BS 5440-1:2008
$215.11
Flueing and ventilation for gas appliances of rated input not exceeding 70 kW net (1st, 2nd and 3rd family gases) – Specification for installation of gas appliances to chimneys and for maintenance of chimneys
| Published By | Publication Date | Number of Pages |
| BSI | 2008 | 122 |
This part of BS 5440 specifies requirements for the installation of gas appliances to chimneys, chimney installation work likely to be undertaken by gas engineers and operatives working under UK gas industry conditions and requirements for the maintenance of chimneys. It is applicable to open flue chimneys for Type B gas appliances and room-sealed chimney configurations for Type C gas appliances, each of rated input not exceeding 70 kW net (see Note 2 and Note 3), burning 1st, 2nd or 3rd family gases. It applies to chimneys of the natural draught or fanned draught type and is applicable to open flue chimneys and room-sealed chimneys supplied with the appliance as well as to those supplied separately.
NOTE 1 Type B and Type C appliances are explained in Table A.1.
It complements the requirements for the design, installation and commissioning of chimneys as required in BS EN 15287-1 and BS EN 15287-2 and requires extra details that are specific to the UK gas industry. This is kept in perspective by quoting some details of BS EN 15287-1 and BS EN 15287-2.
It specifies the following:
- requirements for the selection of the appropriate flueing option for gas appliances in the UK;
- requirements for the installation of gas appliances to new chimneys, or chimney configurations;
- requirements for the installation of gas appliances to existing chimneys or chimney configurations;
- requirements for the installation of appliances which carry a CE mark and for which the manufacturer’s instructions are available to the installer;
- requirements installation of appliances which do not carry a CE mark and used/second-hand appliances for which the manufacturer’s instructions are available to the installer.
This part of BS 5440 is applicable to:
- complete chimney and all chimney components from the appliance connection to the discharge point into outside air;
- the installation of gas appliances to existing chimneys that were intended originally for appliances burning other fuels;
- chimneys for residential park homes but not to chimneys for leisure accommodation vehicles.
This part of BS 5440 is not applicable to gas-fired incinerators. Refer to BS 5871-3 for the installation of decorative fuel effect appliances.
This part of BS 5440 includes compatibility of appliances installed in the UK with new chimneys designated under BS EN 1443 and with existing chimneys, including non-designated chimneys.
NOTE 2 In the case of an individual appliance connected to a chimney the 70 kW maximum rated input relates to that appliance. In the case of more than one appliance in the same room connected to a single chimney the 70 kW maximum rated input relates to the sum of the rated inputs of all the appliances. In the case of appliances in separate dwellings connected to a shared flue in a chimney, e.g. a SE-duct or a U-duct, the 70 kW maximum rated input relates to the rated input of each individual appliance.
NOTE 3 Installation of LPG (liquefied petroleum gas) systems in leisure accommodation vehicles is specified in BS EN 1949 and further guidance is given in the Institution of Gas Engineers and Managers publication IGE/UP/8 [9].
NOTE 4 Installation of gas-fired hot water boilers having rated inputs exceeding 70 kW is specified in BS 6644.
NOTE 5 The data in this British Standard refers to heat input expressed in terms of net calorific values (CV) with conversion given for natural gas gross CV quoted in brackets where appropriate. The ratio of gross heat input: net heat input is approximately 1.1:1 for natural gas propane and butane. For example, conversion of 9 kW input based on gross CV for natural gas to the equivalent net CV input is as follows: net input = 9.0/1.1 = 8.2 kW.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 3 | Contents 1 Scope 1 2 Normative references 2 3 Terms and definitions 4 4 Competence 9 5 General 9 5.1 Compatibility of appliances and chimneys 9 5.2 Chimney outlets 12 5.3 Chimneys for use with condensing appliances (open-flued and room-sealed) 13 5.4 Location of appliances 14 5.5 Passive stack ventilation 15 5.6 Exchange of information and planning 15 5.7 Maintenance 16 6 Individual open-flued natural draught Types B11, B12, B13 appliances 17 6.1 Design 17 6.2 Installation 31 6.3 Commissioning 34 6.4 Radon gas systems present 38 6.5 Maintenance 38 7 Individual open-flued fanned draught Types B14, B22, B23 appliances and fanned draught chimneys 39 7.1 Design 39 7.2 Installation 41 7.3 Commissioning 41 7.4 Maintenance 42 8 Shared open flue chimney for natural draught Types B11, B12, B13 appliances 42 8.1 Design 42 8.2 Installation 46 8.3 Maintenance 46 9 Room-sealed natural draught chimney configurations (balanced flue) for Type C11 appliances 46 9.1 General 46 9.2 Installation 47 9.3 Installation checks 48 9.4 Maintenance 49 10 Room-sealed: fanned draught chimney configurations balanced flue (for Type C12, C13, C32 and C33) and non-balanced flue (for Type C52, C53, C62 and C63 appliances) 49 10.1 Design options 49 10.2 Installation 50 10.3 Installation checks 53 10.4 Maintenance 53 11 Balanced compartment 55 11.1 General 55 11.2 Design 56 11.3 Balanced compartment construction 56 11.4 Temperature effects 57 11.5 Terminals 57 |
