What type of system, commercial, residential????????????????? In an NFPA 13 system what are you plugging in for your calcs if all you have is a "city pressure"? Is that static or residual? How does a single pressure point relate to flow or establish any kind of flow curve?
If all you know is 50 psi, and that's let's assume a static pressure on a gauge, you could have any value for flow (gpm) and residual probably no less than 20 psi. But you have no real idea of what kind of water supply you have based on one value alone. I'm speaking purely from a commercial/industrial side of calculations. Maybe residential allows you other ways of calculating, I don't' deal with Res. So can't speak to the methodology on that side. NFPA 13 gives you some guidance on how to calculate a system, if you don't see this method there, it's for a reason. Craig L. Prahl Fire Protection Group Lead/SME CH2MHILL Lockwood Greene 1500 International Drive Spartanburg, SC 29303 Direct - 864.599.4102 Fax - 864.599.8439 CH2MHILL Extension 74102 [email protected] -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of Sean Lockyer Sent: Tuesday, October 20, 2015 6:24 PM To: [email protected] Subject: Is calcing back to the riser gauge acceptable ? Quick question for everyone here. When the situation prevents one from being able to provide a calculation back to the U.G. connection at the street when can you calculate the system back to the gauge on the riser ? For example, if you have, say, 50 psi city pressure (worst case) on a system at the riser gauge couldn't one calc it to the base of the riser, add in your hose allowance and call it a day as long as your system demand is less than the lowest "day pressure" in the system ? In addition, if there any mention on this in NFPA 13 ? Sean Lockyer Project Designer 4617 Parkbreeze Court Cell 386-279-1197 Orlando, Florida 32808 [email protected] Phone: 407-816-9101 www.AITLifeSafety.com Fax: 407-816-9104 _______________________________________________ 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
