Todd, The effective point is initially the static/residual hydrant and not the flowing hydrant. Idea - flow water past the S/R hydrant. A little math can change that back to the flowing hydrant, but to do that you need the location of the S/R hydrant and a basic understanding of the water system. You are correct in beginning with the perspective the effective point is the intersection of the water main and hydrant leg. Be aware, there are other considerations of how well-gridded or not-gridded the system is. When water purveyors are only willing to provide the location of the flowing hydrant and not much else, it may mean the agency did a single hydrant flow test which complicates the matter. Good sources are, NFPA 291, NFPA 13 and if you are willing M17 from the American WaterWorks Association.
Shawn Shepherd, PE Seattle Fire Department ________________________________ From: cw bamford <[email protected]> Sent: Friday, April 11, 2025 6:30 AM To: Discussion list on issues relating to automatic fire sprinklers <[email protected]> Subject: [Sprinklerforum] Re: Effective point of a flow test. You don't often get email from [email protected]. Learn why this is important<https://aka.ms/LearnAboutSenderIdentification> CAUTION: External Email NFPA 291 from 2022 Fire Pump Handbook 4.4.6 I have used Google Earth Pro It has Elevation (not perfect but close and you can get elevation Change between hydrant(s)) Hose Monster has a Good 8 page PDF on Hydrant Flow Testing Chuck Bamford On Fri, Apr 11, 2025 at 5:29 AM Fpdcdesign <[email protected]<mailto:[email protected]>> wrote: What is the effective point of a hydrant flow test? By that, I mean the point you should design from. I was told from the beginning that it is at the intersection of flowing and non-flowing water (i.e the connection between the point of the flowing main with the branch to the hydrant where the pressures are read.) Am I doing something wrong? This comes from a test that a regional water company did and they will only tell me what hydrant was flowed. It could make a difference because of elevation. Todd G Williams, PE Fire Protection Design/Consulting Stonington, CT 860-535-2080<tel:860-535-2080> (ofc) 860-554-7054<tel:860-554-7054> (fax) 860-608-4559<tel:860-608-4559> (cell) _________________________________________________________ SprinklerForum mailing list: https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org<https://protect2.fireeye.com/v1/url?k=31323334-50bba2bf-31321b84-4544474f5631-405b4061644cfa29&q=1&e=57668acc-8c68-4b77-ab36-2166d14124a3&u=https%3A%2F%2Flists.firesprinkler.org%2Flist%2Fsprinklerforum.lists.firesprinkler.org> To unsubscribe send an email to [email protected]<mailto:[email protected]>
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