There are 6 recognized levels of ratings; from BAL (low), BAL 12.5, BAL 19, BAL 29, and Bal 40 to BAL FZ (highest). The relevant Australian standard AS3959 provides the requirements built in these varied bushfire risk areas.

Bushfire Attack Level for Ironbark:

Red Ironbark (BAL) 12.5, 19 & 29
Grey Ironbark (BAL) 19

Durability is defined as the resistance of a timber species to decay, or to insect attack. A scale of low to high has been adapted for above ground durability.

Ironbark has a durability level of 1

4 = low (0-7 years)
3 = Moderate (7-15 years)
2= Reasonably High (15-40 years)
1 = high (More than 40 years)

Grey Ironbark
1106kg/m3

Red Ironbark
1050kg/m3