Deluge gun
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The deluge gun, "master stream", "deck gun", or "fire monitor" is a high-capacity nozzle used by firefighters. The guns are normally mounted on top of fire engines and are capable of pumping up to, and sometimes over, 2000 gallons per minute (126 litres per second).
Deluge guns are also available in portable designs so a firefighter can set up the gun to apply water to a blaze then leave it in place so the firefighter is free for other tasks. Facilities with highly flammable material such as oil refineries may have permanently installed deluge guns for use in the event of a fire.