ISO Fire Flows
ISO Fire Flows
(OP)
I am just curious about what might be the ISO fire flow for 65,000 sq ft non-combustible UPS type terminal building?
The building has full wet pipe system and it is in a big field with nothing around it but open space 500' in any direction.
Water at the street is 50 static, 20 residual flowing 750 gpm and even with the building sprinklered my gut tells me it doesn't meet the ISO fire flow requirement.
1,000 gpm? Nahhhh... I found some online spreadsheets and it is looking more like 2,000 gpm? A 1,500 gpm pump needed for an OH2 sprinkler system?
I am not using this information for anything other than I am simply curious... the only answer that would count in my book would be from the building professional of record because the decision sure as heck ain't mine to make!
The building has full wet pipe system and it is in a big field with nothing around it but open space 500' in any direction.
Water at the street is 50 static, 20 residual flowing 750 gpm and even with the building sprinklered my gut tells me it doesn't meet the ISO fire flow requirement.
1,000 gpm? Nahhhh... I found some online spreadsheets and it is looking more like 2,000 gpm? A 1,500 gpm pump needed for an OH2 sprinkler system?
I am not using this information for anything other than I am simply curious... the only answer that would count in my book would be from the building professional of record because the decision sure as heck ain't mine to make!





RE: ISO Fire Flows
The important take away from this is, perhaps, that fire flows and sprinkler demands are two different animals.
I believe the ISO calculation is used to determine some insurance rates for building owners and insurance rates for cities.
RE: ISO Fire Flows
If we have 750 gpm @ 20 psi available from the city main then a 1,000 gpm pump should do the trick delivering a total of 2,250 gpm @ 20 psi?
It appears the civil engineer came up with the 150,000 gpm tank and that has to be to meet the fire flow. Darn tank is coming to better than $200k once the foundation and pumphouse is added to it.
RE: ISO Fire Flows
Since the sprinkler system to the terminal was undoubtedly hydraulically calculated, check the data plates attached to the sprinlker alarm check valves for additional information about the water requirement and supply
RE: ISO Fire Flows
Given the fire flows made available to us a tank, probably 150,000 gallons, has always been in the equation. Given a 20 psi residual at 750 gpm if fireflows are required the largest pump I would dare put on that line would be 400 gpm.
RE: ISO Fire Flows
650 gpm * 120 = 78k gallons. So, your tank, provided with an automatic fill line and float valve would need to store 240k-78k gallons, or 162k gallons.
For your fire pump, you are going to need a minimum of 1500 gpm pump as a 1250 gpm won't be listed to give 2000 gpm @ 150% of capacity. So, the 1500 gpm pump is your capacity. Since you are getting a pump no matter what, I would look at a rating that will be the highest you can get based on power to the building. I mean if you are already putting a pump in, you may as well get the biggest bang for the buck in pressure so you can reduce your fire sprinkler system piping.
Travis Mack
MFP Design, LLC
www.mfpdesign.com
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