On Tue, 22 Jan 2013, Tony Langdon <vk3jed@gmail.com> wrote:
I can only comment on the system I know, which is the protection system used on a typical tanker (a lot smaller area to protect than a house!). For that space, the water usage is 150 litres/minute, and additional passive shielding is added, such as the vehicle body and reflective curtains for the windows, as well as individual protective clothing.
By "tanker" do you mean fire truck? If so then presumably the truck is designed to go into unsafe situations while a sensible person would cut down trees that are too close to their house and take other measures to reduce the risk.
I think it is feasible to build an active protection system, but it would be most effective (in both performance and cost) as part of an overall fire resistant house and garden design.
If you had a house made of solid relatively airtight concrete including a concrete roof with solid shutters then it doesn't seem that you would need any water protection system. If you had a house of a typical suburban design then it seems that no reasonable amount of water would save it unless you also have water inside the roof cavity to stop embers that get through gaps in the tiles. It doesn't seem like adding water will be guaranteed to save a house that wasn't already fairly safe without the water. Do bushfires get hot enough to ignite aluminium? A quick google suggests that aluminium ignites at about 2000C which combined with being a great reflector of light and even better for infra-red means that it's probably going to resist anything a bushfire can do from a distance. So aluminium shutters should do. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/