Bushfire Areas

The AS3959:2009 Bushfire standard declares some timbers as inherently fire retardant. These timbers can be used in all BAL levels up to BAL29 without any compliance requirements.

The list is as follows:

Standard Trade Name Botanical Name
Ash, Silvertop Eucalyptus Sieberi
Blackbutt Eucalyptus Pilularis
Gum, Red, River Eucalyptus Camaldulensis
Gum, Spotted Corymbia Maculata
  Corymbia Henryi
  Corymbia Citriodora
Ironbark, Red Eucalyptus Sideroxylon
Kwila (Merbau) Intsia Bijuga
Turpentine Syncarpia Glomulifera

There are many other timber types permitted in sections 5 and 6 of each BAL level section of the standard and are references in Appendix E - most are of the Eucalyptus family. They basically fall into two groups:

  • 650kg per /m2
  • 750kg per /m2

To identify these timbers, you will need to reference the The AS3959:2009 Bushfire standard, or you could call us. These timbers can be treated with a fire retardant if desired. They can also be treated with a fire retardant and tested for compliance should you need to use a species that doesn't comply for your intended use.

In summary of the above. Any timber that is on the list of inherently fire retardant timbers, or has been treated with a fire retardant and tested to meet compliance, can be used in all instances up to BAL29. untreated timbers listed under appendix E can be used as permitted in sections 5 and 6 of each BAL level standard.

Fire Defender have compliant test reports for several timber types. Call us to see if our product can provide your solution.

The AS3959:2009 bushfire standard comprises two components for timber to be full exposure compliant and meet fire retardant compliance.

  1. ASTM D2898 which is accelerated weathering.
  2. AS3837 which determines the fire resistance level. 

AS3837 - Cone Calorimeter:

The standard AS3837 test also known as the Cone Calorimeter test, has been around for some time and used in the commercial building sector;  usually a group rating is the result reported. For bushfire, the same test method and equipment is used, but the indices required for the bushfire test report are different, therefore a standard AS3837 test is not acceptable. 

The criteria to be met and the results that must appear on valid test reports are:
  1. The maximum heat release rate shall be no greater than 100 kW/m2.
  2. The average heat release rate for 10mins following ignition shall be no greater than 60 kW/m2 when the material is exposed to an irradiance level of 25 kW/m2.

If the product only has the AS3837 component, the product can be used in what is deemed to be “unexposed areas”. An unexposed area is any surface area inside 30deg’s of any overhang.

ASTM D2898 Weathering:

Where accelerated weathering is required before AS3837 testing i.e. when externally coated fire retarded timber is to be fully exposed to weather, it shall be subject to the ASTM D2898 Method B weathering process, with water flow rates modified to be the sames as ASTM D2898 method A prior to the AS3837 con calorimeter fire test.

If it has both components, it can be used in full weather exposed areas however, timber fire retardant treatments can only be used up to BAL 29 bushfire zoning.