Every rule your project must meet, found for you.
Search Northern Ireland’s planning and building-control guidance, ask a question in plain English, or generate a project compliance checklist — every answer cited to the source.
Working to a specific project? Generate a compliance checklist →
Answers, with citations
Ask in plain English and get an answer that links to the exact source clause — never an unsourced guess.
Scoped to your council
Overlay a council's local development plan on the Northern Ireland-wide regulations and policy.
Project compliance checklist
Characterise a project and get the requirements that apply, grouped by work area. Try it →
The library
Search the source guidance
40 results · filtered
Natural draught flue
NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Natural draught flue – the combustion products flow into the flue as a result of the buoyancy force produced due to the difference between the temperature of the gases within the flue and the temperat
combustion-appliancesflue-systemsOpen-flued appliance definition
NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Open-flued appliance – one which draws its combustion air from the room or space within which it is installed and which requires a flue to discharge its products of combustion to the outside air. See
combustion-appliancesflue-systemsFilling spaces between chimney liner and masonry
2.22NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Spaces between the lining and the surrounding masonry should not be filled with ordinary mortar. In the absence of the liner manufacturer's instructions, the space should be filled with one of the fol
combustion-appliancesflue-systemschimneyConstruction of flue block chimneys
2.23NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
A flue block chimney should be constructed of factory-made components suitable for the intended application and installed in accordance with the manufacturer's instructions. The flue blocks should hav
combustion-appliancesflue-systemschimneySealing joints and forming bends in flue block chimneys
2.24NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Joints should be sealed in accordance with the flue block manufacturer's instructions. Bends and offsets should only be formed with matching factory-made components.
combustion-appliancesflue-systemschimneyWall thickness for masonry and flue block chimneys
2.25NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
The thickness of the walls for a masonry chimney around the flue, excluding the thickness of any flue liner, should be in accordance with Diagram 2.4.
combustion-appliancesflue-systemschimneystructuralFlue pipe materials
2.26NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
A flue pipe should be constructed from – (a) cast iron complying with BS 41; (b) metal flue pipes appropriately designated in accordance with BS EN 1856: 2 to suit the appliance and types of fuels to
combustion-appliancesflue-systemsFlue pipe joint installation
2.27NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
A flue pipe with spigot and socket joints should be fitted with the socket facing upwards to contain moisture and other condensates in the flue. Joints should be made gas-tight by the use of proprieta
combustion-appliancesflue-systemsPlastic flue pipe designation
2.28NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
A plastic flue pipe should be appropriately designated in accordance with BS EN 14471 to suit the appliance, fuel and flue characteristics.
combustion-appliancesflue-systemsExisting flue re-use and repair
2.29NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Where it is proposed to bring an existing flue back into use, or an existing flue is to be used with a different type or rating of combustion appliance, it should be cleaned, visually inspected and if
combustion-appliancesflue-systemsDefective flue lining
2.30NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
A defective flue should be lined using the materials and components described in Sections 3, 4, and 5 dependent upon the type of combustion appliance proposed.
combustion-appliancesflue-systemsFlue area sizing for lining
2.31NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
The use of an oversized flue can be unsafe so a flue should be lined to reduce the flue area to suit the intended combustion appliance.
combustion-appliancesflue-systemsMetal liner replacement on appliance replacement
2.32NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
If a chimney has been relined in the past using a metal lining system and the appliance is being replaced, the metal liner should also be replaced, unless it can be proven that it was recently install
combustion-appliancesflue-systemsFlexible metal flue liners for chimney relining
2.33NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
A chimney may be relined using a flexible metal flue liner, appropriately designated in accordance with BS EN 1856: 2 to suit the appliance, fuel and flue gas characteristics. Flexible flue liners sho
combustion-appliancesflue-systemsOpenings for inspection and cleaning
2.43NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Openings for inspection and cleaning should be formed using purpose factory-made components that are compatible with the flue system. The access cover to the opening should have the same level of gas-
combustion-appliancesflue-systemsFlue cleaning requirements
2.44NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Openings for cleaning the flue should allow easy passage of the sweeping brush and be non-combustible except where fitted to a combustible flue pipe, such as a plastic flue pipe. It should be possible
combustion-appliancesflue-systemsmaintenanceFlue completion checks
2.46NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
A flue should be checked at completion to ensure that it is free from obstructions, satisfactorily gas-tight and constructed with materials and components of sizes that suit the intended application.
