6
3.3.
ENCLOSURE VENTILATION
The enclosure must be ventilated. Vents with a minimum total
free area of 14,700mm² must be fitted at the top, and a
minimum total free area of 29,400mm
2
at the bottom.
The purpose of the vents is to allow cooler air to be drawn
into the enclosure through the bottom vent, and warm air out
through the top vent via natural convection back into the
room.
Ensure that adequate ventilation from the lower vents can get
past the open fireplace cabinet.
The upper air vents must not be installed any lower than
200mm from the internal ceiling of the enclosure.
3.4.
FLOOR PROTECTOR (HEARTH)
The dimensions of the floor protector are dependent on the
height above the floor at which the heater is installed.
Base of the firebox is 450mm or more above the floor –
Floor protector must extend a minimum of 300mm in
front of the firebox opening, and 200mm either side of
the opening. It must be constructed from a minimum
5mm thick non-combustible material with a thermal
conductivity not greater than 0.33W/m °K, equivalent to
compressed fibre cement sheet.
Base of firebox less than 450mm above the floor –
Floor protector must extend a minimum 500mm in front
of the firebox opening, and 200mm either side of the
opening. It must be constructed from one of two
options:
a)
Skamotec 225 board – 50mm thick
b)
Ventilated floor protector – two sheets of 15mm
thick compressed fibre-cement sheet with a 1mm
thick sheet of steel between them, spaced off the
floor with 25mm high non-combustible spacers such
as RHS square tubing, or equivalent, with a minimum
ventilation of 2500mm
2
at each end between the
spacers
Non-combustible tiles may be laid over the top of either
floor protector option.
The floor protector can be larger than the minimum
dimensions given here if desired.
Note that if the firebox is less than 250mm above the
floor, the floor beneath the firebox within the enclosure
must be protected with the same material construction
as the floor protector in front of the enclosure.
Vented
casing
NOTE: If using 30mm cement sheet beneath appliance,
this area must be clear of any combustibles beneath
for a minimum of 250mm below. Otherwise, appliance
must be installed on 50mm thick Skamotec 225 or
ventilated hearth – refer to section 3.4)
