Thanks George. I know of at least two teachers whom would agree with you. But I never underestimate a Sprink, especially a student Sprink. I did sprinkler calcs for 18 years and was still liable to say "gravity? what's gravity got to do with sprinkler calcs"? Since the answer is "only everything, but it's nowhere in 13", I see the type of understanding you three might advocate as ridiculous, to say the least. Plus, this Forum is bigger than a contractor's office, or a classroom full of contractor's sons who would rather be anywhere else.
-----Original Message----- From: George Church [mailto:[email protected]] Sent: Tuesday, June 11, 2013 12:05 PM To: [email protected] Subject: Re: adjusting the K-Factor with our bare hands I'd be concerned that you have completely muddled up kfactors for someone who no longer looks at it as the standard and industry practices do. But why listen to us warning about sending novices out with the wrong viewpoint? Sent from my iPhone On Jun 11, 2013, at 7:52 AM, "Brad Casterline" <[email protected]> wrote: > From NFPA 13-2007, 22.4.4.5.1, we are required to, among other things, > adjust the K-Factor. > > Using the Hazen-Williams friction formula, 62.4 lb/ft3 / 144 in2 = .433 > lb/in2/ft(h). > > If we have an AF solution at 65.5 lb/ft3, / 144 = .455 lb/in2/ft(h). > > If K=5.6, and we assume P=7 PSI.: > > 7/.433=16.166 ft(h). 7/.455=15.385 ft(h).* > > 15.385/16.166=.952. sqrt(.952)=.976, x 5.6 = 5.46. > > There is a chart in 13 showing a 50% glycerin solution at about -10F > weighing about 15% more than 100% water: 62.4 x 1.15 = 71.76. > 71.76/144=.498. 7/.498=14.056 ft(h). 14.056/16.166=.869. sqrt(.869)=.932, x > 5.6 = 5.22. > > If I had to fab the pipe today and formalize the submittal tomorrow (after > googling centipoises for several hours) I would calc it like it was 'all > wet', using K=5.22. > > * converting PSI to feet of head(h) it is seen that the denser the solution, > the 'shorter' it is. Since v=sqrt(2gh), the shorter it is the slower it is. > Making the adjustment based on "h", we have to take the square root of the > ratio, i.e., (K=Q/sqrtP). If adjusted based on velocity we would use the > ratio itself (square feet=cubic feet per second divided by feet per second): > sqrt(2*32.2*16.166)=32.266 ft/sec. > > sqrt(2*32.2*15.385)=31.477 ft/sec. > > 31.477/32.266=.976. > > > > The above is simply the type of thing I enjoy doing and like to share, > hoping it will cause no harm, to be taken or left as one sees fit. > > > > thanks, > > > > Brad Casterline, NICET IV > > Fire Protection Division > > > > FSC, Inc. > > P: 913-722-3473 > > [email protected] > > www.fsc-inc.com > > > > Engineering Solutions for the Built Environment > > > > _______________________________________________ > 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 _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
