When building in areas considered to be a bushfire risk architects and builders must consider design and the choice of materials.
While preventative measures such as the installation of fire sprinklers, block out shutters or regulating set backs are well understood, there is still confusion about what timbers may, or may not, also offer protection from bushfires.
Under AS 3959, all timber used externally on buildings in areas designated to be a fire risk, must be resistant to ignition. In December 2001, Building Control Commission Practice Note No. 46 was issued to address concerns about the lack of commercially available chemical fire retardants required by the previous regulations. BCC Practice Note 46 now identifies seven hardwood timber species that have been tested and are deemed to satisfy the fire resistant requirements in AS 3959, provided they have a minimum thickness greater than 18mm. All new buildings around Australia must be compliant with these regulations.
Silvertop Ash (Eucalyptus Sieberi), one of those seven, is native to eastern Victoria, southern NSW and parts of northern Tasmania. While Silvertop is present in stands of old growth forest it is more commonly found as a re-growth timber in the native Victorian forests of Gippsland. Silvertop Ash is typically a light blonde to honey brown coloured timber.
Silvertop Ash products may not be readily available locally but Victorian company Radial Timber Sales specialises in the production of hardwood decking, external cladding and screen boards from Silvertop Ash.
Source: Building Products News.
