Water demand Calculation for sprinkler system and Standpipe system with separate risers

[Miyazaki]

Hello All,

I am a bit confused while calculating water demand for sprinklers and standpipe system which has separate risers, do I need to calculate both demands (standpipe & sprinkler) separately and add both demands? Because only in combined system NFPA 13 & 14 says to consider the largest water demand(NFPA 13 19.2.6.4 & NFPA 14 7.10.1.3.1). Could anyone please guide me here with some reference in NFPA.

 

[SprinklerDesigner2]

In a fully sprinklered building both are calculated separately.

If the building has sprinklers throughout and two standpipes your total demand would be 750 gpm. Next you would calc the sprinklers and maybe end up with 322 gpm at the base of the riser with a total of 572 gpm with 250 hose stream.

The only time you combine both sprinkler and standpipe is in a partially sprinkled building which is something I've never encountered. I'm sure it exists but I've never seen one.