On 22/01/2013 3:10 PM, Rohan McLeod wrote:
Assembled cognoscenti; it being the bush-fire season my thoughts turned to the practicability of protecting buildings , using external water-spray systems. My thoughts went something like this 1/ If one knows the air temperature, humidity, wind velocity, distance to, and composition and dryness of surrounding bush.
Some of those would be quite variable but might be possible.
2/ Can't one calculate the radiant heat in KW/m2 impacting on the building ?; and 3/ the likely duration in the event of a bush-fire ? 4/ Can't one then calculate the minimum spray flow in litres / sec and the total volume of water required ? 5/ Can't one then make an informed decision about, whether such a system is physically and financially practical in a particular situation?
That all seems reasonable. There was an item in a doco a while ago (I think it included the CSIRO) and they seemed to be interested in using water absorbent crystals (sodium polyacrylate I guess). Used less water and lasted longer. Their demo looked quite impressive. I have no idea how it would be "sprayed" on to a home in practise though. Cheers, Mike