In the case I mentioned, the local FD agreed with me that creating a two-zone system for 15 PSI was of no value when all of the components were not just rated but listed for the working pressure. I’m a big proponent of keeping it as simple as possible. Why would I want to use two pumps (or complements of pumps if redundancy is required) when I can use one? Why create two zones (including a second complement of FDC’s) if I don’t have to? Simplification and reliability are paramount; I prefer the use of single point pressure reduction over master PRV’s (as do just about all fire departments) but that approach is measurably more expensive.
Back story: pressure reducing hose and control valves are listed for 400-500 PSI, so 350 is just a number that has been carried over from much older versions of the standard. When we tried to completely remove the pressure limit from the standard in the early 2000’s, we got hit with amending motions on the floor of two code hearings. The major objection came from the pump people because the standard still required a separate pump for each zone at that time. The TC lost the first one so we came up with the express main definition and the master PRV prescriptives and got it passed into the 2007 edition for the first time. I do not see any reason why there should be a pressure limit on any part of a standpipe system. There is even a 600 PSI FDC available from Dixon. This is absolutely my opinion only. However, as chair of the TC, I definitely have an agenda and this will be tasked in our 2019 Pre-First Draft meeting. SL From: Sprinklerforum [mailto:[email protected]] On Behalf Of Daniel Wilder Sent: Wednesday, August 03, 2016 5:27 AM To: [email protected] Subject: RE: HIGH RISE BUILDING Are we talking Standpipe/Express Mains or the actual sprinkler system itself? Not sure what edition you are working from but 7.2.1 allows up to 350 PSI for any point in the system and over 350 PSI for express mains (7.2.2/7.2.2.1) out of NFPA 14 2010 up to the current 2016. The Sprinkler Age Edition had a lot of good info as well that may be of use for your AHJ. http://reader.mediawiremobile.com/AFSA/issues/105223/viewer?page=17 Dan From: Sprinklerforum [mailto:[email protected]] On Behalf Of Dewayne Martinez Sent: Tuesday, August 2, 2016 5:44 PM To: [email protected]<mailto:[email protected]> Subject: Re: HIGH RISE BUILDING So when it says "sprinkler pipe maximum working pressure" I can ignore it? How do I get this past the reviewer? Sent from my iPhone On Aug 2, 2016, at 7:25 PM, Steve Leyton <[email protected]<mailto:[email protected]>> wrote: Okay, time to go outside the box -schedule 10 and 40 piping isn’t required to be listed … ASTM A53B black steel schedule 40 has is rated for working pressures of 430 PSI (4”) and 696 PSI (6”). And those are with welded joints. Vic has what … 700 PSI working pressure for the Style 77 (or something like that)? Far and away the hardest equipment to find is valves that act directly on the maximum discharge pressure. SL From: Sprinklerforum [mailto:[email protected]] On Behalf Of Dewayne Martinez Sent: Tuesday, August 02, 2016 5:17 PM To: [email protected]<mailto:[email protected]> Subject: Re: HIGH RISE BUILDING Thanks for the information. What did you do for the 300psi limit on pipe? Sent from my iPhone On Aug 2, 2016, at 6:36 PM, Steve Leyton <[email protected]<mailto:[email protected]>> wrote: We made 360 total head at churn if I recall correctly. Everything downstream UL (USA) listed for fire – had to hunt down check and butterfly valves from Victaulic rated for 365. Here in CA all high-rises have tanks, so PSH of about 7’ + pump rating at max churn. Big pump yes, but not a monster as it was only a 750. We had three or four stairs in the basement and podium levels, so designed to a couple of points on the curve. We’ve done foam underwing systems for Navy and Marine Corp hangars with .17/15,000 flowing concurrently at the roof with total demand of 4,500-5,000 GPM. Now THOSE are big pumps. SL From: Sprinklerforum [mailto:[email protected]] On Behalf Of Tom Duross Sent: Tuesday, August 02, 2016 4:21 PM To: [email protected]<mailto:[email protected]> Subject: RE: HIGH RISE BUILDING Must have been one hell of a pump. There is no height limit in latest editions of NFPA 14. Standpipes that directly supply hose connections are limited to 350 PSI (stay tuned for 2019 cycle on that one) but there is no height or pressure limit on express mains that serve upper zones. Our firm designed a 545’ single zone system for a tower here in San Diego. The foregoing is my opinion only and is not intended to represent the NFPA 14 Technical Committee, nor serve as an interpretation of the standard. Steve L. _______________________________________________ Sprinklerforum mailing list [email protected]<mailto:[email protected]> 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
_______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
