BAL rating and BAL assessment: what the levels mean

A BAL rating, short for bushfire attack level, is the grade of bushfire attack a building has to be designed for, and a BAL assessment is how that grade is worked out for one site. There are six levels, from BAL-LOW to BAL-FZ, the flame zone, as per AS 3959, and the rating for a site comes from the vegetation near it, the slope of the land under that vegetation and the distance between them.

To check one block, type its address into RapidSiteplan: it reads the lot and the rules that apply there and checks the structure you place against them, in minutes.

What do the bushfire attack levels mean?

Level	What the site faces	What it asks of the building
BAL-LOW	Too little risk to set requirements	No bushfire construction requirements
BAL-12.5	Ember attack, with low radiant heat	Sealed gaps, screened vents and openings, and materials embers will not catch
BAL-19	More ember attack, burning debris and rising radiant heat	The same list, with tougher materials and glazing
BAL-29	Ember attack, burning debris and higher radiant heat	Requirements that tighten hard on walls, windows, decks and roofs
BAL-40	Radiant heat high enough that flames may reach the building	Construction close to the strictest, with tested window and door systems
BAL-FZ	The flame zone: direct contact with the fire front	The strictest construction in AS 3959, and in some states a limit on new homes

The rating belongs to the site, not the suburb. Bushfire-prone does not mean a fire is coming. It means the land sits where bushfire attack is possible, and buildings there have to be designed to survive it.

What does BAL-12.5 mean?

BAL-12.5 is the first level that brings construction requirements. It is set for ember attack with low radiant heat, so the work starts with sealing gaps, screening vents and openings, and choosing materials that embers will not catch. BAL-19 adds to the same list, and from BAL-29 the requirements tighten hard.

What is a BAL assessment?

A BAL assessment works out the level for one building site. The assessor maps the vegetation within reach of the site, measures the slope under it and the distance to the building, and reads the level from the method in AS 3959. A bushfire consultant does it, or for simpler sites the certifier, and the result decides how the building is built. Where the site is close to a level’s edge, moving the building further from the vegetation can bring it down a level, so the assessment belongs before the design settles.

Where is the bushfire prone land map?

The levels are national, but every state draws its own map of where they apply, under its own name, and the name matters when you search for it.

State	What the map is called	What it brings
Queensland	Bushfire prone area, mapped in each council’s planning scheme, usually as a bushfire hazard overlay	A BAL for a new house, an addition or an attached structure, and the overlay’s own planning questions
New South Wales	Bush fire prone land, mapped for each council and certified by the state’s fire service	A BAL for the building, and an assessment of the development for bush fire protection
Victoria	Bushfire prone area for building, and a bushfire management overlay for planning	A BAL for the building, and a planning permit where the overlay applies
South Australia	Bushfire hazard overlays in the state’s planning code	Construction to the level the overlay and the site call for
Western Australia	Bush fire prone areas, designated on a state map	A BAL for the building, and a bushfire assessment for planning
Tasmania	Bushfire-prone areas in the planning scheme	A BAL for the building, and a bushfire hazard management plan where one is needed
ACT	The territory’s bushfire prone area map	Bushfire construction for buildings inside it
Northern Territory	Ask the certifier whether a mapped area applies to the lot	Bushfire construction where it does

RapidSiteplan shades the mapping over your real lot and warns you when a proposed structure lands in a mapped area, before the design settles, and the bushfire prone check reads it for an address.

Does a BAL assessment work differently in Queensland?

The method is the same, since the standard is national; what differs is the map that triggers it. In Queensland the trigger is the bushfire prone area in the council’s planning scheme, usually drawn as a bushfire hazard overlay, and the certifier asks for the level for a new house, an addition or an attached structure on that land. The Queensland page covers how the council and the certifier split the work.

Does a patio, deck or shed need a BAL assessment?

Often, on mapped land. Attached structures and anything near the house can change the dwelling's exposure, and a timber deck against a wall is the classic trigger. Expect your certifier to ask for a BAL assessment, and expect the material and detailing requirements to follow whatever rating comes back.

What is the flame zone?

The flame zone, BAL-FZ, is the top of the scale: a site close enough to the vegetation that flames can reach the building. Construction there is the strictest the standard sets, and planning rules in some states limit new homes at that level.

What only your address can answer

whether the lot is inside the mapped bushfire-prone area
the vegetation around the site, the slope of the land, and how far apart they are
the rating the building has to be designed for, which an assessment of the site sets
whether a planning overlay adds bushfire requirements of its own

RapidSiteplan reads your block from its address: the boundaries, the buildings already on it, the rules that apply there and any overlay or easement, and checks what you plan to build against them on a scaled site plan.

Search your address to start. Site plans and assessments in minutes.

Common questions

What does a BAL rating mean? A BAL rating, short for bushfire attack level, is the grade of bushfire attack a building has to be designed for. The six levels are BAL-LOW, BAL-12.5, BAL-19, BAL-29, BAL-40 and BAL-FZ, the flame zone, and the higher the level, the stricter the construction as per AS 3959.

What does BAL-12.5 mean? BAL-12.5 is the first level that brings construction requirements, set for ember attack with low radiant heat. Sealing gaps, screening vents and openings and choosing materials that embers will not catch are where it starts, and the assessment confirms the level for the site.

What is a BAL assessment? A BAL assessment works out the bushfire attack level for a building site from the vegetation around it, the slope of the land and the distance between them. A bushfire consultant or, for simpler sites, the certifier does it, and the result sets how the building has to be built.

Do I need a BAL assessment in Queensland? On land the council’s planning scheme maps as a bushfire prone area, yes: the certifier needs the level for a new house, an addition or an attached structure there. The method is the same as in the other states, because the standard is national.

What is the flame zone? The flame zone, BAL-FZ, is the top of the scale: a site close enough to the vegetation that flames can reach the building. Construction there is the strictest the standard sets, and planning rules in some states limit new homes at that level.

Where is the bushfire prone land map? Each state publishes its own, under its own name, and many councils carry it as an overlay in the planning scheme. RapidSiteplan shades the mapping over your lot and warns you when a proposed structure lands in a mapped area.