Something else to think about Gerzayn: Q=k*p^.5= 16.8*7.071=118.794*(20) heads=2376 GPM minimum. How did you get 2130 demand at BOR?
Brad -----Original Message----- From: [email protected] [mailto:[email protected]] Sent: Tuesday, March 18, 2014 12:55 PM To: [email protected] Subject: RE: 20 K16.8 @ 50 + 500 x 120mins Sounds like you will be trying some different pipe sizes on the sprinkler system. 8" and 4" is a pretty wide spread on the mains. I'd look at pressure losses in the aboveground system and see if you can improve on those. As far as the underground, I'm assuming you are using a plastic pipe (PVP), and from a quick calculation (2,200 gpm) it looks like a velocity of around 16-17 feet per second with a pressure drop around 23-25+ psi for the 900 ft length not taking into consideration fittings. Don't worry too much about the velocity if you're dealing with closed head systems. If you can change the underground to 10" it would be of great benefit to the whole design. One thing that is often overlooked with regard to underground pipe sizes is that fire fighting and suppression is done by manual hose line, not from sprinklers. So the more water available to hydrants, the better. The pump can run up to 3,750 gpm which in an 8" pipe really generates some considerable friction loss. Craig L. Prahl -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Gerzayn Fuentes @ CEPI.MX Sent: Tuesday, March 18, 2014 12:51 PM To: [email protected] Subject: 20 K16.8 @ 50 + 500 x 120mins Good morning to all of you. I have a project for a roll paper storage in a warehouse with 44' height. The FM Global design is 20 K16.8 @ 50 psi + 500 gpm by 120 minutes. The fire pump is 2,500 gpm @ 125 psi and the water tank for 269,924 gals. The preliminary calculations give me 2,130 gals @ 145 psi at the BOR. The pump room and tank is about 900 ft. from the BOR and have 8" PVP pipe. The grid system is: 8" primary main, 4" secondary main, 2.5" branch lines. The sprinkler head are pendent connected through arm-over of 1.5" pipe. The issue here is that the distance and Pipe size from the BOR and Pump give a lot of pressure and velocity. What do you recommend to work around? Booster pump near the BOR? Regards! ________________________________ This year we are focused on improving our service ... Your feedback is extremely helpful. Feel free to support us. Have a safe day! Ing Gerzayn Fuentes Campos | Director CEPI Specialist in Fire Projects. Tel +52 (81) 1766-0800 x 106 | http://www.cepi.mx Regia Vista # 500 | Linda Vista | Guadalupe | Nuevo Leon | Mexico | 67130 _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
