What is the difference between the BMO and a BPA?

The Bushfire Management Overlay (BMO) is a planning control: if it applies, you usually need a planning permit with CFA referral before the building permit. A designated Bushfire-Prone Area (BPA) is a building control: if your land is mapped as BPA, the home must be built to at least BAL-12.5 even without a BMO. Many blocks are affected by one, some by both.

Who assesses bushfire in Victoria, the council or the CFA?

Your council is the responsible authority for a BMO planning permit, but it refers the application to the Country Fire Authority (CFA) for comment. The CFA assesses defendable space, access, water supply and the proposed BAL. A private or municipal Relevant Building Surveyor then handles the building permit to AS 3959.

Which Melbourne builders build to BAL requirements?

BuildPilot is independent and matches you only with vetted Victorian partner builders. The specialist pool for BAL-29 and above is smaller; request a private match and we will shortlist builders experienced with your overlay.

Bal Ratings Vic Guide

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How-to guide · Supporting Bushfire Builders

Understanding BAL ratings in Victoria

The Bushfire Attack Level of your block sets the minimum construction standard, the cost premium and often whether you need a planning permit at all. Here is what each BAL rating means and how they are assigned in Victoria.

Last reviewed by BuildPilot · 24 June 2026

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In brief

Bushfire Attack Level (BAL) is the national classification that sets construction standards for building in bushfire-prone areas. In Victoria it matters most in the Dandenong Ranges, the Yarra Ranges, Nillumbik, Macedon Ranges, parts of Cardinia and Mitchell, and along the Surf Coast and Mornington Peninsula.

Victoria adds two planning layers on top of the national standard: the Bushfire Management Overlay (BMO) in the planning scheme, and designated Bushfire-Prone Areas (BPA) in the Building Regulations. This guide explains what each BAL level means and how the rating is assigned to a specific block.

Key takeaways

1BAL ratings run from BAL-LOW through BAL-12.5, 19, 29, 40 and BAL-FZ (Flame Zone), set under AS 3959-2018.
2In Victoria the Bushfire Management Overlay (BMO) and designated Bushfire-Prone Areas (BPA) decide whether BAL construction and a planning permit apply.
3BAL is determined by the Fire Danger Index, vegetation type, distance to vegetation and slope.
4A BMO planning permit is assessed by your council with referral to the CFA.

STEP 1

1. The six BAL levels and what each means

The BAL scale under AS 3959-2018 defines six levels of bushfire attack severity.

BAL-LOW: insufficient risk to require specific bushfire construction measures.

BAL-12.5: ember attack is the primary threat. Window screens, ember-proof roof detailing and non-combustible materials in vulnerable areas.

BAL-19: ember attack plus radiant heat up to 19 kW/m2. Some wall and roof cladding restrictions.

BAL-29: ember attack plus radiant heat up to 29 kW/m2. Bushfire-resistant materials for walls, roof, windows and doors.

BAL-40: severe radiant heat up to 40 kW/m2 plus embers. Very restrictive material requirements and a material cost increase.

BAL-FZ (Flame Zone): direct flame contact possible. Highest protection, typically steel-framed construction and radiant-heat barriers.

STEP 2

2. How the BAL rating is assigned to your block

A BAL assessment is a technical assessment done by an accredited bushfire consultant, considering four factors.

First, the Fire Danger Index for your area, set by Victorian legislation.

Second, the classification of surrounding vegetation (forest, woodland, shrubland, grassland or none) within a defined distance.

Third, the distance from classified vegetation to the proposed building. Closer vegetation raises the BAL.

Fourth, the slope between the vegetation and the building. Steeper upslopes raise the BAL because fire runs uphill faster.

For a BMO planning permit, the assessment is usually presented as a Bushfire Management Statement and may propose defendable space and a bushfire attack level for the building envelope.

STEP 3

3. What a BAL rating costs you in Victoria

BAL-12.5 and BAL-19 typically add a modest premium (screens, sarking, ember detailing).

BAL-29 is where costs step up: bushfire-rated windows, restricted cladding and specific decking and subfloor details.

BAL-40 and BAL-FZ require certified rated systems and specialist builders; the premium can be substantial and lead times longer.

The BAL also affects defendable space and vegetation management conditions on your title, which can shape where the house can sit on the block.

FAQs

A BAL assessment is required where your land is in a designated Bushfire-Prone Area (BPA) under the Building Regulations, or where a Bushfire Management Overlay (BMO) applies in the planning scheme. Check your parcel on VicPlan and confirm with your council duty planner.

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