A highly debatable topic concerns whether the combination nozzle will push fire. Indeed, while it might be possible to push fire in the fog setting due to the massive air movement it develops, generally neither the straight-stream nor the smooth-bore pushed fire any more or less than the other, provided that the flow rate is adequate for the amount of fire. Neither the smooth-bore nor the combination nozzle in a straight stream setting has any great effect on air movement. This is not to say that neither nozzle will push the products of combustion when an overabundance of steam is created. Remember, for every gallon of water required to extinguish the fire, about 200 cubic feet of steam is produced. In situations where stream production is more of a concern, such as when victims are inside the structure, using short, intermittent bursts will minimize this effect.

Here’s a simple test to demonstrate this phenomenon. Set a garden-hose nozzle to the straight setting and shoot the stream through the flame of a small campfire or bonfire. The stream will travel through the flames and emerge on the other side with virtually no impact on the flame. Then change the stream to a fog pattern or move the plunger nozzle in a circular pattern. You will begin to see the flames dance in response to the air movement. The same test can be duplicated using a pump-can or pressurized extinguisher with its solid-stream.

Low-pressure nozzles will perform equal to a smooth-bore tip when used in the straight-stream setting at the same flow and nozzle pressure. But while the smooth-bore nozzle is not a bad nozzle, in the majority of fires the combination nozzle will be used in a straight stream setting in the same way as the smooth-bore dlla138s191 nozzle. This leads to an important question, why, if both nozzles provide an equally effective straight-stream pattern, would firefighters not want to use the nozzle that offers the greatest versatility? This answer is obvious, to produce a lower-pressure combination nozzle that would still offer versatility but operate at pressures more consistent with the smooth-bore streams.