Asghar Khan (Visitor)    Feb 5, 2002
Dear bob,
Steps:
1. make a Fire water pipeline ring loop around the plant.
2. provide block valves in the loop so that in case of any isolation no more than 1000 ft of pipe containing hydrants, hose reels, monitors or sprays can be lost.
3. hydrants should be spaced at 300 ft along the roadways in offsite area and 150 ft in the process area.
4. design hydrants and monitor nozzles at 500 gpm.
5. design sprinker at 30 psi, gpm= K x under root of line pressure. example for 30 psi it shall be 16.43 gpm, where K is the nozzle factor and take it equal to 3.
6. keep spray nozzles 8 ft. apart, it shall form an umbrella of water spray  to cut off the air supply in case of fire.
7. pipeline pressure should be in between 120 and 150 psior the grid pressure should be around 100 psi.
8. you need a pump and a jocky to ride on.
TAKE CARE AND GOOD LUCK.
Asghar Khan

Of course there are also various standards for this, particularly NFPA and FOC standards ("National Fire Protection Association" and "Fire Office Commision", respectively, as i recall).  A useful software tool designed just for such problems, and based on these standards, is the PIPENET Spray/Sprinkler software module by Sunrise-Systems in Cambridge, England.  It is used rather widely for offshore oil platforms, petrochemcal plants, etc. Purchase of a perpetual license may be easily justified for your problem solving.  The software module calculates hydraulics for complex networks and ringmains, deluge systems, etc, line sizes and schedules, nozzle sizes and spacing needs, flow densities as required by code, etc.  See http://www.sunrise-sys.com/ ; Handy little item.

Wayne at www.DeltaCascade.com