I have always used the suction flange size of the fire pump. The suction pipe size and backflow preventer size can vary. I will look at NFPA 20 when I have a chance and see if I can find a reference for you.
Thanks, John John August Denhardt, PE *Vice President, Engineering and Technical Services* *American Fire Sprinkler Association* m: p: 301-343-1457 214-349-5965 ext 121 w: firesprinkler.org Sprinkler Hydraulic Calculations Workshop AFSA’s three-day, in-person workshop provides a deep dive into the principles of hydraulics, including the different types of pressure, calculating changes in pressure (elevation and friction loss), and node analysis. Click here <https://www.firesprinkler.org/programs/calculations/> for details and to register. On Sat, Oct 7, 2023 at 10:52 AM Fpdcdesign <[email protected]> wrote: > Fire pump is a 250 gpm at 60 psi > > Todd G Williams, PE > Fire Protection Design/Consulting > Stonington, CT > 860-535-2080 (ofc) > 860-554-7054 (fax) > 860-608-4559 (cell) > > > On Oct 7, 2023 at 10:48 AM, <Tstone52 <[email protected]>> wrote: > > Todd, > > > > According to NFPA 20, 2013 ed., 4.26, Table 4.26 shows 4” minimum suction. > > > > 2022 ED. Is the same. > > > > Regards, > > *G. Tim Stone* > > > > *G. Tim Stone Consulting, LLC* > > *NICET Level III Engineering Technician* > > *Fire Protection Sprinkler Design* > > *and Consulting Services* > > > > * 117 Old Stage Rd. - Essex Jct., VT. 05452* > > * CELL: (802) 373-0638 * > > [email protected] > > > > *From:* Fpdcdesign <[email protected]> > *Sent:* Saturday, October 7, 2023 10:16 AM > *To:* Discussion list on issues relating to automatic fire sprinklers < > [email protected]> > *Subject:* [Sprinklerforum] Distance to fire pump suction > > > > I have a system with a 6” backflow preventer, which reduces to 4” > immediately after. There is approximately 48” of 4” pipe to the suction > flange on a 4 x 3 pump. All elbows are turning correctly. Is this > sufficient? Does the 10x rule apply to the size of the backflow preventer > or the fitting directly attaching to the pump? > > > > Todd G Williams, PE > > Fire Protection Design/Consulting > > Stonington, CT > > 860-535-2080 (ofc) > > 860-554-7054 (fax) > > 860-608-4559 (cell) > _________________________________________________________ SprinklerForum > mailing list: > https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org > To unsubscribe send an email to > [email protected] > > > _________________________________________________________ > SprinklerForum mailing list: > https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org > To unsubscribe send an email to > [email protected]
_________________________________________________________ SprinklerForum mailing list: https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org To unsubscribe send an email to [email protected]
