1、BRITISH STANDARD BS8303-3: 1994 Installation of domestic heating and cooking appliances burning solid mineral fuels Part 3: Recommendations for design and on site installation IMPORTANT NOTE. Before reading this Part it is essential to read BS8303-1: Specification for the design of installations and
2、 BS 8303-2: Specification for installing and commissioning on-site, issued separately.BS8303-3:1994 This British Standard, having been prepared under the directionof the Engineering SectorBoard, was published underthe authority of the Standards Board and comes intoeffect on 15 January 1995 BSI 02-19
3、99 First published, as CP403, August1952 Second edition, October 1974 Third edition, as BS8303, June1986 Fourth edition, January 1995 The following BSI references relate to the work on this standard: Committee reference RHE/28 Draft for comment 91/82857 DC ISBN 0 580 22713 8 Committees responsible f
4、or this British Standard The preparation of this British Standard was entrusted by the Engineering Sector Board to Technical Committee RHE/28, upon which the following bodies were represented: Association of British Solid Fuel Appliance Manufacturers British Ceramic Tile Council British Coal Corpora
5、tion Consumer Policy Committee of BSI Department of Energy (Energy Efficiency Office) Department of the Environment HETAS Ltd. Incorporated Association of Architects and Surveyors Low Temperature Coal Distillers of Great Britain Ltd. METCOM National Fireplace Manufacturers Association National Socie
6、ty for Clean Air Real Fire Association Solid Smokeless Fuels Federation Waterheater Manufacturers Association Coopted members Amendments issued since publication Amd. No. Date CommentsBS8303-3:1994 BSI 02-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definiti
7、ons 1 3 References 1 4 Chimney connection for free standing appliances 1 5 Securing an appliance 1 6 Air inlets 1 7 Sealing of joints 2 8 Flue size 3 9 Separation from combustible material 3 10 Noise 8 11 Energy economy and heat retention 8 12 Alternative flue pipe construction 8 13 Gas ignition 9 1
8、4 Firebacks and infill 9 15 Testing an installation 9 Figure 1 Typical flue connection of a freestanding cooker or independent boiler 2 Figure 2 Dimensions of a fireplace recess 4 Figure 3 Dimensions of a constructional hearth 5 Figure 4 Combustible material under hearth 5 Figure 5 Positioning of ap
9、pliance on a hearth 6 Figure 6 Distance of an appliance from combustible material 6 Figure 7 Separation of a flue pipe from combustible material 7 Table 1 Composition proportions for in-fill 9 List of references Inside back coverBS8303-3:1994 ii BSI 02-1999 Foreword This Part of BS8303 has been prep
10、ared under the direction of the Engineering Sector Board and together with BS8303-1 and BS8303-2 supersedes BS8303:1986 which is withdrawn. BS8303 covers the installation of domestic heating and cooking appliances burning solid mineral fuel. BS8303-1 details the design specification to be followed b
11、y the installation designer, when developing an acceptable appliance installation design for the particular application. BS8303 specifies the practices to be followed when installing the appliance in accordance with the design specification. It reflects good site supervision and working practices. T
12、his Part of BS8303 gives guidance to the designer and installer on options to be identified and the methods of achieving a safe and satisfactory installation. BS8303 does not deal with design or installation of hot water heating systems or hot water supply systems. However, where the appliance invol
13、ves hot water services, attention is drawn to BS5449:1990. Attention is drawn to the need to ensure compliance with all local and general regulations as they affect the installation, including the following: A British Standard does not purport to include all the necessary provisions of a contract. U
14、sers of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. planning permission; Building Regulations 1; Clean Air Act 2; Gas Safety (Installation and Use) Regulations 3. Summary of pages This
15、document comprises a front cover, an inside front cover, pages i and ii, pages1to 10, 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 theinside front cover.BS8303-3:1
16、994 BSI 02-1999 1 1 Scope This Part of BS8303 gives guidance and recommendations on the design and installation of domestic heating and cooking appliances burning solid mineral fuels designed in accordance with BS8303-1:1994 and installed in accordance with BS8303-2:1994. 2 Definitions For the purpo
17、ses of this Part of BS8303, the definitions given in BS1846-1:1994 apply. 3 References 3.1 Normative references This Part of BS8303 incorporates, by dated or undated reference, provisions from other publications. These normative references are made at the appropriate places in the text and the cited