| 4 | 11.6 Commissioning 57 11.7 Maintenance 57 12 Room-sealed Types C2 and C4 appliances for shared chimneys 58 12.1 Selection and installation of a suitable chimney 58 12.2 Terminal design and location 65 12.3 Inspection 66 12.4 Selection and installation of compatible appliances 66 12.5 Commissioning 68 12.6 Maintenance 69 13 Special categories of chimney 70 13.1 Chimneys for Type C7 (“Vertex”) appliances 70 13.2 Other open flue fanned draught chimneys 70 Annexes Annex A (informative) Classifications 72 Annex B (informative) Calculation method for flue sizing 80 Annex C (normative) Chimney outlet positions 86 Annex D (informative) Guidance on the design and installation of flue block systems in the UK 97 Annex E (informative) Checking of case seals and the general integrity of room-sealed fan assisted positive pressure gas appliances 107 Annex F (normative) Design criteria for terminals for shared system chimneys 109 Bibliography 110 List of figures Figure 1 – Typical methods of using a flue liner in a masonry chimney installation serving a gas appliance, other than a back boiler 18 Figure 2 – Installation of a gas fire and combined back boiler using a back boiler enclosure and prefabricated chimney: enclosure arrangement using a false chimney breast and closure panel 19 Figure 3 – Installation of a gas fire and combined back boiler using a back boiler enclosure and prefabricated chimney: enclosure arrangement using a proprietary back boiler box 20 Figure 4 – Maximum lengths for condensate-free chimneys for appliances other than gas fires 25 Figure 5 – Boiler connections to existing brick chimney 30 Figure 6 – Flue block types and shared chimney 45 Figure 7 – Balanced compartment installations 55 Figure 8 – Shared room-sealed systems 61 Figure A.1 – Typical appliances Types A and B, classification to PD CEN/TR 1749:2005 75 Figure A.2 – Typical appliance Types C, classification to PD CEN/TR 1749:2005 76 Figure A.3 – Typical appliance Types C3 and C7, classification to PD CEN/TR 1749:2005 79 Figure B.1 – Worked example 1 84 Figure B.2 – Worked example 2 85 Figure C.1 – Open flue, natural draught chimney outlet locations for pitched roofs 87 Figure C.2 – Open flue, natural draught chimney outlet locations adjacent to structures on pitched roofs 88 |
| 5 | Figure C.3 – Open flue or room-sealed, natural or fanned draught chimney outlet locations adjacent to windows or openings on pitched roofs 88 Figure C.4 – Open flue, natural draught chimney outlet locations on flat roofs 89 Figure C.5 – Open flue, natural draught chimney outlet locations near adjacent structures or buildings 90 Figure C.6 – Room-sealed configuration outlet location on pitched roofs 90 Figure C.7 – Open flue, fanned draught chimney and room-sealed configuration outlet locations adjacent to structures on pitched roofs 91 Figure C.8 – Chimney outlet positions 91 Figure C.9 – Example of how a natural draught, room-sealed chimney configuration outlet position is measured 94 Figure C.10 – Example of how a fanned draught room-sealed chimney configuration outlet and a fanned draught open flue chimney outlet position is measured 95 Figure C.11 – Proximity of flue duct outlet to a boundary 96 Figure D.1 – Gas flue blocks 99 Figure D.2 – Typical flue block systems (general arrangement) 100 Figure D.3 – Bonded gas flue block system for timber frame construction 101 Figure D.4 – Typical construction details for gas flue block systems in internal walls 102 Figure D.5 – Typical construction details for gas flue block systems in external walls 102 Figure E.1 – Checklist for checking of case seals and the general integrity of room-sealed fan assisted positive pressure gas appliances 108 Figure F.1 – Permitted recirculation of combustion products 109 List of tables Table 1 – Condensate-free lengths of individual open flue used with a gas fire 24 Table 2 – Minimum void dimensions required below appliance connections 29 Table 3 – Appliance/chimney combinations which require the chimney to be lined 30 Table 4 – Minimum flow rates for fanned flues 42 Table 5 – Appliances discharging by way of subsidiary flue into a main flue 44 Table 6 – Normal SE-duct block sizes in existing buildings 58 Table 7 – SE-duct sizes for continuously burning appliances (e.g. boilers, gas fires) in flats 59 Table 8 – SE-duct sizes for combinations of instantaneous water heaters (30 kW input rating) and continuously burning appliances (e.g. boilers, gas fires) in flats 60 Table 9 – Cross-sectional area for ducts in shared system chimneys used for condensing and non-condensing appliances (one appliance per storey) 64 Table 10 – Cross-sectional area for ducts in shared system chimneys used for condensing and non-condensing appliances (two appliances per storey) 65 |
| 6 | Table A.1 – Classification of gas appliances used in the UK according to the method of evacuation of products of combustion (types) – from PD CEN/TR 1749:2005 72 Table A.2 – Default values in accordance with BS EN 1443:2003 74 Table B.1 – Resistance factors for use in calculating equivalent heights (Use specific factors from flue or chimney manufacturer’s instructions where possible) 81 Table B.2 – Inlet and outlet resistances 82 Table B.3 – Minimum equivalent heights needed 82 Table C.1 – Minimum dimensions of open flue chimney outlet positions (refer to Figure C.8) 92 Table C.2 – Minimum dimensions of room-sealed chimney outlet positions (refer to Figure C.8) 93 |
| 7 | Foreword a) To acknowledge that European work on chimney standards has brought about the need to redefine chimney concepts and adopt comm… b) To recognize and refer to recent changes in building legislation. c) To cover recent developments in appliance design, flue material and practical experience in the disposal of products of combustion by means of flues. d) To improve advice on flueing and ventilation installation practices and reduce occurrences of CO related incidents attributable to flueing and ventilation for gas appliances. |
| 8 | a) The gas safety regulations for the appropriate legislative region: b) The building regulations for the appropriate legislative region: c) Gas Appliance (Safety) Regulations 1995 [7]. d) Gas Safety (Application) (Isle of Man) Order 1996 [8]. |
| 9 | 1 Scope |
| 10 | 2 Normative references |
| 12 | 3 Terms and definitions 3.1 air supply duct 3.2 appliance compartment 3.3 balanced compartment 3.4 balanced flue appliance 3.5 bathroom 3.6 boundary 3.7 branched chimney 3.8 builder’s opening 3.9 chimney 3.10 chimney plate |
| 13 | 3.11 closed flue 3.12 common flue system 3.13 condensate discharge pipe 3.14 condensate drain 3.15 condensate-free length 3.16 condensing appliance 3.17 connecting flue pipe 3.18 custom-built chimney 3.19 decorative fuel effect gas appliance 3.20 draught break 3.21 draught diverter |
