Bushfire Attack Level Reports

A BAL (Bushfire Attack Level) is a means of measuring a building’s potential exposure to ember attack, radiant heat and direct flame contact, in a bushfire event. It is a basis for establishing the requirements for construction to improve protection of building elements from attack by bushfire.

The BAL takes into consideration a number of factors including the Fire Danger Index, the slope of land, types of surrounding vegetation and its proximity to any building.

There are six levels of bushfire attack under the Australian Standard 3959-2009, ranging from low to flame zone.

BAL – Low     There minor requirements that warrant specific construction requirements

BAL – 12.5     Ember Attack

BAL – 19     Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux between 12.5 and 19 kW mÇ

BAL – 29     Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux between 19 and 29 kW mÇ

BAL – 40     Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux with the increased likelihood of exposure to flames

BAL – FZ     Direct exposure to flames from fire front in addition to heat flux and ember attack

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