Section 5 - AS 3959:2018

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 12.5 - General (Clause 5.1)

A building assessed as being BAL 12.5 shall conform with Section 3 (General Construction Requirements) and Clauses 5.2 to 5.8 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 5.2 to 5.8 (see Clause 3.8).

 

 

BAL 12.5 - Subfloor Supports (Clause 5.2)

- Unenclosed Subfloors.

Supports (stumps, etc.) shall be (a) non-combustible, or (b) bushfire resisting timber, or (c) a timber species with a density of 750kg/m³ or greater.

 

- 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 12.5 - Floors (Clause 5.3)

- 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 12.5 - Walls (Clause 5.4)

No requirements for wall cladding above 400mm from the ground, decks, carport roofs, awnings or similar. 

 

Any walls within 400mm from the ground, decks, carport roofs, awnings or similar, 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 that is (i) non-combustible, or (ii) min. 6mm thick cement sheet, or (iii) bushfire resisting timber, or (iv) a timber species with a density of 750kg/m³ or greater, or (v) steel sheeting.

 

Any gaps greater than 2mm to be screened with 2mm mesh in corrosive resistant steel, bronze or aluminium.

 

 

BAL 12.5 - Windows & Doors (Clause 5.5)

The four options are (a) be completely protected by a bushfire shutter, or (b) be completely protected externally by screens, or (c) a window or door system tested to conform with AS1530.8.1, or (d) 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 Clause 5.5.1.

 

(b) Fully Screened.

External screens can be used to completely protect non compliant windows and doors that are not tested to AS1530.8.1, and do not meet the DTS requirements. Where fitted, they must conform with Clause 3.6 and Clause 5.5.2. 

 

Screens to be made from (a) non-combustible material, or (b) bushfire resisting timber, or (c) a timber species with a density of 750kg/m³ or greater. 

Screens to be 2mm mesh or perforated sheet in corrosive resistant steel, bronze or aluminium.

 

(c) Tested System.

Refer to window and door manufacturers for options.

 

(d) Deemed To Satisfy.

Frames...

Window and door frames shall be (a) bushfire resisting timber, or (b) a timber species with a density of 750kg/m³ or greater, or (c) metal (inc. aluminium), or (d) metal reinforced uPVC.

 

Glazing...

Grade A safety glass with a min. thickness of 4mm.

 

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, or (c) (internally only) a timber species with a density of 750kg/m³ or greater, 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) a timber species with a density of 750kg/m³ or greater, and requires door seals to meet section 3 of AS3959:2018

 

 

BAL 12.5 - Roofs (Clause 5.6)

- 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 and Eaves.

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 or gutters. 

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 AS 3959:2018 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 12.5 - Verandahs, Decks, Stairs (Clause 5.7)

- 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, except where the roof covering is translucent or transparent material.

 

- Verandah & Carport Posts.

Verandah and carport posts shall be (a) mounted on galvanised brackets with a clearance of not less than 75mm above the adjacent finished ground level, or (b) if within 400mm from the ground or deck, etc to be (i) non-combustible, or (ii) bushfire resisting timber, or (iii) a timber species with a density of 750kg/m³ or greater.

 

- Deck Supports & Framing.

Decks have no requirements for supports or framing (except for posts for verandahs or carports). There are no requirements to enclose the sub floor of a deck, but if enclosed any material used to enclose a subfloor space within 400mm of the ground shall match the wall requirements.

 

- Decking Boards, Stairs & Ramps.

Decking boards, stair treads, landings and ramps have no requirements if they are further than 300mm from glazed elements (windows and doors) that are less than 400mm above that surface. 

 

Any decking boards, stair treads, landings or ramps within 300mm of glazed elements shall be (a) non-combustible, or (b) bushfire resisting timber, or (c) a timber species with a density of 750kg/m³ or greater.

 

- Balustrades.

Balustrades, handrails or other barriers have no requirements.

 

 

BAL 12.5 - Water & Gas Pipes (Clause 5.8)

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.