| 14 | 3.22 effective height 3.23 equivalent height 3.24 fan diluted chimney 3.25 fanned draught chimney 3.26 fireplace recess 3.27 flat roof 3.28 flue 3.29 flue break 3.30 flue duct 3.31 flue liner 3.32 flueless appliance (Type A) |
| 15 | 3.33 Installation instructions 3.34 leisure accommodation vehicle 3.35 main flue 3.36 natural draught chimney 3.37 open flue chimney 3.38 open-flued appliance 3.39 passive stack ventilation 3.40 plume management kit 3.41 pluming |
| 16 | 3.42 residential park home 3.43 room-sealed appliance 3.44 room-sealed chimney configuration 3.45 secondary flue 3.46 SE-duct 3.47 shared chimney 3.48 shower room 3.49 subsidiary flue 3.50 system chimney 3.51 terminal 3.52 terminal guard |
| 17 | 3.53 U-duct 4 Competence 5 General 5.1 Compatibility of appliances and chimneys |
| 18 | a) Constraints imposed on potential chimney outlet locations by the following: b) The availability of existing chimneys for re-uses. c) The function of the room in which the appliance is to be installed, particularly in the case of bathrooms, bedrooms and bed-sitting rooms where special rules apply under the Gas (Safety, Installation and Use) Regulations 1998 [1]. d) The need for provision of an adequate air supply for combustion and (where necessary) cooling. e) The extent to which mechanical ventilation is present in the intended location and the effect that this might have on non-room-sealed appliances. f) In the case of fan assisted chimneys, if additional safeguards are required to ensure that the appliance is shut down on failure of the fan. (See Clause 7 for further information.) |
| 19 | a) the appliance manufacturer’s installation instructions (see 5.1.3) or, if these do not specify the chimney to be used, the default values given in Table A.2; and b) the additional requirements for flueing specified in the following standards, as applicable: 1) BS 5546 for water heaters; 2) BS 5871-1 and BS 5871-2 for gas fires; 3) BS 5871-3 for decorative fuel effect gas fires; 4) BS 6798 for boilers; 5) BS 5864 for ducted warm air heaters; 6) BS 6230 for direct and indirect fired warm air heaters; 7) BS 6896 for overhead radiant tubes and radiant plaques. |
| 20 | 5.2 Chimney outlets 5.2.1 General 5.2.2 Location of chimney outlets in relation to basement areas, light wells and retaining walls a) Chimney outlets from room-sealed appliances and fanned draught non-room-sealed appliances may be sited in such areas provided that they are sited not more than 1 m below the top level of the basement area, light well or retaining wall. b) Chimney outlets from room-sealed appliances and fanned draught non-room-sealed appliances may be sited in a basement area or … |
| 21 | 5.2.3 Terminal guards COMMENTARY ON 5.2.3 Attention is drawn to the Building Regulations [3], [4], [5], [6] and supporting documentation [12], [13]. 5.3 Chimneys for use with condensing appliances (open-flued and room-sealed) 5.3.1 General COMMENTARY ON 5.3.1 Condensing appliances are normally of the fanned room-sealed type, although other types are not necessarily excluded. The manufacturer might specify the flue route, siting and terminal. 5.3.2 Chimney materials 5.3.3 Condensate disposal |
| 22 | 5.3.4 Siting of the flue duct outlet 5.3.4.1 General 5.3.4.2 Proximity to a boundary 5.4 Location of appliances 5.4.1 General |
| 23 | 5.4.2 Garages and other hazardous areas 5.5 Passive stack ventilation COMMENTARY ON 5.5 In order to avoid the outlets for a passive stack ventilation system and a chimney being positioned in differe… 5.6 Exchange of information and planning |
| 24 | 5.7 Maintenance |
| 25 | 6 Individual open-flued natural draught Types B11, B12, B13 appliances 6.1 Design 6.1.1 General COMMENTARY ON 6.1.1 Attention is drawn to the Building Regulations [3], [4], [5], [6], supporting documentation [12], [13] and a… 6.1.2 Selection of chimneys COMMENTARY ON 6.1.2 Attention is drawn to the Building Regulations [3], [4], [5], [6] and supporting documentation [12], [13] fo… a) of brick or other masonry construction and lined with one of the following: 2) concrete flue liners conforming to BS EN 1857. b) constructed of flue blocks (see Annex D) conforming to: 2) BS EN 1858 (concrete). c) factory-made insulated metal chimneys conforming to BS EN 1856-1. Single walled metal chimneys shall not be used externally e… 6.1.3 Connecting flue pipes and flue boxes |
| 26 | Figure 1 Typical methods of using a flue liner in a masonry chimney installation serving a gas appliance, other than a back boiler |
| 27 | Figure 2 Installation of a gas fire and combined back boiler using a back boiler enclosure and prefabricated chimney: enclosure arrangement using a false chimney breast and closure panel |
| 28 | Figure 3 Installation of a gas fire and combined back boiler using a back boiler enclosure and prefabricated chimney: enclosure arrangement using a proprietary back boiler box |
| 29 | 6.1.4 Routing and sizing a) drying cabinets; b) appliances having a flue duct outlet area greater than 13 000 mm2; c) gas fires and combined appliances incorporating a gas fire unless a special starter block/adapter has been designed for the p… a) chimneys, constructed in buildings other than single storey, and/or where calculations using Annex B indicate likely clearance of combustion products and subsequent commissioning tests prove satisfactory; or b) gas heating stoves where the appliance manufacturer’s instructions specify that a section of the flue is horizontal; or c) modular boilers incorporated into a fully integrated scheme. |
| 30 | 1) for bonding into and forming an integral part of the building structure (in which case they are mainly in new premises); or 2) for adding-on to either a new or existing building. 6.1.5 Chimney outlets 6.1.5.1 General positioning 6.1.5.2 Adjacent structures COMMENTARY ON 6.1.5.2 Where the horizontal distance between the chimney and a structure on a flat roof exceeds 1.5 m and is grea… |
