Standpipe calculation 2

[ABdesigner]

Hello Forum members,

In a 06 storey 60 ft high Residential building (Not a High-Rise Building as per Def. 3.3.5 (NFPA 14)) I don't have to follow 7.10 and calculate standpipes accordingly? Is my thought process Correct ? because it can be classified as manual standpipe ? Automatic Standpipes are only required in High-Rise Buildings (>75') and have to follow design requirements as per NFPA 14 ?

The residential building in the case is allowed to have Manual standpipe Sys. without any calculations ? For the most part I understand the design requirements in section 7 (NFPA 14) but not sure when I have to apply those and when I don't.

Also, the building owner wants to have Fire pump sized such way to have 100 psi at the top of the standpipe. What flow @ 100 Psi I have to calculate the standpipe ? is 250 gpm @ 100 Psi correct ?

Thanks for your time.

 

[TravisMack]

Almost all standpipes are going to have a pump. In the case of a manual standpipe, the pump is the fire truck. You typically calculate to 150 psi @ 1000 gpm at the FDC inlet. There is some guidance in the annex of NFPA 14 for the pressures to use, or you can contact the local FD and they should be able to tell you.

However, you must calculate all systems. How are you going to size it if you don't calculate it. I don't believe standpipe pipe schedules are allowed any longer.

If the owner wants you to have 100 psi at the top with an automatic supply (on site fire pump) then just figure out how short you are from the city and provide a pump that will make up the difference.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[ABdesigner]

Travis,

perfect, that clears my preliminary concept for standpipes design, sizing and calculation.
Also was missing the fact that Building code takes precedence over NFPA standards.

Thanks for your input.

 

[SprinklerDesigner2]

ABdesigner,

And the building code can certainly be different from state to state.

I think Georgia is rather unique, that is as far as I know, in that as long as the building is not a high rise and everything is run in 8" diameter there are not any calculations involved at all. That's right, we can have a six story (70' to roof level) building with 50 static, 25 psi residual @ 600 gpm at the street and it flies as long as everything, as in literally everything, is 8" diameter no calculations are required.

The sprinkler system presents some challenges but it can be done... you won't have any friction loss through the standpipe piping.

If you don't like the 8" pipe then you can go with a fire pump and ground storage tank. 8" pipe is easier and cheaper.