DEFRA Stove Installation and User Guide
Ideally, adjacent walls should be of suitable non-combustible construction,
preferably brickwork.
In large fireplaces take care that any supporting beam is protected by a 13mm
sheet of heat resistant fire board spaced 12mm off the surface with strips of
non-combustible material. Make sure that there is a gap between an un-insulated
flue system and any combustible material. This gap must be at least 3X the
outside diameter of the flue pipe, or 1.5X the flue diameter to non combustible
surfaces. Please consult the flue manufacturers specification for insulated flues.
2.3
Air for Combustion
All stoves require ventilation to burn safely and correctly. There are a number
of requirements that need to be met when installing a stove, for example, allowing
for the permeability of the house (air permeability is the general seepage of air
into the house via air vents, doors and windows etc.)
There must always be a permanent means of providing air for combustion into
the room in which the stove is installed. Air starvation will result in poor flue draw
and may cause smoke to leak into the room.
For all installations it is recommended that a permanent vent with a total free
area of at least 550mm
2
for every kW above 5kW should be connected directly
to the outside air. Installations in properties built after 2008 should have their
vent increased by a further 330mm
2
for each of the the first 5kW. Alternatively
this air can be supplied through an external wall of an adjacent room, which itself
has to be connected to the room the appliance is installed by a permanent vent
of the same size.
Note: If the appliance is fitted with a draught stabiliser (or if one is fitted to
the flue pipe or chimney in the same room as the appliance) then the permanent
air entry opening (or openings) should be increased by 300mm
2
for each kW of
rated output up to 5kW and an additional 850mm
2
for each kW output over 5kW.
If there is more than one appliance in the property then each appliance
must be supplied with adequate combustion air so that all appliances can be
lit simultaneously.
The positioning of any air vent must be so that it cannot be liable to blockage
or obstruction. Ideally it should also be positioned where it is unlikely to cause a
cold draught. It should not be positioned in the fireplace recess.
BK575 Rev03
3