes and fittings 18 4.11 Joints for copper pipes and fittings 18 4.12 Joints for s
14、tainless steel pipes 19 4.13 Lead joints to copper and iron 19 4.14 Location of valves 19 4.15 Identification of pipes 19 4.16 Circulating pumps 19 4.17 Thermal insulation 19 5 Inspection, testing and commissioning 5.1 Tests off site 20 5.2 Cleaning and filling 20 5.3 Tests on site 20 5.4 Commission
15、ing 22 6 Maintenance 6.1 General 23 6.2 Planned maintenance 23 Table 1 Maximum permissible lengths of dead legs 7 Table 2 Recommended rates of discharge 11 Table 3 Sizes of open vent pipes 13 Table 4 Intervals between pipe supports 17 Publications referred to 24CP342-2:1974 BSI 07-1999 1 0 Introduct
16、ion 0.1 A centralized hot water supply installation may include the following: 1) a cold water feed cistern with cold water supply connection (see CP 310); 2) a cold water feed pipe from feed cistern; 3) a feed and expansion cistern or pressurizing unit; 4) a. a boiler which may be one of the follow
17、ing types: solid fuel, oil fuel, gas or electric together with a hot water storage vessel; or b. a non-storage calorifier together with a hot water storage vessel; or c. a storage calorifier; 5) a supplementary heating unit; 6) pipework, valves, and draw-off taps; 7) supplementary fittings, e.g. tow
18、el rails; 8) circulating pumps; 9) thermal insulation; 10) automatic controls; 11) electrical equipment, wiring and connections. 0.2 A complete installation may involve a variety of trades, and it is in the interest of safety and good workmanship that work and services applicable to specific trades
19、be confined to such trades. 0.3 Where the main contractor supplies the following services they should be punctually provided when called for: 1) hoisting facilities; 2) supply and erection of scaffolding and ladders; 3) construction of plant bases; 4) cutting away and making good; 5) carpentry and j
20、oinery; 6) decorating and painting; 7) cold water storage cistern with cold water pipes to and from the cistern, also connections to hot water draw-off points from the stopvalve (where provided) for a single fitting and from the outlet tee on the float of a range of fittings; 8) electrical wiring an
21、d connections; 9) temporary artificial lighting and cold water supply for installation purposes; 10) fuel, power and water for testing and for application of thermal insulation. 0.4 Centralized hot water supply installations are to comply with the byelaws of the local water undertaking. 0.5 All elec
22、trical cables and apparatus used for the installation are to be installed in accordance with the current edition of the “Regulations for the Electrical Equipment in Buildings” published by the Institution of Electrical Engineers. 0.6 All gas fired installations are to comply with the requirements of
23、 The Gas Safety Regulations,1972. 0.7 Where applicable the requirements of the following regulations are to be observed: 1) The Building Regulations 1972, applicable in England and Wales except Inner London, 2) The Building Standards (Scotland) (Consolidation) Regulations, 1971. 3) The London Buildi
24、ng Acts 1930 to 1939 and constructional by-laws in force thereunder. Where the expression “compliance with the relevant Building Regulations” is used, it means compliance with the above regulations or any revision currently in force. 1 General 1.1 Scope Part 2 of this Code offers guidance on the des
25、igning, planning, installation, inspection and testing of systems of hot water supply in commercial, industrial or multiple dwelling buildings supplied from a central source, including district or group schemes. Systems for use in individual dwellings are covered in Part 1. This Code does not deal w
26、ith the installation work required for the supply of steam or high pressure hot water to calorifiers (see3.17.2). Non-storage hot water supply appliances are not included in this Code. Reference should be made to CP333 and CP324.202. NOTEThe titles of the British Standards referred to in this Code a
27、re listed on pages 24 and 25. 1.2 Definitions For the purposes of this Code of Practice, the following definitions apply: 1.2.1 automatic air eliminator a self-operating device for automatically releasing air from a water system 1.2.2 battery the internal heating element of a calorifier comprising t
28、ubes, coils or radiator sectionsCP342-2:1974 2 BSI 07-1999 1.2.3 calorifier a heat exchanger in which water is heated by another fluid, generally at pressures in excess of atmospheric, through the medium of an internal heating element 1.2.4 combined system a system supplying space heating and domest
29、ic hot water from a single source 1.2.5 dead leg a length of hot water pipe leading to a draw-off point and not forming part of a circuit 1.2.6 design flow rate the rate of water flow used in the design calculations 1.2.7 direct system a system in which the water supplied to the draw-off points has
30、been directly heated in the boiler 1.2.8 distributing pipe any pipe conveying water from a storage cistern, or from a hot water apparatus supplied from a feed cistern, and under pressure from that cistern or apparatus 1.2.9 draught stabilizer a fitting for limiting the draught in a flue to a predete
31、rmined maximum 1.2.10 fan-diluted flue system a forced draught flue system in which the products of combustion from a gas installation are diluted, normally to a value not exceeding 1% CO 2 , with air taken preferably direct from outside 1.2.11 indirect cylinder a hot water storage vessel in which w
