Flow for sprinkler system

[phots]

Newbie here,

I am a little bit confused about calculate total flow for warehouse sprinkler.
I am using NFPA 13-2013 Table 16.2.3.1 ESFR Sprinkler protection of rack storage.
Base on Table i got information like this:
1. Maximum storage height 6.1m
2. Maximum ceiling / Roof Height 10.7

So i am using 14.0 Kfactor and minimum operating pressure is 75.
If i calculate using Q = k* p^0.5 is
= 14.0 x 75^0.5
= 121.24 GPM

121.24 is a flow for 1 sprinkler rights?
so if i calculate for 13 sprinkler it will be 121.24 x 13 = 1576.17 GPM
Is my calculation is correct?
or there are any way to reduce total flow?

 

[TravisMack]

With ESFR, you only calculate 12 sprinklers. Also, there will be some overage due to inefficiencies in all mechanical systems. If this is a gridded system, you should only see about 5% overage. If it is a tree, you could see as much as 20-30% overage of flow.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[LCREP]

Do not forget the required 250 GPM for FD hose so your flow will be about 1,826 gpm. If the water supply is from a tank you will need to provide the flow for 60 minutes= 109,560 gallons.

 

[phots]

TravisMack: is there any statement in NFPA to calculate only 12 ESFR Sprinkler? Please let me know.

LCREP: How to determine discharge time for ESFR Sprinkler? Why shouldn't i add 500GPM for FD Hose?

Thank you for your response

 

[LCREP]

Check NFPA 13 the number of sprinklers, 12 and GPM 250 are listed for ESFR systems.

 

[ABdesigner]

22.4.4.3 ESFR Sprinkler Method. For ESFR sprinklers, the design area shall consist of the most hydraulically demanding area of 12 sprinklers, consisting of four sprinklers on each of
three branch lines

 

[cdafd]

Dealing with storage and esfr heads you might want to get the assistance of a FPE, that has dealt with storage and esfr

 

[TravisMack]

Phots:

I don't mean to sound rude, but some of those questions are pretty rookie questions. I would not be missing with ESFR systems if I wasn't confident in what was going on. Storage protection is much more specific than your typical light and ordinary hazard areas.

You will likely want to get some one with quite a bit more experience to review everything when you have it all together.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com