NCC 2019 Volume One
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Part G2 Boilers, pressure vessels, heating appliances, fireplaces, chimneys and flues
GP2.1 Combustion heating appliances
Where provided in a building, a combustion appliance and its associated components, including an open fire-place, chimney, flue, chute, hopper or the like, must be installed—
(a)
to withstand the temperatures likely to be generated by the appliance; and
(b)
so that it does not raise the temperature of any building element to a level that would adversely affect the element’s physical or mechanical properties or function; and
(c)
so that hot products of combustion will not—
(i)
escape through the walls of the associated components; and
(ii)
discharge in a position that will cause fire to spread to nearby combustible materials or allow smoke to penetrate through nearby windows, ventilation inlets, or the like.
The Objective of this Part is to—
(a)
safeguard occupants from illness or injury caused by—
(i)
fire from combustion appliances installed within a building; and
(ii)
malfunction of a boiler or pressure vessel installed within a building; and
(b)
protect a building from damage caused by the malfunction of a boiler or pressure vessel installed within.
Combustion appliance—GO2(a)(i)
GO2(a)(i) specifies that people must be protected from injury by fire from a combustion appliance. GO2(a)(i) applies only to combustion appliances installed within a building.
Boilers and pressure vessels—GO2(a)(ii)
GO2(a)(ii) specifies that people must be protected from injury caused by a malfunction of a boiler or pressure vessel. GO2(a)(ii) applies only to boilers or pressure vessels installed within a building.
The malfunction of a boiler or pressure vessel could create steam and/or an explosion.
Protection of building—GO2(b)
GO2(b) requires that a building intended to contain a boiler or pressure vessel be designed so that any fault to the boiler or pressure vessel will not damage the building. The aim is to make sure that the structural stability of the building is not affected.
Combustion appliances using controlled combustion located in a building are to be installed in a way which reduces the likelihood of fire spreading beyond the appliance.
Combustion appliances
GF2.1 requires that a heating system be installed to prevent fire spreading to adjoining building elements.
A key expression in GF2.1 is “controlled combustion”. This expression means that only heating units which burn solid materials or oil must comply with these provisions. The expression applies to open fireplaces, oil heaters, solid-fuel burning stoves, coal heaters,pot-belly stoves, and other such cooking and heating devices.
The expression does not include electric heaters. Nor is it intended to include gas heaters, covered by other State and Territory legislation.
Boilers and pressure vessels located in a building are to be installed in a manner which will provide adequate safety for occupants.
When installed in a building, a combustion appliance (including all associated components) must be:
- designed to be robust enough to operate under all applicable heating conditions. It is particularly important that flue systems comply with this requirement, so they are compatible with the primary heating unit;
- installed so that, when in operation, the radiated heat will not affect adjoining building elements (i.e. burn timber, warp steel lintels, char plasterboard and so on). This not only applies to the actual heating unit, but also to the attached flues, especially where they pass through other areas of the building (such as roofs, ceiling spaces, walls and the like); and
- designed and installed so that the hot products of combustion are properly discharged in a manner which will not cause damage. To do this, builders must make sure flues are adequately joined to create a continuous discharge route. The discharge point must be such that discharged products will not re-enter the building. They should not ignite adjoining combustible materials where the appliance is installed.
GP2.2 Boilers and pressure vessels
When located in a building, boilers and pressure vessels must be installed to avoid, during reasonably foreseeable conditions, the likelihood of—
(a)
leakage from the vessel which could cause damage to the building; and
(b)
rupture or other mechanical damage of the vessel which could cause damage to the building or injury to occupants.
Because of the dangers of boilers and pressure vessels, care has to be taken during installation. Boilers and pressure vessels located outside a building are not covered by the BCA, but may be controlled by other State and Territory legislation.
Issues such as leakage of pressurised liquids and the consequences of the vessel being damaged must be considered. Damage must be avoided to the vessel. Such damage could occur if the vessel is located in an area subject to traffic.
Verification Methods
GV2 Combustion appliances
Compliance with GP2.1(a) and GP2.1(b) is verified when—
(a)
components used within an appliance and its installation are constructed from—
(i)
heat-resistant materials for maximum operating temperatures not less than 600℃, where the material complies with (c); or
(ii)
heat-tolerant materials for maximum operating temperatures more than 150℃ and less than 600℃, where the material complies with (c); and
(b)
the building elements surrounding the appliance maintain their designed function and material properties inclusive of a full range of thermal movements when exposed to the heat effects of the appliance; and
(c)
a sample of the material is tested to the maximum operating temperature, specified in (a)(i) or (a)(ii) for a minimum of 96 hours and the tested sample complies with the following:
(i)
When allowed to cool, the tested sample must be free from—
(A)
visible cracks and fractures; and
(B)
visible indication of de-lamination; and
(C)
linear distortion in excess of the equivalent of 10 mm per metre, and
(D)
deterioration of the appearance of any surface finish, when compared to an unheated sample.
Under GV2, it need to be demonstrated that the proposed appliance will not deteriorate under standard operating conditions. Examples of deterioration may include deformation or failure of components that would render the appliance unsafe to use.
For the purposes of demonstrating compliance with sub-clause (a), the typical operating temperature of a combustion device can be established by testing.
For the purposes of demonstrating compliance with sub-clause (b), materials used for building elements (walls, floors and ceiling) in the areas surrounding an appliance can be appropriately selected and/or designed to align with the quantified values as determined by sub-clause (a). This could either be achieved by using the expert judgement of an engineer or by adhering to manufacturer’s specifications. Certification in accordance with CodeMark Australia would also be a possibility in demonstrating compliance using the Verification Method. Full range of thermal movements relates to both the appliance and materials when exposed to both the heated and ambient conditions.
Benefits to industry derived from the application of this Verification Method include the potential use of non-standard national or internationally manufactured appliances. For example, test reports for appliances complying with various ISO Standards and various British Standards could be used to demonstrate compliance with the Verification Method. The Verification Method also allows for in situ testing of unique combustion appliances, which would not easily be tested in accordance with the Australian Standard. Such testing would need to be verified by a suitably qualified practitioner and be supported by appropriate documentation.