18、 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 to this Part of BS8303 only when incorporated in it by amendment or revision. For undated references, the latest edition a
19、pplies, together with any amendments. 3.2 Informative references This Part of BS8303 refers to other publications that provide information 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 th
20、e latest editions. 4 Chimney connection for free standing appliances Where a freestanding appliance is to be installed without the use of a fireplace recess no part of the chimney should be supported by the appliance. This is neccessary so that if an appliance needs to be removed for any reason it c
21、an be achieved without major disturbance to the chimney. Masonry chimneys can be built up from ground level, a fireplace recess or part of the wall structure of the building. The connection between the appliance and the chimney is achieved via a flue pipe entry either vertically from underneath Figu
22、re 1a) or into an opening in the side of the flue Figure 1b) or Figure 1c). A factory made chimney is commonly supported on ceiling joists. In this case care should be taken that the length of chimney below the lowest support is correctly secured to the section above it and not allowed to rest on th
23、e appliance or any flue pipe. 5 Securing an appliance The appliance should be secured to prevent movement which could cause joint separation at the flue pipe or chimney connection, and for open fires, at the hearth and fire surround. Joint separation could result in leakage of air into the flue or a
24、llow combustion products to escape into the building. Securing is particularly important where an appliance relies for its connection to the flue on a seal between the appliance and the fireplace recess to prevent any leakage. Movement of the appliance can occur for a variety of reasons such as vigo
25、rous operation of the de-ashing mechanism or thermal expansion and contraction. The manufacturers recommendation for fixing should be followed. The most common method is to secure the base of the appliance to the hearth using rag bolts or screws into non-combustible plugs. 6 Air inlets The combustio
26、n air inlet sizes specified in 5.3 of BS8303-1 are the minimum that are required. Open fires require more air than closed appliances because of the additional air that enters the appliance above the firebed. The air is needed for secondary combustion and to prevent flue gas spillage from the fire. T
27、he throat created by the fireback and throat lintel are specially shaped to assist the flow into the flue. The size of the combustion air inlets takes into account the fact that rooms are not usually airtight even when all doors and windows are closed. Consequently there is no requirement to have an
28、 air inlet for closed appliances with an output less than5kW, as enough adventitous air is usually available for satisfactory operation. The ideal position for the air inlets is adjacent to the fireplace recess. Where it is not desirable to provide inlets from outside directly to this location so as
29、 to avoid cold draughts, a suitable place of entry is into an unoccupied area such as the hall. In this way there is an element of preheating of the air before it enters the living areas. Apertures of at least the size specified in 5.3 of BS8303-1 should be provided in partitions between the air inl
30、et and the appliance in order to allow an unrestricted route for the air to reach the appliance.BS8303-3:1994 2 BSI 02-1999 Some appliances are designed for use with underfloor air supplies ducted to the fire. The useofthe underfloor system of ducting may also besuitable for other fires. Where ducti
31、ng cannot readily be provided within or under a floor an alternative technique is to duct air from the roof space. Where this ducting passes through other parts of the house, it should be installed in a mannerthat provides a rated resistance to the spread of fire (see 5.2 of BS8303-1) appropriate to
32、the application; in single occupancy dwellings,materials having a 30minute ratingisusual, indwelling containing flats (multiple occupancy) 90minutes may be required. Open fires tend to induce considerable air changes in the room and, to minimize this effect, it is recommended that provision be made
33、for restricting the throat. This may be done with an insertable throat restrictor conforming to BS3376:1991. Other forms of adjustable throat may be used provided that this allows for flue sweeping. 7 Sealing of joints For a successful installation, joints should be sealed in order to prevent the in
34、gress of unwanted air into the chimney and to reduce the risk of combustion products escaping into living areas, and, in the case of an open fire, to ensure that control of combustion is possible. In most instances the seal can be made with the use of a soft, flexible non-combustible rope or tape of
