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  1. #21
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    A couple of things that will make it a little easier.

    1. Figure out all of your preconnects and simply commit the needed discharge pressure to memory.

    2. Standardize all preconnects on all apparatus so it will be the same.

    3. Figure out your GPM from your various smoothbore tip sizes and simply commit it to memory.

    If you do those three things, any calculations on a fireground will be very easy. If you figure out the friction loss ahead of time and commit it to memory, then it will cut down on the amount of calculating you have to do on the fireground.

    A cheat sheet on your apparatus (to be used for checking yourself) can be very helpful too and easy to make.


  2. #22
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    Quote Originally Posted by ChiefSquirrel View Post
    A couple of things that will make it a little easier.

    1. Figure out all of your preconnects and simply commit the needed discharge pressure to memory.

    2. Standardize all preconnects on all apparatus so it will be the same.

    3. Figure out your GPM from your various smoothbore tip sizes and simply commit it to memory.

    If you do those three things, any calculations on a fireground will be very easy. If you figure out the friction loss ahead of time and commit it to memory, then it will cut down on the amount of calculating you have to do on the fireground.

    A cheat sheet on your apparatus (to be used for checking yourself) can be very helpful too and easy to make.
    Thanks Chief,
    I have pretty much already done all of this for the class. I also have a cheat card that covers our normal and preconnect situations. I am looking to someones worksheet to force more thinking and confidence should the need arise that the lay changes.
    Jason Brooks
    IAFF Local 2388
    IACOJ

  3. #23
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    Pump operations is one of the things I teach the most. I find that nothing works as well as simply doing it over and over and over.......

    Create some scenarios and work through them - the confidence will come as the repetition builds your skills.

    After any calls you go on, try to put yourself in the pump operator's position and calculate what he had to calculate and then compare notes with him. This is a great way to build your skills, make sure his are sharp and learn based on a real situation.

  4. #24
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    I always go with this method, if the crew chief wants more he will ask if not than the 150psi i am giving him has either been good enough or he is making due with it and not needing anymore

  5. #25
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    Most engines run with preconnected lines which comes with set pressures based on the nozzle type, length of hose and expected gpm. So the solution is memorize those numbers.
    For UDC loads or dead loads where the length varies... know the friction loss per 100 ft and add it to the amount over the number you memorized from the preconnected lengths.
    Friction loss changes based on the gpm you are trying to flow. Know what your fire department wants to flow and base it on that. Not all fire departments use the same flows.
    If you know your nozzles pressures and you know your friction loss number then you can make your own cheat sheet.
    Here is an example: We have 200' x 1.75" with 150gpm fog tip preconnected line, my pump discharge pressure will be 170psi. That gives me 100 psi at the tip and 35 psi friction loss per 100 feet.
    If I were to put a smooth bore on the end I would subtract 50 psi because of the nozzle pressure difference so it would be 125 PDP
    Now you can figure the same for the 2.5 lines or whatever your department runs.

    Not knowing hydraulics is a problem but it only small portion of the problem.
    The biggest route of the problem in the fire service in general is not understanding the pump operators position or engineers position. Trouble shooting the pump has become a lost art with the implementation of pressure governors. Too often people think that the idle button is the answer to every problem without knowing what is happening to cause the problem. This is a very dangerous move for the people on the nozzle that lose pressure in a hostile environment. Another problem is understanding relay pumping. Volume and pressure concepts, pressure loses, hyrant pressures and volumes available need to be understood. You may have a 1250 pump but is the water system where you work going to be deliver that to you? What is it going to take to get that volume? How many gpm's are you going to need to put out the fire you are coming up to? What is your size up as a pump operator? Do you have enough water availlable if not where are you going to get it from? And what method can it be delivered?
    Sorry if I got off on a tangent but I have been seeing too many people becoming engineers that are not ready.
    IACOJ

  6. #26
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    We run 300' preconnected and 200' preconnected 1 3/4" lines with fog nozzles. We did flow tests and a bunch of scenarios based on our typical operations and found that we wanted the 200' lines pumped at 130 psi and the 300' lines pumped at 150 psi.

    Then we went to the guy that decals our trucks and had him make little stickers that go on the discharge gauges, about the size of a quarter, and stuck'em on there. Obviously this doesn't account for all of the variables, but if the pump operator sets them at the "sticker" to start we are in the ball park.

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