Building in Bushfire Prone Areas

Bushfires pose a serious threat to people, property, infrastructure and the environment. They can start suddenly and with the right weather conditions, move very quickly, causing widespread devastation. Bushfires can leave a lasting impact on communities. Find out about laws, regulations and approvals that may relate to you, if you are located in a bushfire prone area together with the State Government’s new bushfire land use development reforms to manage and reduce the risk of bushfire across the State.

What are the laws for building in bushfire prone areas and how do they affect me?

The Building Act 2011 and Building Regulations 2012 cite the Building Code of Australia (BCA) as the primary applicable building standard for all buildings and incidental structures in Western Australia. The BCA sets out the minimum construction requirements for all classes of buildings, and includes specific requirements for residential buildings in bushfire prone areas.

If you intend to build a new home or carry out substantial additions or alterations to an existing residential building located within a designated bushfire prone area identified on the Map of Bushfire Prone Areas, your application for a building permit must clearly address compliance with the bushfire construction requirements of the BCA and Australian Standard AS3959 – 2009 Construction of Buildings in Bushfire-Prone Areas.

What types of buildings need to comply with bushfire regulations?

The Building Code of Australia bushfire construction requirements apply to the following classes of residential buildings located within designated bushfire prone areas:

  • Class 1 – Single dwellings: bed and breakfast, hostels, guest houses or similar
  • Class 2 – A building containing two or more sole-occupancy units, each being a separate dwelling (e.g. apartments, flats or similar)
  • Class 3 – A residential building (other than a Class 1 or Class 2 building) such as hotels,  accommodation for aged, children or people with disabilities or similar
  • Class 10a buildings and decks associated with Class 1, Class 2 or Class 3 buildings. Class 10a buildings include non-habitable buildings such as carports, sheds, garages or similar.

Please visit the Department of Mines, Industry Regulation and Safety website (formerly Building Commission) for more information on building in bushfire prone areas.

Map of bushfire prone areas

Bushfire prone areas in Western Australia are designated by the Fire and Emergency Services Commissioner and are identified on the Map of Bushfire Prone Areas. Properties that are located within, or partially within, designated bushfire prone areas are highlighted in pink on the map. You can refer to this map to find out whether your property is within a designated bushfire prone area.

What is a Bushfire Attack Level (BAL)?

Australian Standard AS3959 – 2009 - Construction of Buildings in Bushfire-Prone Areas provides an assessment method for assigning a Bushfire Attack Level (BAL) for a site.

BALs are a measure of the severity of a building’s potential exposure to ember attack, radiant heat and direct flame contact. BALs help to determine the appropriate bushfire construction requirements. There are six (6) BAL categories, as set out in AS 3959-2009:

  • BAL-Low – very low risk (bushfire resistant construction not required)
  • BAL-12.5 – low risk
  • BAL-19 – moderate risk
  • BAL-29 – high risk
  • BAL-40 – very high risk
  • BAL-FZ – extreme risk (Flame Zone).

What is a Bushfire Attack Level (BAL) Contour Map?

A BAL Contour Map is a scale map of a development / subdivision site, including the proposed lot layout, which shows indicative BAL ratings across the site and within the immediate surrounding area. This helps to identify areas at risk from bushfires, ensuring appropriate risk management is incorporated into the subdivision design and lot layout. A BAL Contour Map is generally prepared to facilitate a planning land subdivision process. A BAL Contour Map can be used in support of a Planning Structure Plan or planning land subdivision application.  

What is a Bushfire Attack Level (BAL) assessment?

A site specific assessment of a property’s Bushfire Attack Level (BAL) takes into consideration a number of factors:

  • Slope of the land
  • Types of surrounding vegetation
  • Distance of the building to that vegetation.

Generally carried out by an accredited Level 1 BAL Assessor, a site specific assessment will determine the BAL of the site and the level of bushfire resistant construction required for the building. The BAL assessment is used in support of a Building Permit application.

