Quote:
Originally Posted by 4 for Boating
Honest question here as I'm trying to educate myself on the engineering of the Fire Trucks.
So non-island waterfront fires, can the truck pull from the lake for supply?
I realize they can pull from lakes, ponds and even swimming pools if need be to "fill" the tanks but are the trucks designed to pull and also pressurize to address a fire in real time? (Like a fire boat does?)
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Yes they can. Fire pumpers are tested when delivered new, and regularly afterward, to be sure they meet the rated capacity of the pump. The test to draft from a lake or water source requires that it be at least 4 feet deep, clear water, and the lift should be 10 feet from the water surface to the center of the intake on the pump.
That would represent a real test. Obviously, testing from a hydrant defeats the purpose because the water coming into the truck is already pressurized.
In a major fire situation a pumper at a hydrant feeding a pumper or ladder pipe at the fire needs to watch the intake pressure because you can exceed the capacity of the hydrant and water main to supply the volume you are using. That is one of the reasons the driver always says with the truck.
Here is a a trick: When using a hydrant and the intakes at the pump panel on the truck if you are close to exceeding the capacity of the water supply it helps if the operator keeps his leg against the hose line. That way if you are distracted and don't notice on the gauges that you are going into a vacuum situation you will feel the line go soft. OK..........TMI.
At most waterfront houses there is not sufficient clearance to get to the lake. You also have to worry about septic systems, overhead wires Etc before you start driving through some yard you are not familiar with. It would have to be a pretty large yard because you couldn't be too close to the building that was on fire.