Tony: I believe NFPA 20 2003 and 2007 limit the use of a main pressure relief valve for use with a diesel pump and/or in combination with a variable speed drive. I don't believe the relief valve is allowed with an electric pump just to chop off the high end of the pressure curve.
Bobby McCullough -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of A.P.Silva Sent: Wednesday, March 14, 2007 1:37 AM To: [email protected] Subject: RE: pump tricks This is an old thread, but I'm working on two projects, a six storey and 9 storey with fire pumps and it got me thinking (not an easy feat). Most times, the problem is not when you have a large flow through the sprinklers or hose stations. It is when the flow is small or at churn pressure. When the flow is large, the pressure has dropped down below 175 psi. When the flow is small you don't need the extra pressure. So if you install a pressure relief valve set at say 160 psi, you shouldn't need the XH pipe, fittings and pressure reducing valves. I might be wrong, but I'm thinking the pressure relief valve must be costing less than a pressure reducing valve. Any thoughts? Tony -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Todd Williams - work Sent: February 7, 2007 7:22 AM To: [email protected] Subject: pump tricks I seem to be running into several situations lately where there is a very fine balancing act between meeting the 100 psi at the top outlet of the standpipe and not exceeding 175 psi at the base of the riser. (6 story hotels are a good example) Does anybody have any good ideas they'd care to share on making these work? I'd like to limit the use of extra-heavy pipe and fitting (especially larger sizes) and PRVs. I have several tricks up my sleeve, but I'm running out of sleeves. Todd Todd G. Williams, PE Fire Protection Design/Consulting Stonington, Connecticut 860-535-2080 www.fpdc.com _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum
