I would consult the local FD and see what the fire pumper truck is rated at. If they have a 1500 gpm pumper the curve might be more to your liking.
On Tue, Mar 22, 2016 at 8:31 AM, <[email protected]> wrote: > Sorry for coming into this a week late. We have recently been dealing > with specs and AHJ requirements that state we need to supply 130psi and/or > 140psi at the top outlet regardless of whether it is manual or automatic. > Same flows as outlined in NFPA 14 (500gpm +250gpm per standpipe up to > 1000gpm). The fire pumper truck is still sized for 150psi @ 1000gpm. What > do you suggest we do if we can only set the FDC to be the source of 151@0 > and 150@1000? Some building are still 70ft tall and the standpipe is > still a manual wet. Only accounting for elevation we are looking at > 160psi/170psi demand at the FDC. Even if your answer is make it an > automatic standpipe, the 140psi requirement limits the "manual" standpipe > building height to 23ft when we don't account for friction loss using your > calculation procedure. So we can't even meet these manual FDC 150psi calcs > on a building that doesn't even need a standpipe. > > Thanks, > Sean VG > > > > -----Original Message----- > From: Sprinklerforum [mailto: > [email protected]] On Behalf Of Steve Leyton > Sent: Monday, March 14, 2016 3:57 PM > To: [email protected] > Subject: RE: Standpipe Calc: Adding City Demand to Pumper Truck? > > Tony: > > You (or the submitter) are over-simplifying what the annex says. It's not > the intent that you take the city flow test and add it to the pumper > curve. NFPA 1901 sets the basic performance curve for a pumper at 150 > PSI/1,000 GPM. NFPA 13E is the standard for FD Operations for buildings > equipped with sprinklers and standpipes - that standard goes into the > company engineer's procedure for calculating the discharge pressure of the > pump based on suction pressure, friction loss in hose and other variables. > But the bottom line is that it's all targeted at discharging 150 PSI > residual at 1,000 GPM. This has NOTHING to do with pressure at the FDC; > it has to do with calculating the performance of the apparatus. What gets > to the FDC is up to the engineer. > > Which is why 7.7.4 states, "When the system demand to be supplied by the > fire department at the fire department connection is being determined, the > local fire department shall be consulted regarding the water supply > available from a fire department pumper." FROM A FIRE DEPARTMENT > PUMPER. It's up to the incident commander and his or her engineer to > determine the suction pressure and set their discharge to whatever is > required to make their programmed starting pressure. And based on the > nationwide standard and best practices, that is almost certain to be 150 > PSI at the prescribed flow rate. The engineer will calculate the friction > loss in the discharge hose that's connected to the building. If you are > reviewing plans that show 150 PSI residual plus a positive suction head at > that flow rate as the inlet pressure, then that is almost certainly not > correct. > > To answer your question, if I have a building with two (750 GPM) or three > or more (1,000 GPM) standpipes, we plug in a "flow test" static pressure of > 151 PSI and a residual of 150 PSI at the target flow rate and we run the > calc' using the FDC as the "city connection". We plug in a 500 PSI hose > stream allowance at the most remote standpipe outlets and at 250 GPM hose > streams at those points in the bulk main system where the other risers take > off. We allow 5 PSI for loss in a standard hose valve so the minimum > pressure at any node is 105 PSI. > > The foregoing is my opinion only and does not represent the opinion of or > any manner of interpretation by NFPA or the Technical Committee on > Standpipes. > > Steve Leyton > > -----Original Message----- > From: Sprinklerforum [mailto: > [email protected]] On Behalf Of Tony Eggster > Sent: Monday, March 14, 2016 3:24 PM > To: [email protected] > Subject: Standpipe Calc: Adding City Demand to Pumper Truck? > > Quick question: I'm reviewing some plans for a manual class I standpipe > and the designer added the city flow test to the usual 1000gpm fire pumper > curve in order to keep all the pipe down to 4". I see in the NFPA 14 > appendix that you can do this but personally I've always just calculated > solely to the pumper curve. How do you guys do it? > > Also, I'm assuming that if you do factor in city supply wouldn't that > frequently require high pressure pipe and fittings depending on city supply > psi? > > _TONY > _______________________________________________ > 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 > _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
