3
Installing Beneath the Floor
•
There must be a minimum clearance of 200mm between any part of the appliance and the lowest part of the
floor structure. In addition to this, refer to section "
Service Clearances
”.
•
The heater must be located within 2m of the access opening, or there is to be a minimum clearance of 1.2m
between the lowest part of the floor structure and ground level, maintained from the access opening to the
heater.
•
All under floor installations must be on a level concrete base (50mm thick), and provision made to drain any
seepage or ground water away from the heater.
•
Permanent artificial lighting must be provided at the heater, with the switch located at the access opening.
•
Lateral (horizontal) flues may be installed in accordance with AS 5601, making sure that the lateral flue section
has a minimum rise of a 20mm per metre of lateral run.
•
The flue must be terminated outside the building in accordance with AS 5601.
1.10 Installation of Internal Heaters in a room, enclosure, residential
garage or plant room
Installation of a gas appliance in a room or enclosure for properties approved for
construction prior to 1
st
of March 2014
1.
Determine if the unit(s) MJ/hr rating for each cubic meter of the room or enclosure, is greater than 3
MJ/hr per m³
e.g.
Unit rating (Ur) = 120 MJ/hr
Room volume (Rv) = 1m x 1m x 2.4m = 2.4m³
Ur/Rv = 120/2.4 = 50 MJ/hr per m³ > 3 MJ/hr per m³
Additional ventilation is required in the room or enclosure
2.
Two permanent openings are required, each equivalent in area to the determined value “A”. The lower
vent shall be located close to the floor or at burner level. The upper vent shall be located at or above
the top of the unit. The two openings may be combined as long as the above conditions are met.
Determine free ventilation area using A = T x F.
Where
A = The minimum free ventilation area, mm²
T = The total gas consumption of all gas appliances, MJ/hr, i.e. 1 x 2PWN20 =92MJ/hr
F = The factor detailed in the below table
Gas appliance location
Source of Ventilation
Factor F
Gas appliance in a room
or enclosure
Directly to outside
Via an adjacent room
300
600
Gas appliance in a plant
room
Directly to outside
Via an adjacent room
150
300
Installation of a gas appliance in a room, enclosure, residential garage or plant room for
properties approved for construction after 1
st
of March 2014
1.
Determine if the unit(s) MJ/hr rating for each cubic meter of the room, enclosure, residential garage or
plant room is greater than 0.4 MJ/hr per m³
e.g.
Unit rating (Ur) = 120 MJ/hr
Room volume (Rv) = 1m x 1m x 2.4m = 2.4m³
Ur/Rv = 120/2.4 = 50 MJ/hr per m³ > 0.4 MJ/hr per m³
Additional ventilation is required in the room, enclosure, residential garage or plant room.
Refer to AS5601 for natural ventilation requirements
Note:
For all other applications, e.g. Mechanical Ventilation, refer to AS5601.
Note:
Directly to outside is either through an outside wall, into a cavity vented to outside, into an
underfloor space or roof space vented to outside.
