The excitement that comes with a new apparatus delivery is probably second only to making a nearly impossible stop or rescuing a victim at a structure fire. After months of anticipation, you can't help but drool over flawless red paint, more flashing lights than an Academy Awards' red carpet, and diamond plating so shiny you could shave in its reflection. Add in the fresh stock of equipment gracing each compartment space, and you have a recipe for a near-syncopal episode. These feelings were ever so real to me in the last couple of weeks when my station received a tower ladder fresh off a Wisconsin factory floor.
In putting the truck through its paces, flow testing the master-stream nozzles was of particular importance. The decision was made to finish off the waterway with one automatic fog nozzle and one stacked tip smooth bore nozzle. Once water was flowing, it was quickly evident that simplicity of the smooth-bore would be contrasted by the multitude of possibilities that comes with a master-stream automatic nozzle. Our particular fog nozzle gives firefighters the option to select a nozzle pressure ranging between 70-120 psi. The flow-meter showed upwards of 1500 GPM with the fog nozzle set at 100 psi receiving about 190 psi at the base of the truck. Simple logic would say that a higher pressure would flow more water, and being firemen, we obviously wanted to test the limits from the get-go. The dial was cranked to 120 psi nozzle pressure! Our total GPM instantly dropped by almost 300 GPM. With everything else being equal, this is expected from an automatic fog nozzle. GPM is often sacrificed for the appearance of an "effective stream."
Pumping into the truck at a higher pressure was required to get flows back in the range of 1500 GPM with the 120 psi nozzle setting. This nearly exhausted the capabilities of our engine with a pump rated around 1500 GPM. Again, we are firemen, and we felt that the limits were not properly tested; a neighboring station had recently taken delivery of an engine with a pump rated at 2000 GPM, and their services were requested. It was not until almost 240 pounds of pressure were being sent to the base of the truck that GPMs even reached 1600 GPM. It certainly is not worth partially-activating pressure relief valves on the waterway, taking supply lines to their maximum capacity, and changing out an entire engine just to achieve a marginally better flow. The decision was made to leave the nozzle permanently set at 100 psi, pending abnormal circumstances.
The moral of the story is that sometimes less is more.
Firefighters often get caught up in the mindset that everything must be overwhelmed by strength, power, and the "maximum setting." This is why we see guys pulling out a 36" halligan when a shove knife will do. This is why 100 psi fog nozzles are the only option on engines across the country. This is why attempts are made to use a 3" hose as a hand-line. This is why there are apparatus chauffeurs who still grossly over-pump discharge pressures.
Efficiency and effectiveness should be given equal consideration in the decision making process. This type of critical thinking is what separates the "professional" from the amateur. Had we sided with ego and decided to leave the nozzle on its maximum setting, our master stream operations would have undoubtably suffered. There are certainly situations where going all out is necessary; there should just be a purpose behind doing so. Next time you have the urge to make an ego-driven decision on the fire ground consider, "can I get more by using less?"