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]> 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]> 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]> 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]> >>> 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 85298480-505-9271 <(480)%20505-9271> >>> fax: 866-430-6107 <(866)%20430-6107>email:[email protected] >>> http://www.mfpdesign.comhttps://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 >>> [email protected]http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org >>> >>> >>> _______________________________________________ >>> Sprinklerforum mailing list >>> [email protected] >>> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-f >>> iresprinkler.org >>> >>> >>> _______________________________________________ >>> Sprinklerforum mailing list >>> [email protected] >>> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-f >>> iresprinkler.org >>> >>> >> >> _______________________________________________ >> Sprinklerforum mailing list >> [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
