Uhhhhhh … maybe it’s a 4” port? From: Sprinklerforum [mailto:[email protected]] On Behalf Of Brad Casterline Sent: Friday, February 24, 2017 4:19 AM To: [email protected] Subject: Re: Do Hydrant Butts have a K Factor?
Just one more thing if the Forum will suffer me-- A while back I was looking at some flow test data and I thought I had the size and type of butt figured out to be 2.5" C=.9. Static= 112 psi Residual= 98 psi Pitot= 40 psi 4320 gpm @ 20 psi Something was bothering me because if it was a 2.5" C=.9 I get 2912 gpm @ 20 psi. I Googled 'California hydrant butts' thinking they might have some weird size butts and after I got past a hot chick exercising outside didn't see anything unusual. So it's still a puzzle for me and I don't want to bother the poster of that data, hoping someone here has a simple explanation. Thanks, Brad . On Feb 23, 2017 3:09 PM, "Brad Casterline" <[email protected]<mailto:[email protected]>> wrote: Good advice on using the NFPA formulas Travis, thanks, and when I am 'on the clock' I do. Thanks John. I didn't care during my first twenty years. But I always had an uneasy feeling when "everything I know about hydraulics I learned from the rules in NFPA 13". Unlike you, I was an English Major when I dropped out of college. Now this question is merely an after-hour curiosity, for entertainment purposes only if you will. That FM 2 1/2" K looks like C=.8 Allan, thanks. Brad On Feb 22, 2017 11:42 PM, "IPA" <[email protected]<mailto:[email protected]>> wrote: I believe I saved this info from this very forum but I have noted that FM global used to have k-factors for hydrants. Here are the values: 2 3/8" 134 2 1/2" 149 2 5/8" 164 On Wed, Feb 22, 2017 at 6:48 PM, John Denhardt <[email protected]<mailto:[email protected]>> wrote: Travis - well said Brad - who really cares if hydrants have a K factor? I know I don't. John August Denhardt, P.E. Strickland Fire Protection On Feb 22, 2017, at 8:45 PM, Travis Mack, SET <[email protected]<mailto:[email protected]>> wrote: Or just use the formula in NFPA 291- Standard for Hydrant Marking and flow tests or something like that... Q = 29.83*d^2*Cd*P^0.5 d = hydrant outlet diameter in inches C = the outlet coefficient (0.7, 0.8 or 0.9) P = Pitot pressure that is measured Not everything has to be extremely complicated and thought out to the nth degree. If you are really so inclined, why not spend the next few years solving for Pi to the 1,000,000th point. And guess what...... if you assign K to be 29.83*d^2*Cd........ you get 168 for your example. Wow...sometimes the simplest methods are the best. There is a true phenomenon that causes many people problems - paralysis through analysis. Travis Mack, SET MFP Design, LLC 2508 E Lodgepole Drive Gilbert, AZ 85298 480-505-9271<tel:(480)%20505-9271> fax: 866-430-6107<tel:(866)%20430-6107> email:[email protected]<mailto:email:[email protected]> http://www.mfpdesign.com https://www.facebook.com/pages/MFP-Design-LLC/92218417692 Send large files to us via: https://www.hightail.com/u/MFPDesign LinkedIn: https://www.linkedin.com/in/travismack On 2/22/2017 5:58 PM, Brad Casterline wrote: Say it's a 2.5" C=.9. I've tried to work this out a couple different ways: 1) a kind of long drawn out way, call it 'brad's way', and I get ~168. 2) a way i call the 'Bill Brooks back of napkin' way based on a few words he posted here a few years ago-- lightening fast, and i'll be damned if i dont get the same ~168! Basically, since K is the square feet area of the orifice he says 5*5*5.6=140, times (.9/.75) = 168. Anyway, if a hydrant butt has a K we could pretty quickly get the Q after the pitot'd P with Q=K*SQRT(P). thanks, Brad . _______________________________________________ Sprinklerforum mailing list [email protected]<mailto:[email protected]> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected]<mailto:[email protected]> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected]<mailto:[email protected]> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected]<mailto:[email protected]> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
_______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
