Combined system - Sprinkler ESFR and IN-rack with Yard hydrant - consider both flowing or one system

[RealKayfactor]

Hi Guys,
back with silly questions. This problem always stumps me - I have a system which will serve hydrants on the plot + Sprinkler ESFR and In-rack system - for the sprinkler system I have considered Inside+outside hose stream allowance - do I still need to consider the hydrant allowance of two more remote flowing simultaneously (which would be 1000GPM) or can I proceed on the basis only one system will be active ?

 

[chicopee]

In depends on the number of hose connections from the fire engines to hydrant nozzles. The number of hydrants will depend on the size and type of building as well as the commodity stored or the type occupancy. I do have guidelines on the required number of hose streams and I'll post them once I check my archives.

 

[chicopee]

This question was asked in the past, so I found my jpeg copy. Now a word of advice as my information is over 30 years old so there may have been updated information, nonetheless, my attachment will give you some inkling into the number of hose stream requirement. I would suggest to corroborate my attachment either with your local fire department, State Fire Marshall or the fire insurance carrier.

 

[UFT12]

IFC Annex B & C or NFPA 1 chapter 18 should give today's figures. Observe especially NFPA 1, §18.4.5.4 or IFC B105.3. Note, the flow of the sprinkler system will have to incluce any additional allowances that may be such as in-racks, hoses, curtains, other special protection etc.

 

[TravisMack]

You have to size this for two different manners.
1 - site fire flow: Size your fire lines and pump/tank (if req'd) to meet site fire flow demands. This is provided that you have hydrants downstream of the pump/tank.

2 - Sprinkler system demand - You size the pump/tank to meet the sprinkler system demands with inside / outside hose allowance as applicable.

Typically, the pump flow is determined by site fire flow requirements. The pump pressure is determined by the sprinkler system demands.

I hope I understood your question correctly.

Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, LLC

http://www.mfpdesign.com

 

[SprinklerDesigner2]

Let's assume your design is 12 K16.8 heads at 52 psi.

The overhead sprinkler is going to require a theoretical minimum of 1,454 gpm but will more likely be in the neighborhood of 1,480 gpm.

To this you need to add the rack sprinkler demand at the point of connection which is usually a manifold at the riser. Hard to guess but let's assume the hose stream demand is 300 gpm.

To the overhead sprinkler and rack system demand you will need to add 250 gpm for hose stream, in some cases depending on the design 500 gpm hose might be required but from my experience that is rather rare, so you are gonna need around 1,480+300+250=2,030 gpm.