2.1.2 Corner Installation:
Corner to wall clearance – 275 mm
2.2
Floor Protector (Hearth)
Unless the heater will be standing on a heat resistant floor
such as concrete slab with slate or tiles, it will be necessary to
provide a floor protector (hearth).
The dimensions given in above (Section 2.1) are the minimum
required for the floor protector. It must extend no less than
300 mm in front of the door opening. It may be desirable, for
example aesthetic reasons, for the floor protector to be
larger than these minimum dimensions.
The floor protector shall be constructed of non-combustible
material no less than 15mm thick and with a thermal
conductivity not greater than 0.33W/m
º
K, eg. compressed
cement sheet. The floor protector may be laid directly on the
combustible floor.
For more details and variations on floor protectors refer to
AS/NZS 2918:2001 Clause 2.2, 3.3.1, & 3.3.2.
If it is necessary to install a heater closer to a combustible
surface than the stated requirements in Section 2 of this
Installation Guide, it must be done in accordance with
Australian Standard AS/NZS 2918:2001 Section 3, Tables 3.1
& 3.2.
Shield Construction:- The shield shall be constructed from a
heat resistant material. The shield must be fixed to the
surface that requires protection and NOT the heater.
The Standard allows three options to reduce stated
clearances.
Single layer of continuous material with Minimum Air Gap of
12mm—Clearance Factor = 0.40
Single layer of continuous material with Minimum Air Gap of
25mm—Clearance Factor = 0.30
Two spaced layers of continuous material with Minimum Air
Gaps of 12mm + 12mm—Clearance Factor = 0.20
The shielding must be open at the top and bottom (vented)
to allow a continuous air flow. It is this air flow that keeps
the surface requiring protection cool. Fixings should not
impede this air flow.
The shielding needs to go far enough along and up the wall
so that the original side and rear required clearances are not
compromised. As the flue is now closer to the wall the
shielding should also protect the wall from the flue pipe.
For example:
Side wall clearance for the Big Bakers Oven is 325 mm.
A 12mm gapped shield on the wall with a factor of 0.40.
Calculate:- 325 mm x 0.40 = 130 mm. This is the new side
wall minimum clearance.
The shielding needs to be large enough so that none of the
original clearances of 325 mm are compromised.
3. Reducing Clearances to Combustible Walls
