The worst case is 252GPM @ 59 PSI with no inside hose. When I plot this on the adjusted water curve it is below the curve but does not meet the 10% minimum safety factor required. I think I will try to run a new flow test to try and get to the bottom of things.
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Thom McMahon Sent: Monday, December 14, 2009 12:53 PM To: [email protected] Subject: RE: forward flow test problem My question is what is the system demand? I believe that we are required to "Forward flow the system demand" Example: system demand for LH building with 9'0" ceiling could be as low as 90 GPM (0.1GPM @ 900SF) So what is the hydraulic data plate requirement? What is your system demand? Any inside hose streams? What does the Hydraulic data plate say? Thom McMahon, SET Firetech, Inc. 2560 Copper Ridge Dr P.O. Box 882136 Steamboat Springs, CO 80488 Tel: 970-879-7952 Fax: 970-879-7926 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Ron Greenman Sent: Monday, December 14, 2009 11:34 AM To: [email protected] Subject: Re: forward flow test problem I just graphed it on a 1:85 log scale. 67psi at 0 gpm static, 50 psi at 715 gpm residual, and extend the "curve" out and you'll get 40 psi at 900 flowing. These are all just close because you have to account for the thickness of lines and size of points but accurate enough for discussion purposes. On Mon, Dec 14, 2009 at 9:48 AM, Dewayne Martinez <[email protected]> wrote: > The BFP is at the riser. > The flow was through the 2 1/2" connection on the wall hydrant. The hydrant at the road had the 2 1/2" outlet flowed for the original test. I am curious how you got 40 PSI at 900GPM? > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Ron > Greenman > Sent: Monday, December 14, 2009 11:32 AM > To: [email protected] > Subject: Re: forward flow test problem > > Where is the backflow device? If at the riser and that is 10 feet > higher than the test hydrant as you say then the static is correct. 72 psiI less 4.33 psi for elevation equals as close to 67 psi as I can read on a gauge. I also plotted these results and got about 40 psi at 900 gpm. What size orifice are you flowing through? Is it the same as was flowed on the hydrant? > > On Mon, Dec 14, 2009 at 8:45 AM, Dewayne Martinez <[email protected]> wrote: >> We have a job where the residual pressure recorded during the >> backflow test is lower than expected. The hydrant used for the >> original water test is about 10ft lower than the system riser and has >> a flow test result of 72PSI static, 62PSI residual, flowing 902GPM >> (off a circulating system). I had my fitter install a pressure gauge >> before the 1st check on the BFP and the we recorded a static of 67PSI >> but a residual of 50PSI at a flow of 715GPM. I confirmed with the >> water utility that the gate valve for the water lead in is fully open >> and that no pumps or valves have been shut off for water main breaks >> or maintenance. Unfortunately, they will not run a new flow test in >> winter. >> Any ideas as to what is causing the low residual pressure? >> Thanks, >> Dewayne Martinez >> Design Build Fire Protection >> New Berlin, WI >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum >> >> For Technical Assistance, send an email to: [email protected] >> >> To Unsubscribe, send an email >> to:[email protected] >> (Put the word unsubscribe in the subject field) >> > > > > -- > Ron Greenman > Instructor > Fire Protection Engineering > Bates Technical College > Tacoma, WA > > Member: > SFPE, ASCET, NFPA, AFSA, NFSA AFAA, WSAFM > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email > to:[email protected] > (Put the word unsubscribe in the subject field) > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email > to:[email protected] > (Put the word unsubscribe in the subject field) > -- Ron Greenman Instructor Fire Protection Engineering Bates Technical College Tacoma, WA Member: SFPE, ASCET, NFPA, AFSA, NFSA AFAA, WSAFM _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