combustion-appliancesflue-systemstestingfire-safetyNotice plates for hearths and flues
2.47NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
To satisfy the requirements of Regulation 74 in Part L, a durable notice should be provided to convey – (a) the location of the hearth, fireplace (or flue box) or the location of the beginning of the
combustion-appliancesflue-systemsinformation-provisionPositioning of notice plates
2.48NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Notice plates should be robust, indelibly marked and securely fixed in an unobtrusive but obvious position within the building such as – (a) next to the electricity consumer unit; or (b) next to the c
combustion-appliancesflue-systemsinformation-provisionEuropean Standard flue product designations on notice plates
2.49NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
For flue products whose performance characteristics have been assessed in accordance with a European Standard (EN) and which are supplied or marked with a designation as defined in Section 2, the inst
combustion-appliancesflue-systemsLocation and shielding of flue pipes - basic requirements
3.14NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
A flue pipe should only be used to connect an appliance to its flue. It should not pass through any roof space, partition, internal wall or floor, except to pass directly into a flue through either a
combustion-appliancesflue-systemsfire-safetyProtection of combustible materials from flue pipes
3.15NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
A flue pipe should be located so that it cannot ignite any combustible material. To ensure this – (a) follow the guidance in paragraph 2.37 where the connecting flue pipe is a factory-made metal chimn
combustion-appliancesflue-systemsfire-safetyDiagram 3.3 - Shield configuration for combustible material protection
Diagram 3.3NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
shields should either: a) extend beyond the flue pipe by at least 1.5 x D; or b) make any path between flue pipes and combustible material at least 3 x D long air space of at least 12 mm between non-c
combustion-appliancesflue-systemsfire-safetysolid-fuelProvision of flues for gas appliances
4.22NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
The flue and flue pipe for a gas appliance should – (a) be designed and constructed following the provisions on the selection of components and the manner of their installation as given in paragraphs
non-domesticcombustion-appliancesgas-appliancesflue-systemsLocation of flue outlets near roof windows or openings
Diagram 4.4NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Location of outlets near roof windows or openings (from flues serving gas appliances). The flue should not penetrate the shaded area. Minimum clearance: 600 mm horizontally, 600 mm vertically from roo
non-domesticcombustion-appliancesgas-appliancesflue-systemsroof-penetrationFlue pipe components
4.23NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
The components for a flue pipe should be – (a) any of the options in paragraph 2.26; (b) a sheet metal pipe as described in BS EN 1856: 2; (c) a fibre cement pipe as described in BS EN 1857; or (d) an
combustion-appliancesflue-systemsFlue block chimneys - materials and construction
4.24NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
A flue block chimney should be constructed from either – (a) a factory-made flue block system primarily designed for solid fuel, as described in paragraphs 2.23 and 2.24; or (b) a factory-made flue bl
combustion-applianceschimneysflue-systemsFlue block chimney installation and support
4.25NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
A flue block chimney should be installed with sealed joints in accordance with the flue block manufacturer's installation instructions. Where bends or offsets are required, these should be formed usin
combustion-applianceschimneysflue-systemsMinimum performance designations for chimney and flue pipe components for gas appliances
Table 4.4NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Minimum performance designations for chimney and flue pipe components for use with new gas appliances Appliance type | Minimum designation Boiler: open-flue Natural draught | T250 N2 D 1 O Boiler: op
combustion-appliancesgas-appliancesflue-systemsLining requirements for flues in chimneys with high temperature flue gas (>250°C)
5.21NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Where the flue gas temperature is expected to be greater than 250ºC the liner should be – (a) as per the provisions in paragraph 2.22; (b) as per the provisions in paragraph 3.20; or (c) a flexible st
combustion-appliancesflue-systemsLining requirements for flues in chimneys with lower temperature flue gas (≤250°C)
5.22NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Where the flue gas is expected not to be greater than 250ºC the liner should be – (a) any of the linings described in 5.21 above; or (b) if the appliance is new and of known type, flue lining systems
combustion-appliancesflue-systemsInstallation requirements for flexible metal flue liners
5.23NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
A flexible metal flue liner should be installed in one complete length without joints within the chimney. Other than for sealing at the top and the bottom, the space between the chimney and the liner
combustion-appliancesflue-systemsProtection from hot flue gas temperatures not greater than 250°C
Table 5.3NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Table 5.3 Protecting buildings from hot flue gas temperatures not greater than 250ºC Flue pipe: A flue should be not less than 25 mm from any combustible material, measured from the outer surface of
combustion-appliancesflue-systemsfire-safetyPressure classes
B.8NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Pressure classes are set out in Table B2 and expressed as either 'N', 'P' or 'H' followed by either '1' or '2'. N relates in general to natural draught chimneys i.e. operating under negative pressure
combustion-applianceschimneyflue-systemsCondensate resistance classes
B.9NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Condensate resistance class – expressed as either 'W' for wet or 'D' for dry operations. A product designated 'W', able to contain condensates within the flue, is aimed at condensing appliances. A pro
combustion-applianceschimneyflue-systemsSootfire resistance classes
B.10NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Sootfire resistance class – expressed as either 'G' with sootfire resistance, or 'O' without. A product assigned the designation 'G' has been tested at 1000ºC for 30 minutes.
combustion-applianceschimneyflue-systemsfire-safetyDistance to combustible material
B.11NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
The designation of the minimum distance from the outer surface of the chimney to combustible material is given as xx expressed in millimetres (e.g. the distance 'XX' identified in paragraph 2.37 and D
combustion-applianceschimneyflue-systemsfire-safetyprotection-from-fallingPressure classes table
Table B2NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Table B2 Pressure classes Pressure class | Test pressure Pa | Gas tightness Maximum leakage rate L/s/m2 N1 | 40 | 2.0 N2 | 20 | 3.0 P1 | 200 | 0.006 P2 | 200 | 0.120 H1 | 5000 | 0.006 H2 | 5000 | 0.1
combustion-applianceschimneyflue-systemsCorrosion resistance classes
B.12NI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
Corrosion resistance classes are set out in Table B3 – this is fuel dependant and expressed as 1, 2 or 3. Table B3 Corrosion resistance classes (from BS EN 1443) Corrosion resistance class 1 Possibl
combustion-appliancesfuel-storageflue-systemscorrosion-resistanceReferenced British Standards for Combustion Appliances and Fuel Storage Systems
Appendix ENI-wide·Technical Booklet L Combustion Appliances and Fuel Storage Systems
BS EN ISO 1182: 2002 Reaction to fire tests for building products – Non-combustibility test. BS EN ISO 1716: 2002 Reaction to fire tests for building products – Determination of heat of combustion. BS
combustion-appliancesfuel-storagechimneysflue-systemsfire-safety