| 31 | 6.1.6 Condensation a) Gas appliances shall not be installed on single wall chimneys which are routed externally, except for the protrusion above a roof line, since this increases the likelihood of condensation occurring, particularly on cold start up of the appliance. b) Gas appliances shall not be installed on metal twin walled chimneys which have only an air gap for insulation and have external lengths in excess of 3 m. c) Where prolonged condensation cannot be avoided, only flue liner and jointing materials classified as suitable for wet applica… a) in the case of a brick chimney, lining the chimney with a flexible chimney liner conforming to BS EN 1856-2 approved for wet applications (W), see 6.1.6c); b) using a chimney having a lower heat loss such as a double wall metal chimney conforming to BS EN 1856-1. |
| 32 | Table 1 Condensate-free lengths of individual open flue used with a gas fire |
| 33 | Figure 4 Maximum lengths for condensate-free chimneys for appliances other than gas fires |
| 34 | 6.1.7 Existing chimneys 6.1.7.1 Suitability and adoption a) The route of the chimney, in order to establish whether there are any changes of direction which might adversely affect the performance of the chimney or result in blockage. b) The existence of other connections. c) The terminal should be examined and replaced as necessary (see 6.1.5). It is particularly important to ensure that the chimney has not been closed over or otherwise modified. d) The condition of the chimney to ensure that it is sound. If unlined, the inner surface is not showing signs of deterioration such as loose mortar or parging. e) Faults to be considered for rectification should include chimney flaunching, damp-proof course at roof level, brick pointing and terminal integrity. |
| 35 | 6.1.7.2 Obstructions, connections, sweeping and sealing a) If the immediately previous use of the chimney has been for a solid fuel appliance, the chimney might have accumulated soot d… b) All existing chimneys, irrespective of the fuel used, might have been constructed without a properly clear flue or, especiall… |
| 36 | 6.1.7.3 Fitting an appliance to an unlined chimney 6.1.7.4 Lining |
| 37 | Table 2 Minimum void dimensions required below appliance connections |
| 38 | Table 3 Appliance/chimney combinations which require the chimney to be lined Figure 5 Boiler connections to existing brick chimney |
| 39 | 6.2 Installation 6.2.1 General 6.2.2 Support |
| 40 | 6.2.3 Jointing and weatherproofing 6.2.3.1 General COMMENTARY ON 6.2.3.1 The method of jointing between chimney components differs according to the product. Some products, such as… 6.2.3.2 Double-wall metal chimney (previously referred as double-wall flue pipe) COMMENTARY ON 6.2.3.2 As a double-wall metal chimney is assembled, each joint should be fully tightened before proceeding to the… |
| 41 | 6.2.3.3 Flue blocks COMMENTARY ON 6.2.3.3 Flue blocks are more resistive to flow than metal chimneys of the same cross-sectional area, and any morta… 6.2.4 Temperature effects |
| 42 | 6.2.5 Protection of metal chimneys COMMENTARY ON 6.2.5 Where a metal chimney is situated within a dwelling, the risk of damage to the chimney or to persons can be … 6.2.6 Terminals 6.3 Commissioning 6.3.1 General |
| 43 | 6.3.2 Methods of test 6.3.2.1 Visual check COMMENTARY ON 6.3.2.1 The loft space should be inspected to ensure that any chimney passing through it is complete, continuous a… a) is unobstructed, complete, and continuous throughout its length; b) serves only one room or appliance; c) has the terminal correctly sited in accordance with 6.1.5 and a weather tight joint between the terminal and the chimney; d) any dampers or restrictor plates have been removed or permanently fixed in the open position to leave the main part of the flue unobstructed; e) any catchment space is the correct size, free of any debris and any gaps into the catchment space are sealed from the surrounding structure. 6.3.2.2 Flue flow test (smoke test) a) Having established that an adequate air supply for combustion has been provided in accordance with the appliance requirements, close all doors and windows in the room in which the appliance is to be installed. b) Carry out a flow visualization check using a smoke pellet that generates at least 5 m3 of smoke in 30 s burn time at the inte… |
| 45 | 6.3.2.3 Checks with appliance connected (spillage test) COMMENTARY ON 6.3.2.3 If spillage is evident in any of these cases (including the situation when no fan is present) the test sho… a) New or used appliances shall not be installed unless the appliance manufacturer’s instructions are available to the installer. Where the appliance manufacturer’s instructions are not available, the appliance manufacturer shall be consulted. b) In the room: c) Close any passive stack ventilation and repeat the test. If spillage is detected, switch off the appliance, disconnect, and rectify the fault. d) Where the installation instructions do not contain specific instructions for checking spillage, proceed as follows. 2) With the appliance in operation carry out a flow visualization check by applying a smoke producing device, e.g. smoke match, … 3) Close any passive stack ventilation and repeat the test. 4) If spillage occurs leave the appliance operating for a further ten minutes and re-check. If spillage still occurs switch off, disconnect the appliance and rectify the fault. e) If there are fans elsewhere in the building the tests shall be repeated with all internal doors open, all windows, external doors and adjustable vents closed and all fans in operation. |
| 46 | 6.4 Radon gas systems present 6.5 Maintenance |
| 47 | 7 Individual open-flued fanned draught Types B14, B22, B23 appliances and fanned draught chimneys 7.1 Design 7.1.1 General – fanned draught chimneys 7.1.2 Terminals |
| 48 | 7.1.3 Extra requirements for fans installed on site in the chimney 7.1.3.1 Fan and chimney 7.1.3.2 Safety control |
