NFPA 20 does not allow. See 4.7.7.2
4.7.7* Maximum Pressure for Centrifugal Pumps. 4.7.7.1 The net pump shutoff (churn) pressure plus the maximum static suction pressure, adjusted for elevation, shall not exceed the pressure for which the system components are rated. 4.7.7.2* Pressure relief valves and pressure regulating devices in the fire pump installation shall not be used as a means to meet the requirements of 4.7.7.1. Peter Schwab VP of Purchasing & Engineering Technologies Wayne Automatic Fire Sprinklers Inc. 222 Capitol Court Ocoee, Fl 34761 Mobile: (407) 468-8248 Direct: (407) 877-5570 Fax: (407) 656-8026 www.waynefire.com We're hiring great people at all of our locations! Please check out our website for the details! -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of John Denhardt Sent: Tuesday, May 20, 2014 1:03 PM To: 'Steve Leyton'; Martinez, Dewayne; [email protected] Subject: RE: Pressure reducing valve on fire pump Is a main relief valve allowed in this case - see NFPA 20. Most likely not! John -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of Steve Leyton Sent: Tuesday, May 20, 2014 12:13 PM To: Martinez, Dewayne; [email protected] Subject: RE: Pressure reducing valve on fire pump Dewayne: Why a reducing valve instead of a relief valve? If the excess pressure is at churn only, then a relief valve would be the ticket as it only occurs in a no-flow condition. This would mitigate Pete's concerns about redundancy as prescribed in NFPA 14. SML -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of Martinez, Dewayne Sent: Tuesday, May 20, 2014 5:20 AM To: [email protected] Subject: Pressure reducing valve on fire pump We have a situation where we have a pump that produces more than 175psi at churn. Can we put in a main pressure reducing valve after the pump discharge to bring it all down to 175psi or do we need one for each system? Thanks, Dewayne _______________________________________________ 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
