Process of Pumping Water Out of a Fire Truck
I know that not everyone understands the fire service and how hard of a job it is, but I think after I give a crash course in pumping you can understand how hard it is. There is few important things in this which are putting the truck in pump gear, pumping water, and having a constant water supply.
First thing when the engineer pulls on scene of a fire he must put his truck in pump gear. All trucks pump in a different gear, but they have a sticker that indicates what gear to use. To put the truck in pump gear the engineer must shift his truck to neutral, pull the emergency/park brake, and throw his PTO lever down one slot and the when the light turns green put in down in the final slot.
All fire truck ...view middle of the document...
The next valve is the "Tank Fill/Recirculation" valve. What this valve does is cycle the water back and forth so it will not burn the pump up. Next you pull whatever valve you want water to come from. On a fire attack nine times out of ten it will be your "Number 1 Cross Lay" this is your main hose line. After you pull your valve you have a throttle on the side that is either computer based or the old fashion twist knob. You have a main gauge that shows you discharge pressure and the most common pressures you want to throttle up to is 130 to 150 PSI. Some older trucks have a discharge relief valve, which all new trucks its built in to work automatically, but the older ones what this does is when you are flowing water and it gets shut off very quickly it relieves the water to a special line so it won't "water hammer" the pump and mess it up.
You can fight any fire the way I just explained if it's reachable with your cross lays. Our first out pumper carries 1000 gallons of water this can last you a good bit of time, but if you have a fully engulfed structure you are going to need a constant supply to that truck. If your fortunate enough to have hydrants in the area you can drop a supply line and "tag" the hydrant. Around Mullens we can rely on getting 150 PSI from a hydrant which is great. If your not so lucky and have to get additional tankers or whatever is available they will run a supply line to your truck and have to pump the same amount in as you are out.
I know this was a very fast and brief explanation, but I'm sure everyone thinks when you have a fire its simple to get water. I hope this was a good explanation of how getting the "wet stuff on the red stuff" works.