BAL-12.5
Lowest assessed Bushfire Attack Level under AS 3959, corresponding to a radiant heat flux of up to 12.5 kW/m squared and limited ember attack risk.
Bushfire Attack Level 12.5 is the lowest of the five rated BAL levels in AS 3959 (Construction of buildings in bushfire-prone areas). It applies to sites where the predicted radiant heat flux is up to 12.5 kW/m squared, with the principal hazard being ember attack rather than direct flame. Construction requirements include ember-proof gaps, screened weep holes, and bushfire-resisting timber species or non-combustible materials in some elements. BAL is determined by site assessment under Method 1 or Method 2 of AS 3959, considering vegetation classification, slope, and separation. For buyers, BAL-12.5 still mandates compliance details that ordinary construction does not, including specific decking species, mesh openings, and seal types. Always verify the BAL on the building permit before ordering materials.
Values and references on this page are indicative and drawn from common industry sources. Always verify the current AS/NZS standard, manufacturer data sheet or NIAA policy publication before relying on figures for design, specification or compliance work.
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