In Australia, bushfires are a part of life but not one that should be taken lightly. While building with steel doesn’t make your structure “fire proof” it can most definitely increase the fire resistance of your home or business premises.
The National Association of Steel-Framed Housing Inc. (NASH) recognises three main ways in which bushfires may present a risk to houses:
- burning embers
- heat radiation
- flame contact
Why build with steel in bushfire-prone areas?
One of the biggest concerns in the event of a bushfire threatening homes as noted above, is the potential for burning embers to gain access to roof and cavity areas, igniting timber battens or structural members. In this scenario particularly, steel is the better option. This is because timber only requires a heat source of approximately 280°C to ignite. After ignition, and with the right fuel, fire in timber structures can take hold quickly. Steel, on the other hand, is non-combustible and will not lose any of its strength until temperatures reach around 400°- 500°C. For these same factors, steel is also more preferable for resistance to heat-radiation.
The third mode of fire threat to homes is noted by NASH as “flame contact”. If you’re building in a bushfire-prone area, choosing a steel framing system as part of your overall selection of fire-resistant building materials is strongly recommended. While contact with the flames of a bushfire is a catastrophic scenario, doing so can minimise or delay the degree of damage to your structure – affording precious moments to evacuate people and precious belongings.
In fact, a building requirement of structures built in bushfire-prone areas is that structures must be designed and built to reduce the risk of igniting in the case of a bushfire. To add to this, not only is it better to build with steel frames in bushfire prone areas for the above reasons especially, but it’s actually cheaper than traditional timber framing.
Building Standards for Bushfire-Prone Areas
The National Construction Code has suggested solutions to support these requirements, including two Standards – both of which can be applied to construction in all Australian states and territories:
- The NASH Standard Steel framed construction in bushfire areas, and;
- AS 3959 Construction of buildings in bushfire-prone areas
The Standards make recommendations for different levels of Bushfire Attack Levels (referred to as BALs). Some of the recommendations include:
- The use of cold-formed light gauge steel frames and trusses
- The use of non-combustible cladding (also including brick and masonry
- applications, fibre cement, etc.)
- The combined use of steel roof sheeting and foil-backed insulation blanket
- Additional ember protection where required (depending on the BAL)
- Outlining circumstances in which additional protection is not required
Standards Recognise Steel Framing Systems as Ideal
Interestingly, the Standards recognise that normal steel framed building practices can be safely applied in bushfire-prone areas. This fact alone attests to the incredible ability of steel framing systems to stand against the potential destruction of bushfires.
Are you building in a bushfire-prone area? At AusSteel, we are well-versed in designing and manufacturing framing systems to resist bushfire damage. We’ve got you covered. We have facilities based in QLD (Crestmead, Brisbane) and NSW (Newcastle and Goulburn). Wherever the location of your upcoming project may be, we can help. Let’s chat today.
Reference: ‘NASH Bushfire Standard Provides Economical Solutions for Bushfire Areas’, accessed 19/10/2023, National Association of Steel-Framed Housing Inc. https://nash.asn.au/why-choose-steel/safety-and-security/bushfires/
