Section 7 - AS 3959:2018
Construction Requirements for BAL 29
Sections 3 & 5
​
Ember attack
radiant heat
below 12.5kW/m2.
Sections 3 & 6
​
Increasing ember attack and windborne debris, radiant heat between 12.5kW/m2
and 19kW/m2.
Sections 3 & 7
Increasing ember attack and windborne debris, radiant heat between 19kW/m2
and 29kW/m2.
Sections 3 & 8
​
Increasing ember attack and windborne debris, radiant heat between 29kW/m2
and 40kW/m2. Exposure to flames
from a fire front likely.
Sections 3 & 9
​
Direct exposure to flames, radiant heat and embers from
the fire front.
Section 7 - AS 3959:2018
BAL 29 Reference Guide
Refer to Sections 3 & 7 for all BAL 29 Requirements
This reference guide is not an exhaustive list of all of the requirements of AS3959:2018, and should be read in conjunction with Australian Standards AS3959:2018, AS1530.8.1, AS1530.8.2 and official test reports and assessments.
Link to 'Bushfire resisting timber'
BAL 29 - General (Clause 7.1)
A building assessed as being BAL 29 shall conform with Section 3 (General Construction Requirements) and Clauses 7.2 to 7.8 of AS3959:2018.
Any element of construction or system that satisfies the test criteria of AS1530.8.1 may be used in lieu of the applicable requirements contained within Clauses 7.2 to 7.8 (see Clause 3.8).
BAL 29 - Subfloor Supports (Clause 7.2)
- Unenclosed Subfloors.
Supports (stumps, etc.) shall be (a) non-combustible, or (b) bushfire resisting timber.
- Enclosed Subfloors.
No requirements if the subfloor is enclosed with a cladding that conforms with the wall requirements (sarking not required behind subfloor cladding).
BAL 29 - Floors (Clause 7.3)
- Unenclosed Subfloors.
No requirements for bearers and joists with more than 400mm clearance above the ground, if closer than 400mm, bearers and joists shall be (a) non-combustible, or (b) bushfire resisting timber, and the flooring shall be (a) non-combustible, or (b) bushfire resisting timber, or (c) timber, particleboard or plywood with a sarking type material, or mineral wool insulation.
- Enclosed Subfloors.
No requirements if the subfloor is enclosed with a cladding that conforms with the wall requirements (sarking is not required behind the subfloor cladding).
BAL 29 - Walls (Clause 7.4)
Walls shall be (a) non-combustible (including brick, concrete, rammed earth and mud brick, etc. at min. thickness of 90mm), or (b) timber logs of a certain density, or (c) cladding on sarked walls that is (i) non-combustible, or (ii) min. 6mm thick cement sheet, or (iii) steel sheeting, or (iv) bushfire resisting timber.
Any gaps greater than 2mm to be screened with 2mm mesh in corrosive resistant steel, bronze or aluminium.
BAL 29 - Windows & Doors (Clause 7.5)
The three options are (a) be completely protected by a bushfire shutter, or (b) a window or door system tested to conform with AS1530.8.1, or (c) a 'Deemed To Satisfy' (DTS) option.
(a) Bushfire Shutters.
Bushfire shutters can be used to protect non compliant windows and doors that are not tested to AS1530.8.1, and do not meet DTS requirements. Where fitted, they must conform with Clause 3.7 and be made from (a) non-combustible material, or (b) bushfire resisting timber.
(b) Tested System.
Refer to window and door manufacturers for options.
(c) Deemed To Satisfy.
Frames...
Window and door frames shall be (a) bushfire resisting timber, or (b) metal (inc. aluminium), or (c) metal reinforced uPVC.
Glazing...
Grade A safety glass with a min. thickness of 5mm for windows, and a min. thickness of 6mm for doors.
Note - Any low level window glazing (within 400mm of the ground, decks, or roofs less than 18 degrees, etc.) shall be screened externally and made from (a) metal, or (b) bushfire resisting timber, and have 2mm mesh or perforated sheet in corrosive resistant steel, bronze or aluminium.
