http://www.mail-archive.com/sprinklerforum%40lists.firesprinkler.org/msg4216 9.html
James, here is link to archived post I made last July. I changed the English version to show how I got ~195 gpm. I used the Article Roland mentioned as a way forward, and for checking (and correcting) my thinking as I went along. In the text of the post is some brief 'instructions' for zeroing in on the estimated flow. I know it appears unorthodox, but all I did is break the Darcy-Weisbach fl formula down to its simplest form (using ft, ft^2, ft^3, sec, and sec^2). In order for me to be able to understand anything it has to be in a form where it could not be any simpler. If you or any other Forumite wants, I could send the spreadsheet directly to you. NOTE- it has not been QC'd by anyone other than myself, nor have I gotten any feedback whatsoever, but I did post my progress, mistakes, thinking, etc., here, as I went. Brad -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of Brad Casterline Sent: Tuesday, April 26, 2016 12:49 PM To: [email protected] Subject: RE: Forward Flow for a Backflow Preventer According to my spread sheet you could get ~195 GPM, based on 10 ft of 1.25" pipe, 1 angle valve, 1 tee (connection to riser) 1 ell, and 1 45. This would be using the main drain for the forward flow. Brad On Apr 26, 2016 12:23 PM, "Matt Grise" <[email protected]> wrote: > How low can you go with a hose monster with a 1.25" insert (don't have my > chart handy) > > Matt Grisé PE*, LEED AP, NICET II > Sales Engineer > Alliance Fire Protection > 130 w 9th Ave. > North Kansas City, MO 64116 > > *Licensed in KS & MO > > 913.888.0647 ph > 913.888.0618 f > 913.526.7443 cell > www. AFPsprink.com > > > > -----Original Message----- > From: Sprinklerforum [mailto: > [email protected]] On Behalf Of James > Crawford > Sent: Tuesday, April 26, 2016 12:16 PM > To: [email protected] > Subject: Forward Flow for a Backflow Preventer > > I know this has been discussed but can't seem to find it. > > > > NFPA #13 (2013) 8.17.4.6.1 Means shall be provided downstream of all > backflow prevention valves for flow tests at system demand. > > > > We have a small office system, system demand 160 gpm, we have 100 psi > static pressure, the system has a 2 ½" riser so a 1 ¼" drain, how much > water can we get out of an 1 ¼" drain? > > > > Is there anything out there to help determine the size and or number of > outlets required to forward flow at different system demands? > > > > > > Thank you > > > > > > James Crawford > > Phaser Fire Protection Ltd. > > Phone 604-888-0318 > > Fax 604-888-4732 > > Cel 604-790-0938 > > Email [email protected] > > > > _______________________________________________ > 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
