Since other than NFPA 15 systems, virtually NO ONE applies Pv so why add the additional complexity. This is especially true with Pt being a MORE conservative approach.
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 24, 2015, at 8:11 AM, Brad Casterline <[email protected]> wrote: > > Working pressure is defined, and used in a few places in the text. Operating > Pressure is not defined but is used extensively and is obviously meant to be > used to calculate the discharge rate of sprinkler heads. According to > Webster's, Working and Operating are synonymous, but this results in a > problem where ~minimum operating pressure (for sprinklers) shall be 7 psi~, > due to the "2nd head phenomena", where the Pv between the end and 2nd heads > exceeds the Pf, making Pn at the 2nd head less than 7 psi. Since only the Pn > produces flow at the 2nd head we are "allowed" to subtract Pv. > > > > So the suggestion for the definition of Operating Pressure regarding > sprinkler discharge is to specify minimum Pn shall be 7 psi. > > > > Just wanted to get that off my chest. > > > > 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
