Different situations call for different system types.
Gridded systems allow the water multiple pathways through the system to the operating sprinklers. This means the water travels slower, and we know friction loss increases as the velocity increases, so if a grid reduces the velocity of the...
Also, if the tank is elevated above the pump, there will be additional head pressure on the suction side of the pump. Like pipesnpumps said, Height in Ft X 0.433 psi/ft = PSIhead.
Superior Fire Protection Systems
Protectiong Lives and Property since 1986.
Vancouver, British Columbia...
And at least 12 Sprinklers. Unless superseded by another line of code. What is the storage application?
Superior Fire Protection Systems
Protectiong Lives and Property since 1986.
Vancouver, British Columbia
http://www.superiorfireprotection.ca
Also read 22.4.4.3 in NFPA 13. This should be pretty definitive for you.
Superior Fire Protection Systems
Protectiong Lives and Property since 1986.
Vancouver, British Columbia
http://www.superiorfireprotection.ca
14.4.3
Assuming your system is a grid, you will calculate 4 sprinklers on each of 3 branch lines, for a total of 12 sprinklers. The shape will thus be a rectangle.
Superior Fire Protection Systems
Protectiong Lives and Property since 1986.
Vancouver, British Columbia...
Have a look in the Annex of the NFPA #13
Figure A.22.4.4 should point you in the right direction.
Like Travis says, though, you might have to calculate 'extra' heads if heads are spaced non-uniform.
Superior Fire Protection Systems
Protectiong Lives and Property since 1986.
Vancouver...
You want table 11.2.3.1.2
Basically 90 minutes (monitored) or 120 minutes (unmonitored).
Remember your water supply must meet the system demand for the full duration at the required pressure. If it's a dry system you'll also need to add the capacity of the system.
This seems like a situation...
