The roof of a structure is often forgotten when designing for fire protection from an external source. Up until recently this was the case in Australia for houses built in locations that may be subject to extreme bushfire conditions.

    It seems incredible that so much effort and cost is put in to designing and building the external walls of houses in such zones and yet a roof is ignored. Typically the flame front of  a  bush fire will pass in a matter of  2 or  3 minutes but the ferocity and  temperatures of these fronts can reach in excess of 1200°C.

    It is quite common in Australia for house owners to retreat inside their homes until the front passes and then emerge to put out any fires that are burning whether they be in the surrounding bush or the house itself. What has been ignored up until now is the effect that these extreme temperatures will have on the combustible roof and wall framing in the aftermath of the fire front.

    Tests have shown that even after the fire front has passed, combustibles like timber framing contain residual heat and indeed the heat can continue to grow. The result can be that even after some considerable time, ignition can occur within roof spaces and wall cavities and the innocent house owner may well have moved on from their own property to assist neighbours only to return and find their home burnt down or severely damaged. An even worse scenario is that the house owners stay inside their homes, (and may even go to bed) thinking that they are safe, only to find themselves in trapped within a burning inferno.

    The development of a compliant roof systems, which was jointly funded by Forest and Wood Products Australia Limited, BlueScope Steel Limited and Promat Australia Pty Ltd, is a cooperative approach to overcome the challenges associated with the design of construction systems that meet the requirements of the most extreme bushfire attack level under the new Standard. A Promat solution for the main roof using PROMATECT® 40 Mineral Bound Magnesia board has been successfully tested at a NATA approved facility, Exova (Warrington Fire Research) and is now available. Further work is required for solutions for eves linings, valleys, box gutters and fascia which are expected to be completed within a matter of weeks.

For further information please contact
Promat Australia on 1800 01 13 76 (from within Australia)
www.promat-ap.com

Full article by Building Commission Media Release are available for download as follows:

• FZ roof BC Media Release