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Bega Valley Shire CouncilBega Valley Shire Council

BAL assessment guidelines

This guide will help you to determine the potential level of threat that your property may face during a bushfire so you know what level of compliance any new structure built on your property will need to meet.

It is informed by the Rural Fire Service Planning for Bushfire Protection 2019 guidelines and Australian Standards Construction Guidelines, known as AS3959-2018.

Any new building (including bushfire rebuilds) on land mapped as bushfire prone are required to comply with these guidelines. All new builds will need to complete a bushfire assessment report as part of the DA process. This can be a self-assessment document, which is available at Council office or at the RFS website.


What is a Bushfire Attack Level (BAL)?

This is a method of measuring the risk of a building’s potential exposure to ember attack, radiant heat and direct flame impact, using increments of radiant heat measured in kilowatts per m2. This is the basis for establishing the requirements for construction deemed necessary to provide protection at that level of risk.

Why do I need a BAL?

As part of your rebuild process you will need to confirm your BAL in a written report. You can do this yourself, using the steps below or engage an accredited Bush Fire Consultant. You can find one at www.fpaa.com.au. For more information on how to complete a BAL yourself visit https://www.rfs.nsw.gov.au/ or follow the steps, below.

How do I calculate my BAL?

Follow these five steps to assess your Bushfire Attack Level for your property.

  1. Find out what your Fire Danger Index (FDI) is. If you live within Bega Valley Shire, your property’s FDI is 100.
  2. Assess and understand the vegetation that surrounds your property. This could be forest, grasslands, woodland, shrub or mulga. The type of vegetation will increase or decrease your BAL.
  3. Know the distance between your house, building or structure (we’ll call these assets) and the vegetation on your property. This is known as the asset protection zone (APZ). The greater the distance between the vegetation and the asset, the lower the Bushfire Attack Level. You will need to measure this in metres.
  4. Determine the slope of your land. Bushfires tend to move rapidly uphill, so the greater the downhill slope between your asset and risk factors such as vegetation, the greater the BAL. You will need understand if you asset is up or downslope from the vegetation and measure this slope in degrees. For example flat land or 0-5o, 5-10o, 10-15o.
  5. Calculate your BAL. You can do this using the Guidelines for Single Dwelling Development Applications Kit at www.rfs.nsw.gov.au.

Once you have determined your BAL, you will know which level of the Australian Standard Construction Guidelines (AS3959-2018) will apply to your new build.

Things to remember when assessing your Bushfire Attack Level

  • The greater the hazard, for example vegetation such as forest, the greater the BAL.
  • The greater the downhill slope from your asset to the hazard, the greater the BAL.
  • The closer you are to the hazard, the greater the BAL.
  • The greater the APZ, the lower the BAL.
  • The more you can distance yourself from vegetation hazard, the lower the chance of ember, flame or radiant heat attack. This will reduce the required construction level

Conversely, if you are limited in the ability to provide an APZ, then the BAL will increase.

What do the BAL Levels mean?

There are six Bushfire Attack Levels. BAL-low is the lowest bushfire risk and BAL-FZ (Flame zone) is the highest risk. The closer your asset is to the fire, the higher your BAL. If you can decrease your BAL you will likely decrease your construction costs.

BAL Levels

BAL Level Description of risk
BAL - LOW Lowest risk from a potential fire.
BAL - 12.5 Risk is parily from potential embers during a fire.
BAL - 19 Moderate risk, particularly from embers and burning debris.
BAL - 29 High risk, particularly from embers, debris and heat.
BAL - 40 Very high risk. Likely to be impacted by embers, debris, heat and potentially flames.
BAL - FZ Extreme risk. Directly exposed to the flames of a potential fire front.

Image of BAL levels

 

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