32、ater is stored and heated by means of an internal element through which hot water is circulated in such a manner that it does not mix with the stored water 1.2.12 indirect system a system in which the water supplied to the draw-off points has been indirectly heated in an indirect cylinder or calorif
33、ier 1.2.13 maximum demand the total rate of water flow when all draw-off points are in use simultaneously 1.2.14 mechanical draught the use of a fan, usually electrically driven, to promote the movement of gases passing through the boiler and/or chimney 1.2.15 pressurizing unit a vessel that is conn
34、ected to a hot water system for accommodating increases in volumes due to expansion and/or to provide an adequate pressure 1.2.16 primary circuit a circuit in which water circulates between a boiler or other water heater and a hot water storage vessel 1.2.17 probable demand a rate of flow less than
35、the maximum demand rate based on the number of draw-off points which probably may be in use simultaneously 1.2.18 secondary circuit a circuit in which water circulates from and back to a hot water storage vessel 1.2.19 service pipe so much of any pipe, for supplying water from a main to any premises
36、, as is subject to water pressure from that main, or would be so subject but for the closing of some stopvalve 1.3 Exchange of information 1.3.1 At the planning stage the following matters should be agreed or determined by the installation designer, in consultation, where appropriate, with the build
37、ing designer: 1) fuel to be used; 2) location and dimension of boiler house or calorifier chamber and the plant loads imposed on the structure; 3) location and dimension of fuel store and access; 4) means of ash disposal; 5) location and dimensions of chimney; 6) location of the cold water cistern,
38、having regard to its size in relation to the maximum demand, its elevation as determining the head available, protection against frost and the weight to be supported;CP342-2:1974 BSI 07-1999 3 7) location of pipe runs and the size of all main ducts and trenches; 8) location and sizes of holes for pi
39、pes in the building which have to be preformed, e.g. in the case of prestressed or reinforced structural members; 9) drainage facilities for emptying the installation; 10) character of water supply; 11) details of gas and electricity supply, including location and size of meters; 12) adequate provis
40、ion of air for combustion and ventilation; 13) details of boiler house noise attenuation relative to: a. the plant and equipment b. the structure. 1.3.2 The installation designer should be supplied with scale drawings of the premises including plans and sectional elevations. 1.3.3 The installation d
41、esigner should issue: 1) drawings to scale, indicating the layout of the heating unit, storage vessel, circulating pump, cold water cistern and feed pipe, pipe runs and sizes, drying coils, towel rails, draw-off points, drain points, vent pipes and meters; 2) a full specification of the complete sys
42、tem stating capacities, ratings and conditions of performance to comply with the specific requirements; 3) a schedule of builders work and a set of drawings of builders work; 4) electrical wiring and control diagrams. 1.3.4 The installation contractor should provide and be responsible for all drawin
43、gs relating to special fabrication of pipes and, where so covered by the contract, assemblies of plant items. 1.3.5 The installation contractor should provide record drawings on which all work as installed is clearly shown and a set of operating and maintenance instructions including a list of recom
44、mended spares. 1.4 Programming 1.4.1 The installation of the hot water supply system should proceed in accordance with the general programme of operations for the construction of the entire project. The general programme should be prepared in consultation with all interested trades, as it is desirab
45、le that the installation of the hot water supply should proceed concurrently and in phase with the work of other contractors. Before the installation contractors work is due to commence, space for an adequate lock-up store and workshop accommodation should be provided. Racking for the storage and pr
46、otection of pipes should be provided. The installation contractor should ensure that all builders work necessary to meet the phased progress of the work has been completed. Priority should be given to completion of the boiler house, fuel store and plant room so as to facilitate delivery and erection
47、 of boilers, calorifiers, storage vessels, mechanical stokers and any other heavy plant. Suitable access should be provided. On completion of the installation or sections of the installation, the system should be tested and inspected for water-tightness; thermal insulation should then be applied and
48、 a test carried out under working conditions. 2 Materials, appliances and components 2.1 British Standards All materials, appliances and components used in the work described in this Code should comply with the requirements of the latest edition of any applicable British Standard. Where no British S
49、tandard exists, materials and equipment should be of suitable quality and workmanship and should be open to inspection at the manufacturers works before despatch. The detailed specification of all materials for which there is no British Standard should be available. 2.2 Boilers 2.2.1 Boilers may be classified broadly under two headings: 1) hot water supply boilers which are designed for the direct heating of the water actually drawn off, and 2) hot water supply boilers which are designed for the indirect heating of water actually drawn off. 2.2.2 The British Standar
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