With all the new technology out there, there are numerous hydraulics equation apps available on smartphones and calculators. But what happens if you forget your phone or calculator, or if it runs out of batteries? The best calculator you have is the one that goes with you everywhere 24/7/365 — your brain.
There is no doubt having a pencil and paper or dry-erase board on the truck helps. Some hydraulics equations can become somewhat complicated. Whether you use rule of hand/thumb, percentage equations, K factors or any other method, we need to continue to practice doing the math in our head on a regular basis.
Like anything else, practice makes perfect. Plus, we are getting paid to do it as part of our profession. The public depends on us to perform.
These rare hose lays are far and few between (at least where I am from). Regardless, we need to be prepared. As with any emergency scene, time is of the essence. Therefore, we need to think on the fly, calculate and adapt at a moment's notice.
Since the fire ground is a dynamic, ever-changing environment, equipment malfunctions and breakdowns occur. We may need to come up with creative ways of accomplishing a unique task never presented to us before. We need to think outside the box.
So, if we take the driver who only knows the pressures of their pre-existing, preconnected hand-lines and master stream devices, and does not know the theory or how to do a hydraulic equation using his head, what happens when a hose bursts or a nozzle malfunctions?
As we all know in the fire service, we usually replace a burst section of hose with two sections. This changes the hydraulic equation/pump pressure. If a nozzle malfunctions, we need to replace it with a spare nozzle. The spare nozzle may have a different GPM and nozzle pressure. This once again changes the equation/pump pressure. Also, if different diameter lines are integrated to reach greater distances or to supply a master stream device, as in a fill-in lay, the same occurs.
The other benefit is that as equipment changes and advances take place, all we need to do is plug in the new hose conversions, nozzle GPM/friction loss and nozzle pressures into the equation. We can always adapt to whatever change occurs.
It is imperative that every engineer knows all the nozzles on his truck, preconnected, spares and master stream device. Pumping incorrect pressures is dangerous. Too little pressure results in insufficient GPMs being delivered, and personnel on the line will be pushed back by fire. Too much pressure means the hose line can become unmanageable and difficult to handle, and result in serious injury.
We need to stick to the basics and understand the theory behind fire hydraulics, and not become too dependent on technology. Once it is learned, it is hard to forget. To keep our minds fresh at our department, we would practice equations as a group at least once a month.
Be sure to also update your nozzle charts and memorize them. Remember, the people we serve deserve to know that you're able to perform at a moment's notice when needed.
This article was written for & published by MultiBriefs.