Today I extended our Bushfire/Wildfire External Water Spray System (EWSS) to the back decking. I finally found an elegant solution to wet down the decking by having sprays protrude up through the decking just under the side railing. this means that the spray are inconspicuous safe from damage. First tests show a good throw of water, I'm experimenting with both 360deg and 90deg sprays. The 90deg sprays throw water out at a low angle so they seem more reliable in high winds expected during a bushfire but the 360deg sprays are good on the far corner which has some ferns up against the decking.
The photo shows one of the 90deg sprays.