Date: 21/7/2022
Version Number: 2022 Issue no.3
Page
9
4.3 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.
Note: If the appliance is fitted with a draught stabilizer (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.
For more detailed guidelines on required ventilation sizes please refer to the Document J Building
Regulations (Combustion Appliances) at the www.planningportal.gov.uk website.
5.Flue And Chimneys
5.1 Requirements
The stove must be connected to a suitable and efficient flue so that products of combustion (fumes)
from the stove are expelled to the outside air. Please remember that chimney draught is dependent
on four main factors:
·
Flue gas temperature
·
Flue height
·
Flue size
·
Flue terminal
To ensure a good updraught it is important that the flue gases are kept warm, and that the flue size
suits the stove. The termination of the outlet at the top of the flue also needs to comply with Building
Regulations. The minimum effective height of the flue must be at least 4.5 meters from the top of the
stove to the top of the flue outlet. When warm the flue draught should be between 0.1 to 0.2mb.
The draw of a chimney / flue can vary in different weather conditions and the customer should be
made aware of this. Failure to correct an over-drawing flue will invalidate the warranty.
