Adelaide block check
BAL (Bushfire Attack Level) Assessment: What It Means for Your Adelaide Home
Quick answer
A Bushfire Attack Level (BAL) assessment rates a home's exposure to a bushfire on a six-level scale: BAL-LOW, BAL-12.5, BAL-19, BAL-29, BAL-40, and BAL-FZ (Flame Zone). It is required in South Australia when the block sits in a Hazards (Bushfire) Overlay on SAPPA, and it drives construction standards under AS 3959.
Adelaide is a fire-prone city on its metropolitan fringes. Any block in a Hazards (Bushfire) Overlay will need a BAL assessment before the design is finalised. The BAL rating determines the construction standards your home must meet under Australian Standard AS 3959.
Public source: CFS SA: Planning and building in bushfire areasBushfire assessment
How to get a BAL assessment for an Adelaide block
- 1
Check SAPPA for the Bushfire overlay
Search your address on sappa.plan.sa.gov.au and look for a Hazards (Bushfire) Overlay in the right-hand panel.
- 2
Engage a bushfire consultant
If the overlay applies, engage a qualified bushfire consultant (BPAD accredited or equivalent). Any competent Adelaide Hills builder or building designer has a consultant they use.
- 3
Vegetation and slope survey
The consultant classifies the vegetation type within 100 metres of the proposed home footprint, measures effective slope, and applies the region's fire danger index.
- 4
Receive the BAL rating
The report returns one of BAL-LOW, BAL-12.5, BAL-19, BAL-29, BAL-40, or BAL-FZ. The number is radiant heat flux in kW per square metre.
- 5
Feed the rating into the design
Give the report to your building designer or builder before drawings are finalised. Ember protection, glazing, cladding, decking, and gutter details all change with BAL level under AS 3959.
Watch: Homes By Homes podcast, episode 47
What does Bushfire Attack Level (BAL) mean in your quote?
A dedicated deep-dive on how BAL ratings translate into real build detailing and quote line items.
Section 1
What BAL stands for
Bushfire Attack Level. Six levels: BAL-LOW, BAL-12.5, BAL-19, BAL-29, BAL-40, and BAL-FZ (Flame Zone). The number represents radiant heat flux in kW per square metre. Higher BAL means the home must be built to withstand more intense fire conditions.
Section 2
What triggers a BAL assessment
The block sits in a Bushfire Hazards Overlay on SAPPA. Very common in Adelaide Hills, Adelaide Foothills, and outer metro edges near reserves. If SAPPA shows the overlay, an assessment is required as part of the planning consent.
Section 3
How BAL is calculated
A bushfire consultant assesses: the classified vegetation type within 100 metres of the house, the effective slope of that vegetation, and the fire danger index for the region. Grassland, forest, and woodland classifications each produce different results. Slope down toward the vegetation dramatically increases risk.
Section 4
What each BAL level requires (in outline)
BAL-LOW: standard construction, no bushfire measures needed. BAL-12.5: ember protection, screened openings. BAL-19: stronger ember protection plus radiant heat measures. BAL-29: significant construction upgrades including window glazing and cladding. BAL-40: heavy protection, restricted materials, sarking under roof tiles. BAL-FZ: fire-resistant construction throughout, often the design threshold at which a project needs to be reconsidered.
| BAL level | Radiant heat | Exposure | Typical construction focus |
|---|---|---|---|
| BAL-LOW | Under 12.5 kW/m2 | Insufficient risk to warrant specific construction | No AS 3959 requirements beyond BCA baseline |
| BAL-12.5 | Up to 12.5 kW/m2 | Ember attack | Ember protection, gutter guards, mesh vents |
| BAL-19 | Up to 19 kW/m2 | Increasing ember + radiant heat | Above plus toughened glazing, non-combustible cladding on exposed walls |
| BAL-29 | Up to 29 kW/m2 | Ember + heavy radiant heat | Above plus bushfire-rated windows, doors and decking |
| BAL-40 | Up to 40 kW/m2 | Radiant heat plus limited direct flame | Above plus fire shutters, upgraded roof-to-wall junctions, sarking |
| BAL-FZ | Over 40 kW/m2 | Direct exposure to flame | Bespoke bushfire-engineered envelope; specialist detailing required |
Section 5
How BAL affects design choices
Higher BAL levels drive material selections: non-combustible cladding, tempered glass windows, ember-proof gutters, no exposed timber decking within 6 metres of the house, screened underfloor spaces, and sometimes sprinkler systems. Lower BAL is manageable within a standard build; BAL-40 and above changes the design meaningfully.
Section 6
What to do
Commission a BAL assessment before you finalise a design, not after. A BAL consultant costs a fraction of redoing drawings once construction requirements are known. Any competent Adelaide Hills builder or building designer will have a consultant they use routinely.
What to do next
Keep reading
Find a town planner
Overlay-heavy block? A planner reads the code and pre-lodges advice.
Learn moreFind a private certifier
Ready for Planning + Building Rules Consent? A certifier can move fast.
Learn moreFind a building designer
Need drawings that respect the overlay? Start with a designer.
Learn moreCouncil approvals in Adelaide
The full pillar covering PlanSA, DCS levies, and the council pathway.
Learn moreThis is general planning and technical information drawn from public sources. It is not legal, planning, or engineering advice. Rules and overlays change; always confirm current requirements directly through SAPPA and engage a qualified professional (town planner, building designer, private certifier, arborist, or geotechnical engineer) for your specific block.