Hey George! Yes, Vince wanted to calc a hose valve as if it was a head, and not a demand calc. Since "K" is the Area, it is the thing that does not vary as Q as P. And yes K for a 2.5" hose valve has to be empirically derived, but only one of them, and hope the rest are made close to the same size :). I cannot think of anything simpler than using feet and seconds only- for me it lifts the magic fog of "Redbook" sprinkler calcs of Q's, P's and K's. It also simplifies metric conversions since seconds is the unit of time for both systems. g=9.81 meter/sec (32.2/9.81=3.28 ft/m). Thanks for caring, I always appreciate the attention.
-----Original Message----- From: George Church [mailto:[email protected]] Sent: Monday, April 16, 2012 12:51 PM To: [email protected] Subject: RE: k -- WHAT? Wasn't it a hose valve for forward flushing of the BFP that was the original question? And don't K factors have to be empirically derived? I once tried to determine the logo sprinkler atop a building wherein I worked in 1988, and was told without drilling a hole where the orifice was and pumping a LOT of water thru it, we couldn't determine it via formula. I was talking to folks in Lansdale that I think know a lot about large K factors, even back in the 80's. If I were to try to determine how many 2.5" FHV I needed to flow a certain value, I'd simulate it with a test header. Can't think its much different than the # of FHVs needed per #20, and we've been doing that far longer than we've been using even hand calcs. KISB. Keep It Simple, Brad. This is an imprecise business, deal with it. George L. Church, Jr., CET Rowe Sprinkler Systems, Inc. PO Box 407, Middleburg, PA 17842 877-324-ROWE 570-837-6335 fax [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Brad Casterline Sent: Monday, April 16, 2012 11:37 AM To: [email protected] Subject: RE: k -- WHAT? But since friction head with turbulent (sprinkler) flow is proportional to the velocity squared, and the data from Ron Greenman's link says 'K Value for use in the formula hf=k(v^2/2g)', and the velocity varies as the flow, wouldn't the K Value give us the friction loss 'curve' we are looking for, as opposed to an average over a range? -----Original Message----- From: Roland Huggins [mailto:[email protected]] Sent: Monday, April 16, 2012 10:00 AM To: [email protected] Subject: Re: k -- WHAT? I started to say before getting overly precise (but that horse has left the barn), it might be helpful to keep in mind that the K valve on a sprinkler is NOT a constant at different flows. It is an AVERAGED result for flows from 7 psi to 100 psi. Roland _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum
