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  1. #1
    Dalmation90
    Firehouse.com Guest

    Post ISO Needed Fire Flow question...

    Ok K A (or anyone else )
    I have a question regarding the fire flow ISO will want to see us provide. The more I read the more confused I get!
    Off the ISO batch report, we have the following flows:
    5000gpm
    3500gpm
    3500gpm
    2500gpm
    1750gpm (2 hazards)
    1500gpm (3)
    1000gpm
    750gpm (5)
    500gpm (2 hazards -- thank you sprinklers!)

    If I'm interpreting everything right, our "Basic Fire Flow" is 1750gpm, the 5th highest on the list...and this determines how many/size of pumpers we need.
    Is that 1750 also what they want to see for maximum credit for water supply, or do they want to see the 5000? Or something else?


  2. #2
    cacfpd
    Firehouse.com Guest

    Post

    Very Interesting Question. Unfortunately I do not have the answer.
    It would stand to reason that you should not have to supply more water than you can possibly pump to the fire, but not all things make sense.
    Try contacting your ISO rep and ask him/her.
    Please post the answer so we all may learn a little.

    Stay Safe
    Dave

  3. #3
    Mike C
    Firehouse.com Guest

    Post

    """"Ok K A (or anyone else )
    I have a question regarding the fire flow ISO will want to see us provide. The more I read the more confused I get!
    Off the ISO batch report, we have the following flows:
    5000gpm
    3500gpm
    3500gpm
    2500gpm
    1750gpm (2 hazards)
    1500gpm (3)
    1000gpm
    750gpm (5)
    500gpm (2 hazards -- thank you sprinklers!)


    If I'm interpreting everything right, our "Basic Fire Flow" is 1750gpm, the 5th highest on the list..."""""

    Yes that is true off the batch List. However when they perform the survey they will no doubt find additional buildings that are not on the batch list. That could schew the fire flow.

    """"and this determines how many/size of pumpers we need."""

    Number of pumpers is determined by using the fire flow, in this case you need two.

    It is further defined by determing how often you respond out of district 10% is the magic number.

    Size of your area determines if more than 2 rigs are needed in this case. So if more than 50% of your homes or fire hydrant/water points are beyond 1.5 road miles from the fire station you'll need another station and engine.

    Plus rural water supply fill and relay pumpers add to the list. To atain the fire flow you need an engine at draft for a fill point, another to pump up a drive way where the tankers dump plus you'd need the two you are suppose to own plus maybe one or more for the size of the area covered.

    The fire flow also determines the number of firefighters and ladder or ladder service companies needed. If two engines is correct, if you are career you'd need 19 per call, If volunteer 55.

    """Is that 1750 also what they want to see for maximum credit for water supply, or do they want to see the 5000?""""

    Pumper are pumpers water supply is another issue.

    With the above list they will say you owe me 5000 your answer will be say 1750
    3500 " 1750
    3500 " 1750
    2500 " 1750
    1750 " 1750
    1750 " 1750
    1500 " 1500
    1500 " 1500
    1500 " 1500
    1000 " 1000
    750 " 750
    750 " 750
    750 " 750
    750 " 750
    750 " 750
    500 " 750
    500 " 750

    28,250 needed 20,750 gpm supplied = 73% or 25 ppoints for water.

    The limiting factor on the all fires will be fire apparatus pump capacity, water supply, hydrant flow, main limits, filters, or hydrant spacing. Which ever is lower. You also are responsible for the flows on the 3500 and 2500 gpm properties.

    The 5000 gpm fire, you are responsible for only 3500 gpm for full credit.

    Odds are you need to be running a lot more than two engines in the world of rural water supply and area covered.

    ""It would stand to reason that you should not have to supply more water than you can possibly pump to the fire, but not all things make sense. """"

    Why shouldn't you? It is your fire. What are you going to do about that little 5000 gpm event the day it burns? The insurance perspecive and sensible thinking would say you are in for a total loss.

    ISO is a very simple open book test. You get what you do or don't put into it.

  4. #4
    Dalmation90
    Firehouse.com Guest

    Cool

    Thanks Mike...
    Sometimes things don't make sense till you see them explained using a practical example.

    As for our "5000gpm" target...I doubt we'll ever have a significant fire in there short of a multiple point arson...no siginificant fire load -- it's the town's Junior High (1969/1993)...now if they had only sprung for sprinklers when it was expanded!

    Oh well, long way to go on this test, but things are looking better everyday

    Good luck out in TN land.
    Matt

  5. #5
    Drew Smith
    Firehouse.com Guest

    Post

    Item 501 of the FSRS (Fire Suppression Rating Schedule) states (last sentence) "The maximum BFF (basic fire flow) is 3500 GPM."

    Number of engine companies is determined by the BFF and listed in item 510. Maximum number of pumpers is three.

    As a side note, to get full credit for a pumper each pumper, including reserves, must have a pump (a real pump, not a 250 GPM PTO job), at least 1200 feet of hose and a full complement of loose equipment (not a whole lot of stuff). The formula for maximum pumper credit is Pump (1 point) X Hose (1 point) X loose equipment (654 points). If you have lets say a 1000 GPM pumper with 600 feet of 3 inch hose and all the required loose equipment you would get the following: 1 (pump) X 0.5 (hose) x 654 (equip.) = only 327 points, or half-credit! This is all in items 512 & 513.

    As for what your BFF is, you are correct is using the 5th flow (item 501 of the FSRS). Please note that Note 1 of item 340 on the FSRS shows a table for 1 & 2 family dwellings. Using this table, you could have different responses to house and other buildings and get the same credit.

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