Without sounding harsh the committee screwed up with the advent of non straight tip nozzles. IMHO minimum pressure should be removed and replaced with ask the fire chief (not the fire marshal). You are right 100 doesn't get you much.
Chris Cahill Fire Protection Engineer Burns & McDonnell 952-656-3652 [email protected] -------- Original message -------- From: Brad Casterline Date:02/19/2014 9:51 AM (GMT-05:00) To: [email protected] Subject: 100 PSI requirement at top of Standpipe Does anyone know why the technical committee settled on 100 PSI minimum at the 2.5" hose valve? It used to be 75 PSI, and for High Rise retrofit I have seen AHJs accept 75. I am just curious because I think with about 60 PSI at the 2.5" connection to the standpipe we could get about 250 GPM at the nozzle, figuring the Pf for the T, 2.5x0-6 nip, hose valve, and 100 feet of 2.5" hose. A 15 psi safety factor seems reasonable, but 40 psi??? I know the F.D. might want to use a 2.5x1.5 reducer and 1.5" hose, but with 150 GPM flowing through 100 feet of 1.5" hose the Pf in the hose alone is about 162 PSI! So, I don't get it, but I am likely missing some simple explanation, so I'm asking. thanks, Brad Casterline, NICET IV Fire Protection Division FSC, Inc. P: 913-722-3473 [email protected] www.fsc-inc.com<http://www.fsc-inc.com> Engineering Solutions for the Built Environment _______________________________________________ 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