35、 thicknes suitable for the size of gap which it needs to fill. The rope must be well tamped into the gap but be flexible enough to allow some movement of the joint due to expansion and contraction. The rope can be held in place with a covering of fire cement. This technique is especially recommended
36、 for jointing the flue pipe to the appliance, the raft lintel or register plate. In the latter cases the joint could benefit from the use of a clamping ring which squeezes the rope against the face. Some manufacturers supply a purpose-made flue pipe for this which has lugs with screws to apply the p
37、ressure on the clamping ring and hence the rope. Figure 1 Typical flue connection of a freestanding cooker or independent boilerBS8303-3:1994 BSI 02-1999 3 Special attention should be given to ensuring the presence of a flexible seal around the ashpit area of an open fire. This includes the base whe
38、re the fire sits on the hearth as well as the side of the fire where it meets the fireplace surround. Where a flue pipe enters a chimney through a hole in the chimney wall it is neccessary to sleeve the hole and seal the flue pipe into the sleeve. This may be achieved by cementing in a short length
39、of metal pipe with an inside diameter at least 25mm larger than the outside diameter of the flue pipe. Both ends of the sleeve should be cut to the angle formed with the chimney. The space between the flue pipe and the sleeve should be well caulked with several turns of soft non-combustible sealing
40、rope or other suitable heat resisting material and well tamped in. It is important that the sleeve and the flue pipe do not project inside the chimney flue (seeBS8303-1:1994, Figure 8). This is to avoid the accumulation of fly ash. 8 Flue size The flue sizes for the various categories of appliance a
41、re given in Table 1 of BS8303-1; these are the minimum sizes that should be used on a universal basis for the successful operation of a solid fuel appliance. In general the size of flue is chosen to ensure adequate evacuation of combustion products. The major operating force providing the flue draug
42、ht to evacuate the products of combustion is the buoyancy of the flue gases which is mainly dependent upon the temperature of the flue gas itself but also upon the height of the chimney. An open fire generates a considerably larger volume of flue gas than a closed appliance and therefore needs a big
43、ger capacity flue. In addition the flue gas temperature from an open fire is considerably less than a closed appliance and therefore the buoyancy (or flue draught) is also less. Where a chimney is particularly tall, and to prevent excessive draught as may be the case in multi-storey houses, then it
44、may be neccessary to fit a flue draught stabilizer. It is essential that this device is fitted in the same room or space as the appliance. 9 Separation from combustible material 9.1 Fireplace recess Care should be taken to prevent combustible materials being damaged or ignited when they are subjecte
45、d to heat from any of the causes described in5.4 of BS8303-1. In the case of a fireplace recess the walls should be of sufficient thickness to prevent the temperature of adjacent combustible material from reaching in excess of 100 C. The thickness will depend on the insulating property of the materi
46、al of construction. For traditional brick or concrete block construction the dimensions given in Figure 2 should be adopted. 9.2 Hearth A hearth should be constructed from solid, non-combustible material at least 125mm thick (this dimension may include the thickness of any solid, non-combustible flo
47、or under a hearth but excluding the thickness of any added decorative finish). Its dimensions should be at least those shown in Figure 3 a) for appliances installed into a fireplace recess, or at least those shown in Figure 3 b) for freestanding appliances. Combustible material should not be placed
48、under a hearth unless: a) it is to support the edges of the hearth; or b) there is an air space of at least 50mm between the material and the underside of the hearth, or there is a distance of at least 250mm between the material and the top of the constructional hearth (see Figure 4). When the surfa
49、ces of the appliance are such that any adjacent combustible materials will not exceed100C e.g. where the appliance is surrounded by a boiler then the provisions of Figure 4 for a hearth are not required. However when a change of appliance occurs the suitability of the hearth should be confirmed. A hearth is a neccessary part of the installation of an appliance not only for protection of combustibles from the heat transmitted directly from an appliance but also to prevent damage resulting from hot ash or embers falling from it. For this reas
