It would be interesting if you make a flow near the riser, take static and residual pressure next to the riser and on the street hydrant (simultaneously) and then note the differences.
Dan -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dewayne Martinez Sent: Monday, May 12, 2008 2:30 PM To: sprinklerforum@firesprinkler.org Subject: RE: Change in static pressure After doing the math the pressure loss can be accounted for by the change in elevation and the loss through the backflow at the low flow. I was unaware of the loss in pressure with no/little flow on the BFP. Thanks for everyone's input on the matter. Dewayne -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dewayne Martinez Sent: Friday, May 09, 2008 1:59 PM To: sprinklerforum@firesprinkler.org Subject: RE: Change in static pressure Thanks, I will look into the cut sheet. The fitter preformed an alarm test so only a small amount of water was flown. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Paul Pinigis Sent: Friday, May 09, 2008 1:22 PM To: sprinklerforum@firesprinkler.org Subject: RE: Change in static pressure Look at the cut sheet on the BFP. Some BFPs require a significant amount of pressure to open at very low flows. For example, an 12" Ames 2000SS requires almost 6 psi to operate at very low flow so it can sit there all day with an upstream pressure nearly 6 psi higher than the system side pressure. Paul J. Pinigis, P.E. Chief Life Safety Engineer -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dewayne Martinez Sent: Friday, May 09, 2008 1:55 PM To: sprinklerforum@firesprinkler.org Subject: Change in static pressure I have a job site which is 10ft higher than the water supply. A gauge on the water supply hydrant reads 55 PSI static pressure while two gauges on the system riser after the BFP read 37 PSI? The total elevation change between the system gauges and the supply gauge is about 17ft. Why would there be a 18 PSI difference between the gauges when elevation only accounts for 7.36 PSI? I confirmed with the city that there are no shut valves. Any thoughts? Thanks, Dewayne _______________________________________________ Sprinklerforum mailing list Sprinklerforum@firesprinkler.org http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list Sprinklerforum@firesprinkler.org http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list Sprinklerforum@firesprinkler.org http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list Sprinklerforum@firesprinkler.org http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field) __________ NOD32 3092 (20080512) Information __________ This message was checked by NOD32 antivirus system. http://www.eset.com _______________________________________________ Sprinklerforum mailing list Sprinklerforum@firesprinkler.org http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field)