Foam sprinkler system

[TravisMack]

Are you required to maintain a uniform discharge in a closed head vs. open head foam system. With a foam deluge system, you are required to size the piping so that any sprinkler does not discharge more than 20% of its required discharge. Is this true of a closed head system as well? I do not do many of these systems, so I just want to check myself.

 

[stookeyfpe]

Travis:

What standard are you citing? NFPA 13 is silent on this (using the 2002 edition).

 

[LCREP]

The closed foam system is the same as a wet system as far as hydraulics are concerned, see NFPA 16. All u need to know is the design density, design area, % of foam concentrate, and duration.

Example, If u look at NFPA 30 2003, table 6.8.2 (d) for 1B liquid <5 gallons, for palletized storage, u need .30/3000, if u use a 3% foam concentrate, .30 x 3000= 900 gpm x .03= 27 gpm for foam concentrate times say 20 minutes of foam duration is 540 gallons of foam. Add 100 gpm for inside hose station, another 3 gpm of foam, or another 60 gallons, so u need 600 gallons of foam concentrate.

I like Viking product Low Flow Foam System, can discharge over a wide range of flows.

Tom

 

[TravisMack]

Reference NFPA 16. I was having a brain fry for the thing and wanted some one else to agree that we didn't need to do the same as for the deluge.