Where are you reading 15-psi? If it’s before the RPZ backflow preventer, then check with the local water utilities to see what they recommend. Creating pressure below 20-psi in the city supply is not a good condition.
If it’s after the backflow preventer at the pump suction flange, then I don’t think it’s a problem as long as you don’t drop below 0-psi. Just my honest opinion Rick Matsuda > On Jun 24, 2025, at 11:20 AM, Christopher S. Wilson <[email protected]> > wrote: > > > Does this only happen when you take the pump to 150%? > > > > Christopher S. Wilson > Project Design Manager, SET > > (208) 872 1128 > [email protected] > > Treasure Valley Fire Protection > A Pye-Barker Fire & Safety Company > 2731 Saturn Way > Boise, ID 83709 > > > pyebarkerfs.com > > > From: Fpdcdesign <[email protected]> > Sent: Tuesday, June 24, 2025 10:17 AM > To: Discussion list on issues relating to automatic fire sprinklers > <[email protected]> > Subject: [Sprinklerforum] Re: [EXTERNAL] Backflow turbulence > > The water supply tested in the street to 38 psi with less than 5 ft elevation > to the pump room. The suction pressure they are getting during the pump test > is 15 > > Todd Williams > Fire Protection Design/Consulting > Stonington, CT > 860-608-4559 > > > > On Jun 24, 2025 at 11:39 AM, <Craig Prahl> wrote: > > Are suction pressures low due to the water supply? Since there is a BFP, I > assume you’re drawing from a city service, correct? Got any data on that > system? > > Craig Prahl | Jacobs | Fire Protection SME – EV, AM, DC, Special Hazards > [email protected] | www.jacobs.com > 1041 East Butler Road Greenville, South Carolina 29606 > CONTACT BY: Phone 1-864-676-5252, Email or MS TEAMS > > > From: Fpdcdesign <[email protected]> > Sent: Tuesday, June 24, 2025 10:45 AM > To: Sprinklerforum <[email protected]> > Subject: [EXTERNAL] [Sprinklerforum] Backflow turbulence > > I am working on an untestable fire pump with an “N” shaped RPZ in the suction > line. They (just) have the 10X diameter distance on the feed, but the suction > pressures are very low (15 psi). It seems that an “N” shaped device would > create a lost > I am working on an untestable fire pump with an “N” shaped RPZ in the suction > line. They (just) have the 10X diameter distance on the feed, but the suction > pressures are very low (15 psi). It seems that an “N” shaped device would > create a lost more turbulence than a standard straight one. Consequently, > should the distance of straight pipe requirement be greater for this > arrangement? > > Todd G Williams, PE > Fire Protection Design/Consulting > Stonington, CT > 860-535-2080 (ofc) > 860-554-7054 (fax) > 860-608-4559 (cell) > > > NOTICE - This communication may contain confidential and privileged > information that is for the sole use of the intended recipient. Any viewing, > copying or distribution of, or reliance on this message by unintended > recipients is strictly prohibited. If you have received this message in > error, please notify us immediately by replying to the message and deleting > it from your computer. > _________________________________________________________ SprinklerForum > mailing list: > https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org > To unsubscribe send an email to [email protected] > > > Disclaimer > > This email may contain confidential and privileged material for the sole use > of the intended recipient(s). Any review, use, distribution or disclosure by > others is strictly prohibited. If you are not the intended recipient (or > authorized to receive for the recipient), please contact the sender by reply > email and delete all copies of this message. PLEASE PRINT RESPONSIBLY. > > > _________________________________________________________ > SprinklerForum mailing list: > https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org > To unsubscribe send an email to [email protected]
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