Thanks Roland and Travis. No wonder I felt squeamish about this. I don't have a lot of experience with 'going up and to the left' of the LH thru EH curves. Good eye on the listing Travis-- the one I just looked at shows SR for 200F at 20 x 20!!!
Brad -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of Travis Mack Sent: Thursday, April 30, 2015 9:51 AM To: [email protected] Subject: Re: QR Reduction and single points on the Density/Area Curves But don't you have to go by the data sheets for the sprinklers? It only lists 20x20 at 40 gpm for light hazard. I don't see where the data sheet says I can apply a lower flow for 20x20 spacing Travis Mack, SET MFP Design, LLC 2508 E Lodgepole Drive Gilbert, AZ 85298 480-505-9271 fax: 866-430-6107 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 On 4/30/2015 7:46 AM, Roland Huggins wrote: > Since you picked 2000 sf based on 5 EC sprinklers, you can NOT reduce it due to the 5 sprinkler minimum. SO you go back to your 3,000 sf at .06, reduce it to a minimum of 1800sf but exceed it since you're back at 2000 sf due to the perfect 20 x 20 of your EC coverage and 5 sprinkler minimum. Cutting it back to 18 X 18 would not meet the 1800 so to get a perfect score, back to the area/density curve and pick 2700 sf at .076. > > Roland > > > Roland Huggins, PE - VP Engineering > American Fire Sprinkler Assn. --- Fire Sprinklers Saves Lives > Dallas, TX > http://www.firesprinkler.org <http://www.firesprinkler.org/> > > > > > >> On Apr 30, 2015, at 6:39 AM, Brad Casterline <[email protected]> wrote: >> >> Dear Forum, >> >> >> >> I would appreciate feedback on the technical (or moral) correctness of the >> following scenario: >> >> >> >> NFPA 13 (2010 or 2013), Light Hazard, Ceiling smooth and flat at 10'-0" AFF. >> >> Sprinklers= QR, EC, 200F, K=11.2 at 20' x 20'. >> >> >> >> Choose .07/3000 for starting point from L.H. curve. Apply Q.R. Reduction-- >> 3000 x .6 = 1800 ft^2. >> >> Length of operating area = 1.2 x SQRT(1800) = 50.91 ft., / 20 = 3 hds/line. >> 1800/400= 6 hds operating. >> >> Q=400 x .07 = 28 GPM. P=(28/11.2)^2 = 6.25 PSI raise to EHP= 7 PSI. >> >> >> >> Since (5) is the minimum number of operating heads for Density/Area, is it >> OK to 'choose' the density based on 3000 ft^2, or would it be more righteous >> to 'use' the density based on 5 x 400 = 2000 ft^2, .09, then reduce the >> operating area to 2000 x .6 = 1200 ft^2? >> >> >> >> 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 _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
