Lets look at what FM Global has to say. According to FM Global’s minimum approval standards for these valves, "Approval Standard for Angle and Straightaway Hose Valves, Class Number 1521/1522 , December 2014”
"4.11 Friction Loss Test – Traditional Hose Valves Only 4.11.1 Requirement The valve shall be designed so that the obstruction in the waterway is minimal. For valves found to be non- compliant with Sections 3.2.3 and/or 3.2.4, friction loss testing is necessary. The valve will be tested in the full open position, and the friction loss through the valve will be measured at a flow rate that produces a fluid velocity of 20 ft/sec (6.1 m/sec) in Schedule 40 steel pipe of the same nominal diameter as the valve. The measured friction loss shall be less than 10 psi (69 kPa)." The “sections 3.2.3 and/or 3.2.4” in the text refers to physical seat lift dimensions in the valve. So FM does not took at pressure loss if the valve guts meet their internal dimension numbers. The standard does not refer to angle versus straight in regard to pressure loss. Both patterns must meet the same standard. I believe that 20 ft/sec in 2.5” schd. 40 pipe comes to 298 GPM at 10 psi drop, which comes to a K near 94. Figuring FM approval is “better than your average bear.”, you might not want to use a K larger than 94. That 94 K would lose about 7 psi at 250 gpm. Allan Seidel St. Louis, MO > On Feb 19, 2017, at 12:44 PM, Brad Casterline <[email protected]> wrote: > > Of course! > I know this is unorthodox thinking, especially for an NFPA 14 maestro. > But I figured out quite a few years ago how to get not only K, but the Q and > P that goes with it for a flowing outlet with only two pieces of information; > the nominal diameter and the coefficient of discharge. > And after the twists and turns and showing off and stepping in it this > weekend I wanted to take my best shot at being the anybody with a decent K > for a 2.5 inch hose valve, as Vince asked. > So "In the same way as a nominal 1/2" sprinkler..." > K=113.85, if the C of D is .61, > final answer. > > Thanks for hollering back, I was getting lonely out here, > > Brad > > On Feb 19, 2017 11:13 AM, "Steve Leyton" <[email protected] > <mailto:[email protected]>> wrote: > Of course, that should have been GPM and not PSI. > > > Steve > > > -------- Original message -------- > From: Steve Leyton <[email protected] > <mailto:[email protected]>> > Date: 2/19/17 8:44 AM (GMT-08:00) > To: [email protected] > <mailto:[email protected]>, Vince Sabolik > <[email protected] <mailto:[email protected]>> > Subject: RE: K for a Hose Valve > > Awesome. So the "nominal" flow at 100 PSI will be 1,138.5 PSI? > > Maybe we need to change the hydraulic design method in the standard. > > Steve L. > > > -------- Original message -------- > From: Brad Casterline <[email protected] <mailto:[email protected]>> > Date: 2/19/17 2:09 AM (GMT-08:00) > To: Vince Sabolik <[email protected] <mailto:[email protected]>>, > [email protected] > <mailto:[email protected]> > Subject: Re: K for a 2½" Hose Valve > > K=113.85 > > In the same way that a nominal 1/2" sprinkler with a Coefficient of Discharge > of .75 has a K=5.6, a nominal 2.5" hose valve with a Coefficient of Discharge > of .61 has a K=113.85. > > Brad > > On Feb 17, 2017 8:28 AM, "Vince Sabolik" <[email protected] > <mailto:[email protected]>> wrote: > Good morning, everyone... > > Does anybody have a decent K Factor for a 2½" hose valve? > > Thanks! Vince > <20914 x WTFP Logo NEW1.jpg> > 11351 Pearl Road / Suite 101 > Strongsville, Ohio 44136 > Phone 440 238-4800 <tel:(440)%20238-4800> Fax 440 238-4876 > <tel:(440)%20238-4876> Cell 440 724-7601 <tel:(440)%20724-7601> > > Vince Sabolik > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > <mailto:[email protected]> > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > <http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org> > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > <mailto:[email protected]> > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > <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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