By BILL NEMICK
Have you ever been on the end of a hoseline when the water pressure was either too high or too low for the nozzle, resulting in a poor fire stream? Or, have you ever wanted to change the tip size or gallonage setting on the nozzle but decided not to because it was too difficult to communicate accurately with the pump operator? I have, and it can be quite frustrating. A solution to this problem exists that many firefighters discount because of a lack of a thorough understanding or a second- or third-hand story they once heard. This story involves a mysterious firefighter in another department (of course!) that had a catastrophic problem with this solution. This solution is a constant-pressure, variable-gallonage combination nozzle, better known as the automatic nozzle. I believe the automatic nozzle is a far better choice than the standard constant gallonage or adjustable gallonage nozzles.
First, let's review the two other combination nozzle types: the "constant-gallonage" nozzle and the "adjustable-gallonage" nozzle. The constant gallonage nozzle is the simplest of these nozzles because it has a fixed orifice that is rated for a predetermined gallons per minute (gpm) at a standard nozzle pressure. This means that its rated pounds per square inch (psi) will produce a predetermined volume of water. This constant-gallonage nozzle has no adjustments on it that affect the volume of water being discharged. The pump operator is in complete control of this volume and only needs to know the rated nozzle pressure and the pressure loss in the hoseline to correctly supply the nozzle. The volume control for a constant-gallonage nozzle is similar in principle to that of a fixed orifice smooth bore nozzle.
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