Rated Fire Flow

Just a little something for you die hard fire hounds out there like myself. How about some equations on how you figure rated fire flow for a structure in your districts or whatever your apart of???

For intance ours is Length X Width

_______________ (Divided)

Now for us this gets you a 100% involvement and in the case only a 1/4% is involved we multiple the number of 100% you come up with on the above equation by .25 or so on with how ever much is being eaten and that gives us a pretty close figure of how many lines we need on the ground to supply the wet stuff on the hot stuff, make since?

In layman's terms or whatever terms you use lets say the fire is calling for 800 gpm for fire suppression (You know put the wet stuff on the hot stuff and your useing 2-1/2" hose and 2-1/2" adjustable gallonage nozzles which most nozzles and not all are capable of 250 gpm and not exlude friction loss of lets say we have 200' (foot) down on the ground per connection of 2-1/2" hose, with that being said approximately 10 psi per a 100' of hose of friction loss then we would need how many lines on the ground to handle this fire????

The answeer is approximately Four (4) preconnects of 200' of 2-1/2" hose with a nozzle capable of 250gpm on each preconnect with one heck of a water load feeding that truck....

Now this is just a short version we use and is very quick with that handy-dandy cell phone everyone has in there pocket that has a calculator in the tools part...

Now its your turn to give everyone food for thought and lets learn something new today!!!!!!

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Permalink Reply by CHIEF NORMAN on May 24, 2010 at 9:35am

Well these days guys we as chief officers have to wear many hats, not just the chief’s hat and driving around in that pretty red truck, but we have to be part politician and not to exclude an attorney at law and so on. Some people say what does this have to do with rated fire flow...Well plenty!!! Everything that go's on from the time those tones go off until you’re on that scene and doing what you do best all reflects on your job and anything someone does or doesn’t do has consequences. And with that being said Dan your right! It can be ammo and you as a politician can preach your needs and have your needs meet if your prepared, but on the other hand a good attorney will eat you alive if you have a commercial fire and that fire go's to court and you haven’t done your pre fire plane or done rated fire flow on that scene and don’t have documentation showing that. Preparation is the key!!! My hats off to ya brother's and if ya stay smart... ya stay alive...

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Permalink Reply by Russ on May 24, 2010 at 10:41am

Just Curious...how often do engineers look at how we calculate fire flow and pump calculations and how are they confirmed? is there a new math on the horizon?