A flue is a duct, pipe or chimney for conveying exhaust gases
from a wood fuel boiler to the outdoors. All wood fuel heating
systems will require a flue.
In some circumstances it may be possible to line an existing
chimney, for example: by inserting a flexible stainless steel flue
liner manufactured specifically for solid fuel use; using a pumped
refractory concrete lining; or adding a clay or concrete liner to
the brickwork.
Where a chimney isn't available, a convenient method of
constructing one is to use prefabricated, insulated, twin wall
chimney components.
Flues must comply with building regulations. The technical handbooks for
domestic and non-domestic properties specify various
requirements for flues for solid fuel appliances.
Most new chimneys and flues will require a building warrant.
Under recent legislation for renewables in domestic properties,
planning permission is not required for wood fuel generation under
45 kW unless:
- the flue exceeds 1m above the roof height (excluding the
chimney) installed on the principal elevation and visible from a
road in buildings in Conservation Areas and World Heritage
Sites.
- the flue is situated within an Air Quality Management
Area.
Publications to download
The Biomass Energy Centre have produced useful guides which
contain information about flues and chimneys: