Ventilation
The ventilation to provide the stove with air has to be regarded as an integral part of the
flue system, because unless the air passing through the flue is replaced with equal
amounts of air entering the house, the flue will cease to function. The cooler the outside
temperature and the harder the stove is working to maintain the required temperature
inside, the cooler the incoming air and the greater its flow. Strategically positioned,
correctly sized and baffled vents will avoid any discomfort from draughts in the room. If
the vent is directly behind the stove then an internal baffle is recommended.
Any room or space containing an appliance should have a permanent ventilation
opening of free area at least 550mm sq. for each kW of rated. In older dwellings, pre-
2008, with an air permeability which is greater than 5.0
m
3
/hr /m
2
the first 5Kw may be
ignored.
The Flue and Connections
Bends in flue pipe
Top exit
A flue shall have no more than four bends, each providing a maximum change of direction of 45°, there should be not
more than two of these bends before an access point for sweeping and two between a sweeping point and the flue
terminal.
On top exit stoves, ideally, the flue should rise vertically 1 meter before the first bend. It is however permissible to
have a bend no greater than 45° from the top flue outlet, or off the top of a
“
T
”
pipe, as long as it does not adversely
affect the flue draught.
Back exit
For a rear-outlet application using a T pipe, this should be treated as t
wo 45º bends. If a “T”
piece is to be used, the
horizontal flue run from the back outlet of the stove shall only be used to connect the stove to a
“
T
”
pipe and shall not
be more than 150mm in length.
If, due to the location of the stove, the horizontal run is marginally greater than 150mm then it permissible as long as
it is not detrimental to the flue draught requirements of the appliance. It must be noted that the flue draught will take
longer to establish the greater the horizontal length of flue and the sooting up of the glass on lighting will be greater.
