Part 3.10.7 Boilers, pressure vessels, heating appliances, fireplaces, chimneys and flues
Appropriate Performance Requirements
Appropriate Performance Requirements
Acceptable Construction Manuals
Acceptable Construction Practice
18.104.22.168 Open fireplace construction
An open fireplace, or solid-fuel burning appliance in which the fuel-burning compartment is not enclosed must have—
all masonry constructed in accordance with Part 3.3; and
a hearth constructed of stone, concrete, masonry or similar non-combustible material so that—
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
its upper surface does not slope away from the back hearth; and
walls forming the sides and back of the fireplace up to a height of 300 mm above the underside of the arch or lintel which—
are constructed in 2 separate leaves of solid masonry not less than 180 mm thick, excluding any cavity; and
do not consist of concrete block masonry in the construction of the inner leaf; and
are 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; and
the fireplace must be constructed on footings complying with 22.214.171.124.
126.96.36.199 Chimney construction
The construction of a chimney must comply with Part 3.3 and the following:
The walls of the chimney above the level referred to in 188.8.131.52(c) must be lined internally to a thickness of not less than 10 mm with composition mortar parging.
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 184.108.40.206).
220.127.116.11 Installation of insert fireplaces and flues
An insert fireplace and flue must comply with the following:
The insert fireplace must be tested and passed the tests required by AS/NZS 2918.
The insert fireplace must be fitted into a masonry fireplace (including chimney) constructed in accordance with Part 3.3.
The flue must be double skin and have been tested and pass the tests required by AS/NZS 2918.
There must be a clearance of 50 mm between the outer flue and adjacent materials.
The flue must terminate in accordance with Figure 18.104.22.168.
22.214.171.124 Installation of free standing heating appliances
The installation of a free standing heating appliance must comply with the following:
The appliance must—
be installed with safety clearances determined by testing in accordance with AS/NZS 2918; or
be located not less than 1.2 m from adjoining walls (other than a masonry wall); or
have a heat shield between the adjoining wall (other than a masonry wall) and the heating appliance in accordance with Figure 126.96.36.199 Diagrams a and b.
Note to Figure 188.8.131.52: Flue pipe size — 150 mm maximum (for other sizes see AS/NZS 2918).
184.108.40.206 Installation of boilers and pressure vessels
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 220.127.116.11.
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
Building elements surrounding a boiler must be protected from any furnace heat by refractory material or effective air spaces so that—
steel elements do not exceed a temperature of more than 300°C; and
concrete elements do not exceed a temperature of more than 200°C; and
timber elements do not exceed a temperature of more than 150°C.
The requirements of 18.104.22.168 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.
Table 22.214.171.124 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.