# Does it exist...??

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• 04-06-2008, 07:37 PM
cchiasson17
Does it exist...??
I know this might be strange but i'm currently looking for ''formulas'' to size up how much water we will need on this burning building. i dont know if anyone has something that is working for them but i'm looking forward to see the replies i get.

Thanks
• 04-06-2008, 08:01 PM
DugdogFiredog
Quote:

Originally Posted by cchiasson17
I know this might be strange but i'm currently looking for ''formulas'' to size up how much water we will need on this burning building. i dont know if anyone has something that is working for them but i'm looking forward to see the replies i get.

Thanks

This may help. I recommend reading the entire article, but I believe the formula you are looking for is about 3/4 of the way down the page.

http://www.fireengineering.com/displ...ompson-Diagram
• 04-07-2008, 08:25 AM
mdtaylor
Almost every Fire Service Hydraulics book has the formulas and rules of thumb for required fire flows.

Three methods commonly used (when used) are the Iowa State Formula, The National Fire Academy Formula, And the ISO Formula.

Iowa State: Volume of (Enclosed) Room divided by 200 = Gallons required.

NFA: Length x Width divided by 3 = GPM required flow @ 100% involvement.

ISO: A bit more involved, and takes type of construction into consideration.
F = 18 C(A).5 where F=required fire flow, 18 is constant, C=coeeficient based on type of construction, A=floor area. The (A).5 represents the square root of A.

Coefficients of building construction are:
Wood Frame: C=1.5
Ordinary Construction: C=1.0
Heavy Timber: C=0.9
Non-combustible: C=0.8
Fire Resistant Construction: C=0.6

The ISO methods are generally accepted to be more accurate, but used less frequently, if at all, in the field. The ISO method is mostly used on pre-planning.