Bushfire Standards & Regulations

Regulations and Standards relating to Bushfire

Section G5 of the Building Code of Australia (BCA) regulates construction of buildings in bushfire prone areas and requires that various classes of building meet the requirements of Australian Standard AS3959 :2009. (It should be noted that State and Territory requirements do vary so it is advisable to check with the Authority having Jurisdiction).

AS3959: 2009 Construction of buildings in bushfire prone areas

This Standard and amendments provide a methodology allowing a Bushfire Attack Level (BAL) to be determined. It also provides guidance on the construction requirements for each BAL rating to ensure buildings are appropriately constructed and capable of resisting attack from burning embers, radiant heat, or flame contact.

The various bush fire attack levels BAL’s are outlined below.

• BAL - LOW. The risk is considered to be VERY LOW. There is insufficient risk to warrant any specific construction requirements but there is still some risk.
• BAL - 12.5. The risk is considered to be LOW. There is a risk of ember attack. The construction elements are expected to be exposed to a heat flux not greater than 12.5 kW/m2.
• BAL - 19. The risk is considered to be MODERATE. There is a risk of ember attack and burning debris ignited by wind borne embers and a likelihood of exposure to radiant heat. The construction elements are expected to be exposed to a heat flux not greater than 19 kW/m2.
• BAL - 29. The risk is considered to be HIGH. There is an increased risk of ember attack and burning debris ignited by windborne embers and a likelihood of exposure to an increased level of radiant heat. The construction elements are expected to be exposed to a heat flux not greater than 29 kW/m2.
• BAL - 40. The risk is considered to be VERY HIGH. There is a much increased risk of ember attack and burning debris ignited by windborne embers, a likelihood of exposure to a high level of radiant heat and some likelihood of direct exposure to flames from the fire front. The construction elements are expected to be exposed to a heat flux not greater than 40 kW/m2.
• BAL - FZ. The risk is considered to be EXTREME. There is an extremely high risk of ember attack and burning debris ignited by windborne embers, and a likelihood of exposure to an extreme level of radiant heat and direct exposure to flames from the fire front. The construction elements are expected to be exposed to a heat flux greater than 40 kW/m2.

A building element’s resistance of to bushfire attack is determined by testing in accordance with one of the following standards:

AS1530.8.1: 2007 Tests on elements of construction for buildings exposed to simulated bushfire attack - Radiant heat and small flaming sources. This Standard provides a repeatable test method for determining the performance of exterior building elements exposed to various intensities of radiant heat and simulated burning debris.

AS1530.8.2: 2007 Tests on elements of construction for buildings exposed to simulated bushfire attack - Large flaming sources. This Standard provides a repeatable test method for determining the performance of exterior building elements when exposed to direct flaming.