| 49 | 7.1.4 Choice of fan, chimney route and size COMMENTARY ON 7.1.4 The appliance manufacturer’s instructions should be consulted for advice on the flue size and maximum length of flue permitted. a) 0.15 mbar if the chimney outlet is located as specified in 6.1.5; b) 0.75 mbar except when the chimney outlet is located as specified in 6.1.5. 7.2 Installation COMMENTARY ON 7.2 The use of a fan can introduce relatively high pressure differences which necessitate additional precautions in the construction of the chimney. 7.3 Commissioning 7.3.1 Fans integral with an appliance 7.3.2 Fans installed on site a) the fan speed shall be set in accordance with the fan manufacturer’s commissioning instructions; b) all safety controls specified by 7.1.3.2 shall be checked for safe operation; c) the safety control shall be checked to ensure that it shuts off the gas supply to the main burner within 6 s of any spillage occurring from the draught diverter or any other flue break in accordance with the appliance manufacturer’s instructions; d) clearance of combustion products from any other open-flued appliance in the room or adjoining room or space shall be checked with the fan-powered chimney in operation and all external doors and windows closed, and with the interconnecting door open. |
| 50 | Table 4 Minimum flow rates for fanned flues 7.4 Maintenance 8 Shared open flue chimney for natural draught Types B11, B12, B13 appliances 8.1 Design 8.1.1 General a) each appliance shall be of the natural draught type and fitted with a draught diverter; b) each appliance shall be fitted with a flame supervision device; |
| 51 | c) each appliance shall incorporate a safety control which is designed to shut down the appliance before there is a build up of a dangerous quantity of the products of combustion in the room concerned; d) the flue shall be sized so as to ensure complete evacuation of the combustion products from the whole installation; e) the chimney shall be installed so that there is access for inspection and maintenance; f) appliances shall be in the same room or space, or on different floors as described in 8.1.3. 8.1.2 Appliances in the same room using a common flue COMMENTARY ON 8.1.2 Further advice, regarding sizing, when two appliances use one flue in the same room, can be obtained from th… 8.1.3 Appliances installed on different floors of a building COMMENTARY ON 8.1.3 In each room or internal space containing an appliance connected to the shared flue, the number of permanent… a) The main chimney shall not be part of an external wall or a metal chimney encased in a duct comprising part of an external wall or situated externally. b) The nominal cross-sectional area of the main flue serving two or more appliances installed in different storeys of a building shall be not less than 40 000 mm2, and shall be sized in accordance with Table 5. c) Each appliance shall discharge into the main flue by way of a subsidiary flue or connecting flue pipe not less than 1.2 m abo… d) For newly built chimneys, all appliances shall be of the same type, being any one of the types specified in Table 5, and the … |
| 52 | e) When connecting new appliances to existing chimneys, replacement appliances shall be of the same type and not greater in inpu… f) Fanned flued appliances of Types B14, B22 and B23 shall not be used. g) All appliances connected to the flue shall be labelled as such to indicate that the flue is shared. Table 5 Appliances discharging by way of subsidiary flue into a main flue |
| 53 | Figure 6 Flue block types and shared chimney |
| 54 | 8.1.4 Terminal design and location 8.2 Installation 8.3 Maintenance 9 Room-sealed natural draught chimney configurations (balanced flue) for Type C11 appliances 9.1 General |
| 55 | 9.2 Installation 9.2.1 Terminal a) the car port or other add-on extension should have at least two open and unobstructed sides; b) the dimension F given in Table C.2, should be taken as the vertical distance between the lowest point of the roof and the top of the terminal; c) if the roof is of plastics material then the installation should be treated with great care as there is no simple method of protecting the roof. |
| 56 | 9.2.2 Jointing and weather sealing COMMENTARY ON 9.2.2. When installing room-sealed appliances in properties of timber framed construction, care should be taken to… 9.2.3 Temperature effects 9.3 Installation checks a) the seal between the combustion circuit and the room is effective; b) the flue duct and air duct are either continuous through the wall or, if of the telescopic variety, that any sealing tape required by the appliance manufacturer’s instructions has been fitted; c) no debris is contained within the assembly; d) the joint between the terminal and the wall is weatherproof; e) internal equipment, e.g. thermocouples, wires, are securely held or positioned to ensure that they do not interfere with the sealing of the combustion circuit, and all grommets, etc., are in place. |
| 57 | 9.4 Maintenance COMMENTARY ON 9.4 Routine maintenance should be carried out on all gas appliances and their chimney configuration, in accordance… a) the fastenings or fittings supplied by the manufacturer for securing the combustion circuit seal shall be undamaged; b) the combustion circuit seal material/gasket shall be in a safe condition for use or it shall be replaced by a seal/gasket specified by the appliance manufacturer; c) the combustion circuit components, e.g. case, etc., shall show no sign of distortion that affect sealing; d) the combustion circuit shall not be corroded to such an extent that the soundness of the case is affected. 10 Room-sealed: fanned draught chimney configurations for balanced flue (Type C12, C13, C32 and C33) and non-balanced flue (Type C52, C53, C62 and C63) appliances 10.1 Design options 10.1.1 10.1.1 General |
| 58 | 10.1.2 Room-sealed: balanced flue appliances (Types C12, C13, C32, C33) 10.1.3 Room-sealed: non-balanced flue appliances (Types C52, C53) COMMENTARY ON 10.1.3 The air inlet and flue terminal can be located on the same or different faces of a building, i.e. in differ… 10.1.4 Room-sealed: terminals supplied separately from appliance (Types C62, C63) COMMENTARY ON 10.1.4 The installer should establish the compatibility of a terminal system with the appliance. The appliance manufacturer’s advice should be sought and followed. 10.2 Installation 10.2.1 Terminals |