Note - Low level door glazing does not require screens.
Screens... (insect screens with ember mesh)
Openable windows require screens (fitted internally or externally).
Openable doors do not require screens.
Screens fitted shall be made from (a) metal, or (b) bushfire resisting timber, and have 2mm mesh or perforated sheet in corrosive resistant steel, bronze or aluminium.
- Garage Doors.
Garage doors shall be (a) non-combustible, or (b) bushfire resisting timber, or (c) 6mm cement sheet, and requires door seals to meet Section 3 of AS3959:2018.
BAL 29 - Roofs (Clause 7.6)
- General.
Any roofing materials, systems or accessories shall be (a) non-combustible, and (b) sealed in accordance with AS3959:2018 Clause 3.6, and (c) any roof vents fitted with ember guards with 2mm mesh or perforated sheet in corrosive resistant steel, bronze or aluminium.
- Fascias & Eaves.
Fascias & bargeboards shall be (a) bushfire resisting timber, or (b) metal fixed at every 450mm.
Eave lining shall be (a) min. 4.5mm thick cement sheet, or (b) bushfire resisting timber.
Fascias and eave gaps to be fitted with 2mm mesh or perforated sheet in corrosive resistant steel, bronze or aluminium.
- Tiled Roofs.
Tiled roofs to be fully sarked and shall (a) be located on top of roof framing, except battens may be fixed above the sarking, and (b) cover the entire roof, inc ridges and hips, and (c) extend into gutters and valleys.
- Sheet Roofs.
Sheet roofs to be fully sarked and shall (a) be located on top of roof framing, except battens may be fixed above the sarking or foil backed insulation blankets may be installed over the battens, and (b) cover the entire roof, inc ridges and hips, and (c) extend into gutters and valleys, and (d) have any gaps sealed at the fascia or wall line, hips and ridges by (i) 2mm mesh or perforated sheet in corrosive resistant steel, bronze or aluminium, or (ii) mineral wool, or (iii) other non-combustible material.
- Downpipes & Gutters.
No requirements for downpipes.
Gutters shall be (a) metal, or (b) uPVC.
Box gutters shall be non-combustible, and flashed with non-combustible materials.
- Gutter Guards.
No requirement to install gutter or valley guards, but if they are fitted shall be non-combustible.
- Skylights.
Refer to AS3959:2018 for requirements of skylight flashing and glazing.
- Roof Penetrations.
Refer to AS3959:2018 for requirements of roof penetrations such as skylights, evaporative coolers, vent pipes, aerials and support brackets, etc as there are many.
BAL 29 - Verandahs, Decks, Stairs (Clause 7.7)
- Verandah & Carport Roofs.
Verandah and carport roofs shall meet the roof requirements of the main roof, or be separated by an external wall conforming with the wall requirements and shall have non-combustible roof covering, and the complete support structure shall be (a) non-combustible material, or (b) bushfire resisting timber, or (c) timber rafters lined on the underside with min. 6mm cement sheet or material conforming with AS1530.8.1
- Verandah & Carport Posts.
Verandah and carport posts shall be (a) non-combustible, or (b) bushfire resisting timber.
- Unenclosed Deck Supports & Framing.
Deck supports and framing shall be (a) non-combustible, or (b) bushfire resisting timber.
- Enclosed Deck Supports & Framing.
If the subfloor is enclosed, it must be enclosed to match the wall requirements, and there are no requirements for the supports and framing.
- Decking Boards, Stairs & Ramps.
Decking boards, stair treads, landings and ramps shall be (a) non-combustible, or (b) bushfire resisting timber.
- Balustrades.
Balustrades, handrails and other barriers within 125mm of any glazing or combustible wall, shall be (a) non-combustible, or (b) bushfire resisting timber.
BAL 29 - Water & Gas Pipes (Clause 7.8)
Above ground exposed water supply pipes shall be metal, external gas pipes and fittings above ground shall be of steel or copper with a min. wall thickness in accordance with gas regulations or 0.9mm, whichever is the greater and shall extend a min. of 400mm within the building and 100mm below ground.
