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
