Twin-wall Metal Flues

• 2 types:
  • With an air gap between the walls
    • external use on longer than 3 meters
  • Fully insulated pipe
• Suitable for all fuels for appliances that operate up to 600°C
• Sleeve must provide minimum 25mm of gap (filled with non combustible material) when passing through combustible material
  • Metal ceiling and metal floor plates used as a seal
• Spigot should face up words

Vitreous Enamelled

• Internal use only
• Socket faces up words
• For making connections from:
  • wood burning stoves
  • cookers and heaters to chimneys
  • flexible liners and flue systems

Flexible Stainless-steel Flue Liner

• Used to line an unsatisfactory existing chimney
• The top and the base of the chimney must be sealed with flaunching and sealing plate respectively
• When chimney exceed a certain length they will require lining:
  • Gas fire (with or without circulator)
    • >10m for external wall
    • >12m for internal wall
  • Gas fire with a back boiler
    • any length
  • Circulator
    • >6m for external wall
    • >1.5m of external length and total length > 9m
  • Other appliances
    • >12m for internal
      • >20m
      • >33m for double wall 125mm metal chimney
    • >10m for external
      • single wall 125mm metal chimney not allowed
      • >28m for double wall 125mm metal chimney
• Class 1 - Wood And Coal Burning (>250°C)
• Class 2 - Gas And Oil Burning (<250°C)
• 225x225mm flue opening

Pre-cast Concrete Blocks

• Must have minimum 3 starter blocks
• Built into the wall during construction
• No excess jointing material left inside flue
• Maximum offset of 30° using a raking block
• Connected to the ridge terminal with a twin-walled insulated pipe

Catchment Space

• Minimum 42litres - volume of the void
• Minimum 15mm - flue spigot protrusion
• Minimum 50mm clearance - between the spigot and the back wall
• Any appliance fitted to an unlined brick chimney or lined brick (flue block/metal) chimney (used for solid fuel or oil):
  • Minimum depth - 250mm
  • Minimum volume - 12 litres
• Any appliance fitted to a lined brick or flue block/metal chimney new or unused, or previously used with gas
  • Minimum depth - 75mm
  • Minimum volume - 2 litres

Flue Gas Collector Box

Flue Height Calculation

Fire Stop Plate