And if you dig around the archives at AFSA virtually (or buy Roland lunch) you'll find a dissertation on why the velocity shouldn't be limited- it's because when you are whizzing that much water the friction loss, as Thom pointed out, is so excessive that the loss quickly adds up and you run outa water supply. UNLESS you have a heckuva water supply (again, as Thom normally has unless water delivery is via high velocity avalanche) in which case there's no reason you cannot have high velocities....except that if the fire doesn't grow in the shape we assume it will, or for some other reason one extra head opens on a branch line that you didn't figure on, and the delivered density goes kaput.
FM was 20 fps, thought they might still have the "acme grinnell rule" for lines less than 2" in diameter. Anytime I get flack about velocity, I sic Roland on em. I'm surprised he didn't jump back on this favorite soapbox of his. George Church Rowe Sprinkler -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Thom McMahon Sent: Tuesday, January 09, 2007 6:49 PM To: [email protected] Subject: Re: max velocity Because we use Hazen Williams for fire sprinkler design, this formula already creates a pressure penalty for excessive velocity, therefore no limit is put on fire sprinkler system velocities. Just as a side note Backflow preventors are tested and usually listed at 10 Fps, if your exceeding the flow limits of the backflow preventor you can damage it in full forward flow testing. Thom McMahon Firetech, Inc. 2560 Copper Ridge Dr Steamboat Springs, CO 80488-2136 Tel: 970-879-7952 Fax: 970-879-7926 ----- Original Message ----- From: "Ivan Cabrera" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Tuesday, January 09, 2007 3:57 PM Subject: max velocity _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum
