New Scientist: Fighting fire with a steam machine

19:00 03 March 04
"A chance discovery has transformed an engine intended for speedboats into a powerful firefighting tool that douses flames with jets of water mist.
When used for boats, the engine works by injecting steam through a rear-facing, ring-shaped nozzle into a cylindrical chamber. As the steam emerges at three times the speed of sound, it rapidly condenses, generating a shock wave that pulls in water through an intake and expels it from the rear, generating thrust (New Scientist, 29 January 2003)." Cool. I remember in firefighting school that we learned to use a mist to beat back certain kinds of fires and protect firefighters. This would be a really quick way to get a layer of AFFF (aqueous film-forming foam) on a class B fire.