Brian May wrote:
On 22 January 2013 16:57, Russell Coker <russell@coker.com.au <mailto:russell@coker.com.au>> wrote:
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.
Don't forgot that most houses burn down after the fire front has passed. If the house survives or not depends on if there is somebody around (risking their necks) to put out the small spot fires before they result in the house burning down.
Of course exceptions exist. Have heard that one house had its roof blown away, after which there was no saving it.
The other problematic area in the Marysville's fire was the gas cylinder venting valves pointing at other houses, and resulting damage, including broken windows which embers could enter.
I see a number of problems with the sprinkler system:
* Relying on mains water pressure or mains electricity is a big no no, there probably won't be any. That fire truck up the road will be using all the water pressure, and a tree will be down across the power lines. * If it is a petrol/diesel pump, somebody has to be able to start it. Plus it may not start when required. * The system would be very exposed as the main fire front passes. * If you start it before the fire front, you use up all your water before it is needed (after the front passes). ..............snip It may be that it is only practical ( physically achievable and cost effective) in certain situations. Which was why I was interested in the fundamental research. Consider an all weather-board house I visited in Belgrave ( in the middle of winter); which had state-forest with 30m gums and heavy undergrowth within 10m of the back of the house; I suspect the radiant flux from a crown-fire there would heat the air inside so rapidly it would almost explode !;
regards Rohan McLeod