Yep, our jurisdiction requires 15 psi to account for the fire meter as well. Jamie Seidl
> > On Jun 4, 2021 at 6:04 PM, <321 via Sprinklerforum > (mailto:[email protected])> wrote: > > > > Just a quick word of caution...those RPZs are killers on Light Hazard > Systems with low flows. I have to use them here in the Florida Keys due to > the vulnerability of our water system, but if I had a choice I would be using > DDCAs. I just automatically plug in a 12 PSI loss when I'm moving 300 Gallons > or less. John Farabee | Certified Lower Keys Plumbing and Fire | C: > 561-707-5150 (tel:561-707-5150) | F: 305-294-2462 (tel:305-294-2462) John > W. Farabee 561-707-5150 (tel:561-707-5150) On Friday, June 4, 2021, > 04:55:34 PM EDT, Matthew J Willis via Sprinklerforum > <[email protected] > (mailto:[email protected])> wrote: That seems correct. > The annex speaks to this. Elevation above water supply, plus the backflow > loss. There is no other mention of pipe, fittings, etc. R/ Matt -----Original > Message----- From: Sprinklerforum > <[email protected] > (mailto:[email protected])> On Behalf Of J amie Seidl via Sprinklerforum Sent: Friday, June 4, 2021 2:14 PM To: Sprinklerforum <[email protected] (mailto:[email protected])> Cc: Jamie Seidl <[email protected] (mailto:[email protected])> Subject: pipe schedule/residual pressure I am looking at a project where we are renovating an existing building with a new system. There are other buildings on the site (1930's vintage) that share the underground lines. To bring the site into compliance with current codes, RPZ backflows are being added at the entrance to the site. The existing buildings are occupied, and the fire department is looking for some assurance that the systems will work with the addition of the backflow preventer. I remembered (though have never applied it) section 11.2.2.8 allows for the calculation of the residual pressure at the highest sprinkler, and deducting elevation, BFP losses ect... The buildings in question are over 5000 sqft, so the minimum 50 psi will apply. So my question is, do I just utilize the residual pressure from the closest hydrant, deduct the elevation and backflow losses from the residual and call it a day? Or do I need to account for additional friction through the system piping? Both 13 and the handbook seem to be mute on this. Thanks again, Forumites. Jamie Seidl _______________________________________________ Sprinklerforum mailing list [email protected] (mailto:[email protected]) http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] (mailto:[email protected]) http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] (mailto:[email protected]) http://list s.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > > _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