| 59 | a) at least 2.0 m from an opening in a building directly opposite; and b) so that the products of combustion are not directed to discharge across a boundary. 1) the car port or other add-on extension should have at least two open and unobstructed sides; 2) the dimension F given in Figure C.8 should be taken as the vertical distance between the lowest point of the roof immediately above the terminal and the top of the terminal; 3) if the roof is of plastics material then the installation should be treated with great care as there is no simple method of protecting the roof. |
| 60 | 10.2.2 Jointing and weatherproofing COMMENTARY ON 10.2.2 When installing room-sealed chimney configurations in properties of timber framed construction, (see the In… 10.2.3 Temperature effects 10.2.4 Enclosed chimneys COMMENTARY ON 10.2.4 Many modern room-sealed fanned draught appliances are designed for long flues which enables builders to sit… |
| 61 | 10.3 Installation checks a) the sealing method used by the appliance manufacturer to provide the room seal between the combustion chamber and the room is intact and in good condition; b) the flue duct or combined chimney configuration are either continuous throughout the wall or, if they are telescopic, then any sealing tape required by the appliance manufacturer’s instructions has been fitted; c) no debris is contained within the room-sealed chimney configuration; d) the joint between the terminal and the wall is weatherproof; e) internal equipment, e.g. thermocouples, wires, are securely held or positioned to ensure that they can not interfere with the sealing of the combustion circuit, and all grommets, etc., are in place. 10.4 Maintenance 10.4.1 General COMMENTARY ON 10.4.1 Routine maintenance should be carried out on all gas appliances and their chimney configurations, in accord… a) the fastenings or fittings supplied by the manufacturer for securing the combustion circuit seal shall be undamaged; b) the combustion circuit seal material/gasket shall either be in a safe condition for use or it shall be replaced by a seal/gasket specified by the appliance manufacturer; c) the combustion circuit components, e.g. case, shall show no sign of distortion that might affect sealing; d) the combustion circuit shall not be corroded so as to affect soundness. |
| 62 | 10.4.2 Room-sealed fan assisted positive pressure gas appliances a) the general integrity of the appliance; b) that any leakage of combustion products from the case seals is minimal. |
| 63 | 11 Balanced compartment 11.1 General COMMENTARY ON 11.1 The balanced compartment is a method of installing an open-flued appliance in a room-sealed situation and arr… Figure 7 Balanced compartment installations |
| 64 | 11.2 Design COMMENTARY ON 11.2.1 Chimney and ventilation arrangements can be designed for individual applications, or proprietary systems ca… COMMENTARY ON 11.2.2 Where a proprietary system such as that referred to in the recommendations on 11.2.1 is used, the system ma… 11.3 Balanced compartment construction COMMENTARY ON 11.3 A room-sealed effect is essential to the safe operation of a balanced compartment. When the appliance is capa… |
| 65 | 11.4 Temperature effects 11.5 Terminals 11.6 Commissioning 11.7 Maintenance |
| 66 | 12 Room-sealed Types C2 and C4 appliances for shared chimneys 12.1 Selection and installation of a suitable chimney 12.1.1 General COMMENTARY ON 12.1.1 The route of a SE-duct or U-duct is an intrinsic part of the design of a building. System chimneys may be i… Table 6 Normal SE-duct block sizes in existing buildings |
| 67 | 12.1.2 SE-ducts COMMENTARY ON 12.1.2 The horizontal ductwork for the air entry to the base of the vertical sections may be below ground floor le… a) a horizontal duct run from one side of the building to another; or b) a single inlet taken from a zone of neutral pressure, e.g. an underground space. 12.1.3 Sizing SE-duct and U-duct chimneys Table 7 SE-duct sizes for continuously burning appliances (e.g. boilers, gas fires) in flats (This table should only be used for non-condensing appliances installed on precast concrete block chimneys) |
| 68 | Table 8 SE-duct sizes for combinations of instantaneous water heaters (30 kW input rating) and continuously burning appliances (… |
| 69 | Figure 8 Shared room-sealed systems |
| 70 | Figure 8 Shared room-sealed systems (continued) |
| 71 | 12.1.4 U-ducts 12.1.5 Shared system chimneys (common balanced flue) a) Concentric negative pressure chimney which can be used on room-sealed fan or non-fan draught condensing or non-condensing C4 appliances. b) Concentric positive pressure chimney which can be used on room-sealed fan draught condensing or non-condensing appliances. Th… c) Separate (twin pipe) negative pressure flue ducts which can be used on room-sealed fan draught condensing or non-condensing appliances. d) Separate (twin pipe) positive pressure flue ducts which can be used on room-sealed fan draught condensing or non-condensing a… 12.1.6 Sizing for shared system chimneys |
| 72 | Table 9 Cross-sectional area for ducts in shared system chimneys used for condensing and non-condensing appliances (one appliance per storey) |
| 73 | Table 10 Cross-sectional area for ducts in shared system chimneys used for condensing and non-condensing appliances (two appliances per storey) 12.2 Terminal design and location 12.2.1 Roof terminals COMMENTARY ON 12.2.1 Specialist advice should be sought at the design stage concerning the chimney terminal. Positioning a terminal away from roof structures is preferable to raising the terminal. 12.2.2 Low level entry duct design |
| 74 | a) Air Inlet Duct Label. “This duct supplies air to the building’s gas appliances and their flueing system in accordance with BS… b) Duct Grille Label. “The duct behind this grille supplies air to the building’s gas appliances and their flueing system in acc… 12.3 Inspection 12.4 Selection and installation of compatible appliances 12.4.1 SE-duct and U-duct installations using Type C2 appliances |
| 75 | 12.4.2 Appliances for shared system chimneys 12.4.2.1 Type C4 for negative pressure shared system chimneys 12.4.2.2 Appliances for positive pressure shared system chimneys 12.4.3 Replacement appliances |
| 76 | 12.5 Commissioning |
