With bushfire season approaching Australia, one of the many aspects that should be considered in building, construction and architectural projects is the land’s Bushfire Attack Level.
Bushfire Attack Level (also known as BAL) determines the appropriate building materials that can be used on the applied land development. In carefully determining a bushfire prone land’s level, it can help protect families, homes and even save lives.
According to the NSW Rural Fire Service, there are six bushfire attack levels currently in the system. Each BAL is set out to comply with Australian Standard: 3959 Construction of buildings in bushfire-prone area 2009 (AS3959)
Bushfire Attack Level (BAL) construction requirements:
BAL-LOW: Minimal attack from radiant heat and flame, although some attack by burning debris is possible. There is insufficient threat to warrant fire resistant products, however basic property preparation is still advised.
BAL-12.5: Low levels of radiant heat but attack by burning debris is significant. The radiant heat is less likely to threaten building elements. However fire and debris protection products are warranted (Level 1 construction standards).
BAL-29: Significant attack from burning debris, radiant heat levels can threaten buildings and some flame contact is possible. Specific fire protection construction products are warranted.
BAL-40: Extreme radiant heat, increased attack from burning debris and potential flame contact, which can all threaten building integrity. All buildings must be designed and constructed with specific fire protection materials that can withstand extreme radiant heat and potential flame contact.
Flame Zone: Radiant heat levels will exceed 40kW/m2 and will significantly threaten building integrity and residential safety. Flame Zone areas exceed the scope of the Building Code of Australia. Applicants are recommended to take protection measures in order to make bushfire prone lands safer and comply with BAL criteria. Protection measures that would be required include drenching systems and radiant heat barriers.
In order to determine the BAL of the land, an Asset Protection Zones (APZ) and construction standards methodology needs to be taken. This site assessment methodology is outlined in the Planning for Bush Fire Protection 2006 (PBP). Alternative assessment tools, such as APZ calculator and Bush Fire Attack Assessor, are also available on the Rural Fire Service website.
For more information on Bushfire Attack Level assessments on bushfire prone lands, visit your state’s Rural Fire Service website.