Visit the Fire Protection Association Australia website to find an accredited BAL Assessor.

Indicative BAL ratings versus Site Specific BALs

BAL Contour Maps include indicative BAL ratings to illustrate the potential radiant heat impacts on areas within the proposed new subdivision development. It shows prospective lot purchasers indicative BAL ratings at the planning stage. The BAL for a new lot / building envelope is only ‘indicative’ as the new area may be impacted by more than one BAL contour and/or vegetation that can influence a future building’s BAL rating.

A site specific BAL assessment is required as part of the Building Permit approval process. This will determine what bushfire construction requirements of the Building Code of Australia (BCA) and Australian Standard AS3959 – 2009 Construction of Buildings in Bushfire-Prone Areas will be applied to the proposed building.

Please note that the City will not accept indicative BALs from BAL Contour Maps, Local Development Plans (LDPs), and Fire Management Plans (FMPs) at the Building Permit stage for the following reasons:

  • The potential allocation of an incorrect BAL (from a BAL Contour Map, LDP or FMP) could unnecessarily cost the home builder thousands of dollars. The land owner might over design their home constructing to a higher BAL. Or, they might build their home to a lower BAL, which increases the bushfire risks to their home
  • There can be significant time delays between the planning subdivision stage and building permit approval stage 
  • Indicative BALs do not have a defined expiry period. Site conditions change over time i.e. bushfire prone vegetation might have been cleared or revegetation has occurred
  • Inaccurate BALs could risk the lives of current and future occupants of residential buildings.

I am building a new house in a bushfire prone area, what approvals do I need?

There may be two parts to the approval process:

Planning Approval

Depending on the size of your lot, you may require Planning Approval prior to the submission of a Building Permit application. Please contact the City’s Statutory Planning Services for more information on 08 9411 3444 or at [email protected].

Building Approval

A Building Permit would be required for the construction of a new building or substantial additions and/or alterations to an existing residential building in a bushfire prone area.

What do I need to submit with my Building Permit application?

To apply for a Building Permit, your application must include the following:

  • Detailed plans and specifications for the proposed building work clearly demonstrating compliance with the Building Code of Australia and Australian Standard AS3959-2009 bushfire construction requirements.
  • A site specific BAL assessment report and BAL Certificate by a Bushfire Planning and Design (BPAD) accredited bushfire assessor.

Do the new laws mean I have to upgrade my existing house?

The bushfire reforms only apply to new buildings and major additions and/or alterations. They are not retrospective. As such, it is not mandatory for owners of existing homes within designated bushfire prone areas to upgrade their dwellings to comply with bushfire construction requirements.

What are the requirements for roof-mounted evaporative air-conditioning?

Embers from bushfires can enter the roof space of your home through unprotected gaps in your evaporative air conditioning unit and ignite the cooling pads. Once a fire starts in your air conditioner, it can spread rapidly to the rest of the building.

If you are considering the installation of a roof-mounted evaporative air conditioner, and your property is within a designated bushfire prone area, you will need to have your property assessed for its bushfire risk level. This will assist you in determining the appropriate level of protection your evaporative air conditioner will require. It should be noted that from 8 April 2016, new roof-mounted evaporative air coolers being installed on residential buildings within a bushfire prone area must be fitted with non-combustible covers.

Currently, it isn’t mandatory to upgrade an existing roof-mounted evaporative air conditioner. However, it is recommended that you consider retrofitting your air conditioning unit.

If you need more information about roof-mounter evaporative coolers, refer to the Department of Mines, Industry Regulation and Safety (formerly Building Commission) Roof-mounted Evaporative Coolers information sheet.

More information and contact

If you require more information on the Building Permit submission requirements, please contact the City’s Building Services on 08 9411 3444 or at [email protected].

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City of Cockburn
Whadjuk Boodja
9 Coleville Crescent,
Spearwood 6163

PO Box 1215, Bibra Lake DC,
Western Australia, 6965

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