| 77 | 12.5.1 New buildings: all new appliances 12.5.2 Existing buildings: single replacement appliances 12.6 Maintenance 12.6.1 Maintenance of the shared flue system COMMENTARY ON 12.6.1. Since inadequate installation or the operation of any one appliance connected to a shared flue system migh… 12.6.2 Maintenance of room-sealed appliances connected to a shared flue system |
| 78 | 13 Special categories of chimney 13.1 Chimneys for Type C7 (“Vertex”) appliances COMMENTARY ON 13.1 An uninhabited ventilated roof space designed and constructed to be ventilated to the standard required by th… 13.2 Other open flue fanned draught chimneys 13.2.1 Shared open flue fanned draught chimneys |
| 79 | 13.2.2 Fan diluted flue systems |
| 80 | Annex A (informative) Classifications A.1 Classification of appliances by method of evacuation of products of combustion Table A.1 Classification of gas appliances used in the UK according to the method of evacuation of products of combustion (types) – from PD CEN/TR 1749:2005 |
| 81 | A.2 Classification according to European chimney format prescribed in BS EN 1443:2003 A.3 Default values to European chimney formats |
| 88 | Annex B (informative) Calculation method for flue sizing |
| 94 | Annex C (normative) Chimney outlet positions C.1 Open flue chimney outlet COMMENTARY ON C.1 Terminal positions at or near the ridge of a pitched roof are often preferable to those on the slope of the ro… a) at least 2 m from an opening in a building directly opposite; and b) so that the products of combustion are not directed to discharge across a boundary; c) for condensing appliances discharging horizontally, at least 2.5 m from a facing wall, fence, building or property boundary. |
| 95 | Figure C.1 Open flue, natural draught chimney outlet locations for pitched roofs |
| 96 | Figure C.2 Open flue, natural draught chimney outlet locations adjacent to structures on pitched roofs Figure C.3 Open flue or room-sealed, natural or fanned draught chimney outlet locations adjacent to windows or openings on pitched roofs |
| 97 | Figure C.4 Open flue, natural draught chimney outlet locations on flat roofs |
| 98 | Figure C.5 Open flue, natural draught chimney outlet locations near adjacent structures or buildings Figure C.6 Room-sealed configuration outlet location on pitched roofs |
| 99 | Figure C.7 Open flue, fanned draught chimney and room-sealed configuration outlet locations adjacent to structures on pitched roofs Figure C.8 Chimney outlet positions (Refer to Table C.1 for open flue chimney outlets and Table C.2 for room-sealed chimney configuration outlets) |
| 100 | Table C.1 Minimum dimensions of open flue chimney outlet positions (refer to Figure C.8) C.2 Room-sealed chimney configuration outlets C.2.1 Horizontal outlets C.2.2 Vertical outlets |
| 101 | Table C.2 Minimum dimensions of room-sealed chimney outlet positions (refer to Figure C.8) |
| 102 | Figure C.9 Example of how a natural draught, room-sealed chimney configuration outlet position is measured |
| 103 | Figure C.10 Example of how a fanned draught room-sealed chimney configuration outlet and a fanned draught open flue chimney outlet position is measured |
| 104 | C.3 Proximity of flue duct outlets to boundaries Figure C.11 Proximity of flue duct outlet to a boundary |
| 105 | Annex D (informative) Guidance on the design and installation of flue block systems in the UK D.1 General a) the gas flue blocks conform to BS EN 1806 (clay) or BS EN 1858 (concrete); b) the flue block system is installed in accordance with the flue manufacturer’s installation instructions; c) any surplus jointing material projecting into or deposited in the flue is removed during installation; d) the additional guidance given in D.2 to D.9 is followed. D.2 Design considerations a) The flue should take the most direct practicable route from the appliance to the outlet. Where practical an essentially vertical route from the appliance to the outlet is desirable with the minimum of inclined runs of flue (see 6.1.4). b) The layout of the flue should be designed to avoid affecting or cutting into supporting joists, beams, roof timbers and any other load bearing elements of the building. c) A minimum of 600 mm of vertical flue directly above the appliance connection or the recess created by the starter and cover gas flue blocks should be provided. d) The gas flue block system should have an equivalent height at least equal to that required for the appliance to be connected to the flue system, as recommended in this British Standard. e) When a gas flue block system is to be connected to a terminal using a flue pipe system the recommendations given in D.8 should be followed. f) When using bonded gas flue blocks, the design and installation should take into account the height of the starter block and the height of the lintel block, to ensure that the gas flue blocks above align with and bond into the masonry courses. |
| 106 | g) The layout of the complete flue from the outlet of the appliance to the outlets should be designed to meet the flue requireme… h) Flue block systems should only be used where the gas appliance manufacturer’s instructions state that it is permitted. The co… |
| 107 | Figure D.1 Gas flue blocks |
| 108 | Figure D.2 Typical flue block systems (general arrangement) |
| 109 | Figure D.3 Bonded gas flue block system for timber frame construction |
| 110 | Figure D.4 Typical construction details for gas flue block systems in internal walls Figure D.5 Typical construction details for gas flue block systems in external walls |
| 111 | D.3 Temperature effects a) Due to possible high surface temperature on the wall directly above an appliance the gas flue blocks should not be directly f… b) When a facing is placed in front of the gas flue blocks it is essential that any gaps created between the gas flue blocks and facing around the recess opening is permanently sealed. c) It is considered good practice to provide a minimum clearance of 50 mm between the inner face of the gas flue blocks and any … d) Fixing devices should not penetrate any of the gas flue blocks. e) Where a flue block system is constructed as part of an external wall, the cavity at that location should be insulated with ap… D.4 Outlets a) When a gas flue block system is to be connected to a terminal using a flue pipe system the recommendations given in D.8 should be followed. b) If a masonry chimney stack is required to be above the roof line, the gas flue blocks should be continued up to the outlets a… c) The gap between the liners and surrounding masonry cladding may be left as a small air space or preferably filled with a ligh… |
