I am nothing if not tenacious. I've been advocating the real simplicity here for ~five years. What could possibly be simpler than using feet and seconds ONLY do any and all things sprinkler hydraulic? This includes calculating the impeller diameter of a pump, given the rated psi and rpm only. For 22 years I have been able to remember "square feet times feet per second equals cubic feet per second", but I can't remember what comes after "28 point...", even though I just looked at it. And being able to do everything with feet and seconds make metric conversions easier and less prone to translation errors. Still, it is so subtle as to not be accepted, but I'll never give up pushing it a few times a year. On Oct 1, 2016 2:39 PM, "Brad Casterline" <[email protected]> wrote:
> So Ken, I'll ask you too, > What GPM do you come up with? > On Oct 1, 2016 2:28 PM, "Parsley Consulting" <[email protected]> > wrote: > >> Travis, >> that's the most worthwhile advice I've read on this forum in some >> time. Just keep it as simple as possible. The more complex one makes the >> math the greater the opportunity for a digit, a decimal, a square, a square >> root, take your pick, to applied incorrectly, and thus skew the results to >> where they're no longer relevant. >> >> Look at equation 4.9.3 in -291. It's exactly the same equation you >> quoted. Very simple. >> >> 29.84 * c * d² * √p >> >> >> Of course, I suppose the charts in -291 could be helpful if you >> didn't need the results calculated out to tenths of a gallon. They're all >> the result of the same equation with a C = 1.00 so converting to a >> different hydrant outlet coefficient is relatively easy. >> >> See disclaimer below. >> sincerely, >> >> *Ken Wagoner, SET Parsley Consulting* >> >> >> >> >> >> >> >> >> * 350 West 9th Avenue, Suite 206 Escondido, California 92025 Phone >> 760-745-6181 <760-745-6181> Visit our website >> <http://www.parsleyconsulting.com/> IMPORTANT NOTICE: This correspondence >> is not a Formal Interpretation issued pursuant to NFPA Regulations. Any >> opinion expressed is the personal opinion of the author and does not >> necessarily represent the official position of the NFPA or its Technical >> Committees. In addition, this correspondence is neither intended, nor >> should it be relied upon, to provide professional consultation or services >> It should be noted that the above is my opinion as a member of the NFPA >> Installation of Private Fire Service Mains and their Appurtenances >> Committee in accordance with the NFPA Regulations Governing Committee >> Projects and should therefore not be considered, nor relied upon, as the >> official position of the NFPA or its Committees * >> >> >> On 10/01/2016 11:51 AM, Travis Mack wrote: >> >> Follow the formula in the standards. >> >> 29.83 x hydrant coefficient x pumper modification x diameter x diameter x >> sqrt (pitot pressure) >> >> Keep it all simple. No need to overcomplicate everything. >> >> There are even several apps to put in your phone to do this stuff. >> Keep it all simple. >> >> Travis Mack, SET >> MFP Design, LLC >> "Follow" us on Facebook: https://www.facebook.com/pages/MFP-Design-LLC/ >> 92218417692 >> Send large files to MFP Design via: >> https://www.hightail.com/u/MFPDesign >> >> Sent from my iPhone >> >> On Oct 1, 2016, at 11:35 AM, Brad Casterline <[email protected]> >> wrote: >> >> My pleasure Jeff, thanks for saying. >> On Oct 1, 2016 1:32 PM, "Jeff Normand" <[email protected]> wrote: >> >>> Thanks for sharing Brad. >>> >>> On Sat, Oct 1, 2016 at 1:28 PM, Brad Casterline <[email protected]> >>> wrote: >>> >>>> Say it's a 2.5" butt (small, smooth and well rounded my personal >>>> favorite) so C=.9. >>>> >>>> ((2.5/24) ^2) * PI = .034 ft^2. >>>> .034 * .9 = .0307 ft^2. >>>> >>>> Say pitot = 30 PSI. >>>> 30/.433=69.284 ft (h). >>>> v=(2gh)^.5=(2*32.2*69.284)^.5=69.8 ft/sec. >>>> .0307 ft^2 * 69.8 ft/sec = 2.05 ft^3/sec, * 7.48 * 60 = 920 GPM. >>>> >>>> That's not too shabby! >>>> >>>> Brad >>>> >>>> _______________________________________________ >>>> 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 >> [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 >> >>
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