NCC 2016 Volume Two
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Part 3.7.3 Heating Appliances
Appropriate Performance Requirements
Appropriate Performance Requirements
Where an alternative heating appliance is proposed as a Performance Solution to that described in Part 3.7.3, that proposal must comply with—
- P2.3.3; and
- the relevant Performance Requirements determined in accordance with 1.0.7.
Acceptable construction manuals
3.7.3.0
P2.3.3 is satisfied for a heating appliance if it is installed in accordance with one of the following:
(a)
* * * * *
(b)
Domestic solid-fuel burning appliances: AS/NZS 2918.
Acceptable construction practice
3.7.3.1 Application
Compliance with this acceptable construction practice satisfies Performance RequirementP2.3.3 for heating appliances.
3.7.3.2 Open fireplace construction
An open fireplace must be constructed as follows (also see Figure 3.7.3.1):
(a)
All masonry must be constructed in accordance with Part 3.3.
(b)
The front hearth must be constructed of stone, concrete, masonry or similar material so that—
(i)
it extends not less than 300 mm beyond the front of the fireplace opening and not less than 150 mm beyond each side of that opening; and
(ii)
its upper surface does not slope away from the back hearth.
(c)
The base of the back hearth must be constructed of stone, concrete, masonry or similar material and any combustible flooring or framing members must be situated not less than 150 mm from its upper surface.
(d)
The fireplace rear and side walls up to a height of 300 mm above the underside of the arch or lintel—
(i)
must be constructed in 2 separate leaves of solid masonry with an overall thickness not less than 180 mm thick, excluding any cavity; and
(ii)
must not consist of concrete block masonry in the construction of the inner leaf; and
(iii)
must be constructed of masonry units with a net volume, excluding cored and similar holes, not less than 75% of their gross volume, measured on the overall rectangular shape of the units, and with an actual thickness of not less than 100 mm.
(e)
The fireplace must be constructed on footings complying with 3.2.5.5.
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Figure 3.7.3.1 FIRE PLACE CLEARANCE FROM COMBUSTIBLE MATERIALS |
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3.7.3.3 Chimney construction
The construction of a chimney must comply with Part 3.3 and the following:
(a)
The walls of the chimney above the level referred to in 3.7.3.2(d) must be lined internally to a thickness of not less than 10 mm with composition mortar parging.
(b)
The chimney or flue must terminate not less than 300 mm above the highest part of the building within a horizontal distance of 3.6 m of the chimney or flue (see Figure 3.7.3.2).
Explanatory information
Explanatory information:
The requirements of this Part are to be read in conjunction with the building sealing requirements in Part 3.12.3. However, it should be noted that Part 3.12.3 does not apply in all States and Territories.
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Figure 3.7.3.2 SECTION SHOWING HEIGHT AND POSITION OF CHIMNEY |
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3.7.3.4 Installation of insert fireplaces and flues
An insert fireplace and flue must comply with the following:
(a)
The insert fireplace must be tested and passed the tests required by AS/NZS 2918.
(b)
The insert fireplace must be fitted into a masonry fireplace (including chimney) constructed in accordance with Part 3.3.
(c)
The flue must be double skin and have been tested and pass the tests required by AS/NZS 2918.
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Figure 3.7.3.3 TYPICAL INSTALLATION OF FIRE PLACE FLUE INSERTS |
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(d)
There must be a clearance of 50 mm between the outer flue and adjacent materials.
(e)
The flue must terminate in accordance with Figure 3.7.3.2.
(f)
The hearth must be constructed in accordance with 3.7.3.2(b), (c) and (e).
3.7.3.5 Installation of free standing heating appliances
The installation of a free standing heating appliance must comply with the following:
(a)
The appliance must—
(i)
be installed with safety clearances determined by testing in accordance with AS/NZS 2918; or
(ii)
be located not less than 1.2 m from adjoining walls (other than a masonry wall); or
(iii)
have a heat shield between the adjoining wall (other than a masonry wall) and the heating appliance in accordance with Figure 3.7.3.4.
(b)
Where a heat shield is used, it must be installed in accordance with Figure 3.7.3.4 and it must be not less than 90 mm thick masonry constructed in accordance with Part 3.3.
(c)
The heating appliance must be installed on a hearth—
(i)
complying with 3.7.3.2(b) and (c), except that the hearth must extend 400 mm from the appliance in accordance with Figure 3.7.3.4; or
(ii)
where a heat shield is installed, in accordance with Figure 3.7.3.4.
(d)
The flue must—
(i)
have been tested and passed the tests required by AS/NZS 2918; and
(ii)
be installed in accordance with Figure 3.7.3.5; and
(iii)
terminate in accordance with Figure 3.7.3.2.
(e)
Flue types or installation of flues in areas not specifically covered by Figures 3.7.3.4 and 3.7.3.5 must be installed in accordance with AS/NZS 2918.
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Figure 3.7.3.4 ACCEPTABLE LOCATION OF FREE STANDING HEATING APPLIANCES |
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| Diagram a. | ELEVATION |
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| Diagram b. | PLAN VIEW |
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Figure 3.7.3.5 ACCEPTABLE FLUE INSTALLATION DETAILS |
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| Note: Flue pipe size — 150 mm maximum (for other sizes see AS/NZS 2918). |
3.7.3.6 Installation of boilers and pressure vessels
The installation of a boiler or pressure vessel heating appliance within a building, must comply with the following:
(a)
The distance between the vent of any explosion relief device and any adjacent wall, roof, ceiling or other solid construction must be calculated in accordance with Table 3.7.3.1.
Table 3.7.3.1 MINIMUM CLEARANCES FOR EXPLOSION RELIEF
| Clearance from | Minimum Clearance (metres) |
|---|---|
| Adjacent wall or ceiling/roof | 0.4(V/3)1/3 or 0.4 m, whichever is the greater |
| Two walls at right angles; or one wall and a ceiling/roof | 0.6(V/3)1/3 or 0.6 m, whichever is the greater |
| Note: V is the internal volume of the boiler or pressure vessel being vented up to the connection of the flue. | |
(b)
Floor surfaces beneath a boiler or pressure vessel must be water resistant and formed to drain away from supports and structural building elements.
(c)
Where a safe tray is provided to trap liquids, it must be manufactured from a material resistant to corrosion from the contents of the boiler or pressure vessel.
(d)
Building elements surrounding a boiler must be protected from any furnace heat by refractory material or effective air spaces so that—
(i)
steel elements do not exceed a temperature of more than 300°C; and
(ii)
concrete elements do not exceed a temperature of more than 200°C; and
(iii)
timber elements do not exceed a temperature of more than 150°C.
Explanatory information
Explanatory information:
The requirements of 3.7.3.6 are limited to a boiler or pressure vessel heating appliance within a building. Therefore the provision does not apply to a boiler or pressure vessel outside of these limitations, such as a portable gas appliance.
provides the minimum clearance required which is based on the volume of the space being vented. The minimum clearance is determined by a formula which includes the volume of the space being vented.
The intention of the explosion relief provisions is that, in the event of an explosion, the extent of damage is limited.
The minimum clearance determined in the first row is 0.4 m from an adjacent wall or ceiling/roof.
The minimum clearance determined in the second row is 0.6 m from two walls at right angles, or one wall and a ceiling/roof. This scenario poses a higher risk of damage from over pressure experienced during a deflagration and therefore both the ventilation and clearances are increased.