Bigger the hole the less pressure to move the same amount of water. The bigger the hole the more water with the same pressure. The water finds the balance by itself and doesn't give a crap what the numbers are, will be, or were. If you plot a line from 84psi at 0 gpm down to Q=29.83c(d^2)(12^0.5) at p (I used your 2.5 nozzle psi but came up with 639 gpm, but I used a 0.98 c for your smooth bore presuming you meant UL playpipe) on a 1.85 log. Then plot a line from 0gpm at 0psi to 243gpm at 60 psi and see if you end up above or below the first line. Below good. Above bad.
On Sun, Jun 23, 2013 at 1:22 PM, Douglas Hicks <[email protected]> wrote: > We a forward flow at a church last week. When we did the main drain flow > test we got 30 PSI. We tested through a single snoot FDC, with the FDC > check valve turned around, the clapper valve was not removed. > #1 forward flow test with 1.5” nozzle. We got 24 PSI, 337 GPM > #2 forward flow test with 2” nozzle, 16 PSI and 493 GPM > # 3 forward flow test with 2.25” nozzle, 12 PSI and 536 GPM > The above results were with a straight fixed nozzle > > The hydraulic name plate > Design Density .10 GPM > Area of operation 917 Sq Ft (the sprinkler protects the basement, which > houses a day care, 2 bathrooms, janitor closet, mechanical room, elevator > room, and a hallway. > System demand at bottom of riser 242.8 GPM at 59.95 PSI > Water supply flow test, 84 PSI static, 70 PSI residual flowing 981 GPM > > > The water flow comes through the wall, 6 inches off the floor, makes a > 90°, up through the backflow device, through the 2.5 inch alarm check > valve, 3 more 90° to the single snoot FDC. Then through the wall and our > flow tester. The water was clean after 1 minute. We did not do a > comparison with a certified gauge, nor did we replace the gauges on the wet > pipe. > > The chart is supplied with the flow tester. > > Do these results look legitimate? A larger nozzle = more GPM and less PSI? > _______________________________________________ > Sprinklerforum mailing list > [email protected] > > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > -- Ron Greenman Instructor Fire Protection Engineering Technology Bates Technical College 1101 So. Yakima Ave. Tacoma, WA 98405 [email protected] http://www.bates.ctc.edu/fireprotection/ 253.680.7346 253.576.9700 (cell) Member: ASEE, SFPE, ASCET, NFPA, AFSA, NFSA, AFAA, NIBS, WSAFM, WFC, WFSC They are happy men whose natures sort with their vocations. -Francis Bacon, essayist, philosopher, and statesman (1561-1626) _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
