The two spray positions can be seen at each end of the main roof ridge with their intersecting spray circles in grey
Our house in the No 72 group Shackleton Park is adjacent to a large natural reserve and I have always been conscious of the fire risk in summer. My two tanks hold about 6600L when full and providing the underground electricity supply holds good in a raging bushfire I should be able to use water for fire protection.
I considered various options which could be quickly engaged and which could be used in a precautionary way without involving a lot of human time holding a hose around the garden.
My eventual solution was to install two intermittent radial sprinklers, one at each end of the simple gabled roof. They have a 30m radius full circle spray overlapping in the centre of the ridge, thus effectively covering the whole roof, our 2 photovoltaic arrays
and, significantly, flooding the two long gutters, preventing embers from igniting the inevitable detritus. In doing so most of the sprayed water is thus returned to the tanks for respraying. They are turned on in 2 seconds in the carport area.
The sprays are independently connected to the water system and can as a precaution on a likely fire day be turned on for an hour or so before any fire to damp down the garden and nearby trees to reduce fire spread.
There are metal (plastic melts) gutter guards on top of all gutters to reduce detritus but some cleaning is occasionally necessary.
I guess no system is really perfect as there is always the possibility of water running out, although it switches automatically to the mains system when the tanks become exhausted. The mains of course is used by other houses in the viscinity and pressure may drop in a fire situation. Also the electricity may be cut off in the area but being underground in Shackleton Park is some comfort – but how much ?
There is also a knapsack spray placed in the garden room for spot fire use.