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Bushfire testing


In Australia, there are rigorous standards for the construction of buildings in bushfire-prone areas. Buildings in nominated bushfire zones must be capable of resisting the impact of a bushfire without active firefighting intervention.

The fire performance of construction details, materials and systems is determined in accordance with Australian Standard AS 3959 Construction of buildings in bushfire-prone areas.

Testing accreditations

BRANZ is accredited by International Accreditation New Zealand (IANZ) for testing the fire performance of products, materials and systems using a variety of test methods.

In Australia, the results from the following tests can be used to determine the fire performance which is required in accordance with AS 3959:

  • AS/NZS 3837 Method of test for heat and smoke release rates for materials and products using an oxygen consumption calorimeter
  • AS 1530.8.1 Methods for fire tests on building materials, components and structures. Part 8.1: Tests on elements of construction for buildings exposed to simulated bushfire attack – Radiant heat and small flaming sources
  • AS 1530.8.2 Methods for fire tests on building materials, components and structures. Part 8.2: Tests on elements of construction for buildings exposed to simulated bushfire attack – Large flaming sources.

Bushfire attack levels 12.5 to 40

AS 1530.8.1 is used to simulate a passing bushfire for Bushfire Attack Levels (BAL) between 12.5 and 40.

This test involves mounting a steel panel over the opening of a fire resistance furnace to generate a specific radiant exposure regime onto the specimen. 

Alternatively, compliance with BAL ratings from 12.5 to 40 (including Flame Zone (FZ)) can be demonstrated using conventional fire resistance testing in accordance with AS 3959.

BAL flame zone

AS 1530.8.2 is used to simulate direct flame exposure for BAL Flame Zone (FZ).

For this test, the specimen is mounted into a fire resistance furnace test frame as it would for fire resistance testing.

Alternatively, compliance with BAL FZ can be demonstrated using conventional fire resistance testing in accordance with AS 3959.

Bushfire-resisting timber

AS 3959 defines Bushfire-resisting timber as withstanding exposure up to a BAL 29 condition.

This can be determined from testing small samples to AS/NZS 3837.

To pass this test, many timbers have their ignitability modified with fire retardant by either impregnation or surface coatings. For these, BRANZ also has the facilities to carry out the required accelerated weathering cycle ASTM D 2898 Method B, with the water flow rate modified to be the same as that within ASTM D 2989 Method A.