| 112 | d) The free-standing height of the masonry chimney stack should be structurally stable. It is good practice for the maximum free… D.5 Installation of the gas flue blocks a) Each gas flue block should be examined before installation. Any gas flue blocks which are broken or cracked should not be use… b) Bonded gas flue blocks should be built in, course by course, with the surrounding masonry as the work proceeds and bonding sh… c) Non-bonded gas flue blocks or blocks designed to be built free-standing or against a wall should be properly supported or tied into adjacent walls in accordance with the flue manufacturer’s installation instructions. d) Inclined sections of flue should only be made using the appropriate offset gas flue blocks. e) The gas flue blocks should be laid and jointed in accordance with the flue manufacturer’s installation instructions, which might specify assembly with the spigot or socket of the block being uppermost. f) Joints between gas flue blocks should be fully bedded and sealed with jointing material to produce a continuous flue. Any joi… D.6 Jointing material a) Jointing material, such as ready mix fire cement, refractory hydraulically setting mortar or standard mortar as used for cons… |
| 113 | b) Whatever jointing material is used it should be proven as being able to withstand the temperatures and products of combustion created during the operation of the heating appliance. c) As some of these jointing materials can take many hours to harden, the flue construction should be protected against exposure… D.7 Gas flue block installations projecting into cavity wall construction D.8 Flue pipe system installation in roof space connecting to the outlets a) When a gas flue block system is to be connected to an outlet above the roof or at the roof ridge using a flue pipe system, th… b) A transfer block should be used to facilitate the connection to the flue pipe system and be located to ensure that the flue pipe system can take the most practicable vertical route to the outlets without an excessive inclined run. c) The flue pipe system should be installed and supported in accordance with the flue pipe manufacturer’s installation instructi… d) The flue pipe system should generally be installed at an angle not more than 45˚ from the vertical (see 6.1.4). e) If adjustable bends are used care should be taken to ensure that they are not strained such as to cause damage or structural breakdown of the internal wall of the flue. f) Flue pipe system components should not be cut unless specifically permitted in the manufacturer’s installation instructions. g) All joints should be checked to ensure that they are securely made and any components that are damaged, particularly at the joints or in the flue are not used. |
| 114 | D.9 Checking the gas flue blocks during and after installation a) Ensure that all the gas flue blocks, including any starter and lintel blocks are in good condition and installed correctly. b) Check that all joints have been correctly made to achieve a completely sealed joint. c) Visually inspect the flue and remove any excess jointing material or mortar that has extruded or dropped into the flue. d) To ensure that all joints have been correctly made it is recommended that the flue flow smoke test specified in 5.3.2.2 is ca… a) That the gas flue blocks, and if used the flue pipe system, have been installed correctly to the required layout to create a continuous flue to the outlet. b) That all joints have been properly sealed. c) That the flue throughout its length is clear of any jointing material, mortar or debris. d) That any flue pipe system, if used, is correctly installed and supported. e) That the correct terminal is securely fitted in the correct position. |
| 115 | Annex E (informative) Checking of case seals and the general integrity of room-sealed fan assisted positive pressure gas appliances |
| 116 | Figure E.1 Checklist for checking of case seals and the general integrity of room-sealed fan assisted positive pressure gas appliances |
| 117 | Annex F (normative) Design criteria for terminals for shared system chimneys Figure F.1 Permitted recirculation of combustion products |
| 118 | Bibliography |
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| 120 | [12] GREAT BRITAIN, The Building Regulations Approved Document F, Ventilation, 2006. London: The Stationery Office. [13] GREAT BRITAIN, The Building Regulations Approved Document J, Heat Producing Appliances, 2002. London: The Stationery Office. [14] BRITISH GAS plc: IM/28: Appliances in commercial garages (1st edition) (available from Institution of Gas Engineers, Loughborough), 1993. [15] CORGI. Gas industry unsafe situations procedure. Hampshire: CORGI, 2005 . [16] DEPARTMENT OF FINANCE AND PERSONNEL. Technical Booklet L: Combustion appliances and fuel storage systems. London: HMSO, 2006. [17] SCOTTISH BUILDING STANDARDS AGENCY. Domestic Handbook. London: TSO, 2007. [18] GREAT BRITAIN. The Asbestos (Prohibitions) Regulations 1992, SI 1992, No. 3067, as amended. London: HMSO. [19] HETAS. The official guide to approved solid fuel products and services. Gloucestershire: HETAS. [20] BRE. Buildings and radon. Hertfordshire: BRE Bookshop, 1999. [21] INSTITUTION OF GAS ENGINEERS AND MANAGERS. Installation of gas appliances in industrial and commercial premises, IGE/UP/10. Loughborough: Institution of Gas Engineers and Managers, 2002 . [22] CORGI. TB 200, Room-sealed fanned draught flue systems concealed within voids. Hampshire: CORGI, 2007. [23] ODPM. Guide to the Condensing Boiler Installation Assessment Procedure for Dwellings, (Reference No. 04 BD 03021). ODPM (now CLG), April 2005. ISBN 1851127844. |
