in fire fighting, a device for generating and directing a stream of water, foam, powder, or other fire-extinguishing substance. The simplest type of nozzle is a tube with a terminal attachment that adjusts the stream. Fire-hose nozzles can generate narrow or dispersed streams, and they make it possible to stop the flow without shutting off the supply. A foam stream is obtained from a 1–6 percent solution of foaming agents in water; the solution is dispersed by a nozzle attachment in a jacket, in which drops are mixed with air ejected by the force of the stream. The output of fire-hose nozzles varies from 1 to 200 kg of fire-extinguishing substance per sec.
A distinction is made between hand nozzles (with outputs less than 13 kg/sec) and turret nozzles. Turret nozzles may be fixed, for example, attached to the roof of a vehicle, the deck of a cutter, or an elevating platform, or they may be transported by some vehicle or by hand. Hand-held nozzles are used on fire engines, motor-operated pumps, and hose stations inside buildings. Fire-hose nozzles are attached to hose lines by means of quick-attachment heads.