If it's above 30' but not a high-rise, why the automatic system? The standpipe can definitely be manual, which will take the fire pump issue out of the conversation.
To the basis of design - based on what I know about friction loss through hose packs and accessory fittings in a typical attack configuration, 65 PSI at the outlet leaves you about 10-20 at the tip if you're using 1½" packs, a little more if they're 1¾". If you've got 1¼" hoses, then you have to pump it no matter what so it's effectively a manual at that point. I'm not you, but if I was I'd say it's 100 or bust. If you're inclined to grant relief for whatever reason, do so based on the fact that if it's not a high-rise, they can do an over-arching design based on a manual, i.e. calc' it from the FDC and prove 100 PSI minimum at the two most remote outlets + 250 GPM for each additional standpipe. 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 Leyton Protection Design & Consulting San Diego, CA From: Sprinklerforum [mailto:[email protected]] On Behalf Of Thomas Reinhardt Sent: Wednesday, November 01, 2017 12:28 PM To: [email protected] Subject: RE: Standpipe Pressure Question. The highest story is above 30 feet. Thus are adopted IFC chapter 9 section 905.3.1 apply. Standpipes to be automatic wet. Thanks From: Sprinklerforum [mailto:[email protected]] On Behalf Of Steve Leyton Sent: Wednesday, November 01, 2017 2:22 PM To: [email protected]<mailto:[email protected]> Subject: RE: Standpipe Pressure Question. How many stories is the building? I'm going the same way as Nick did with his question. Yes, 100 PSI came in 1993. SML From: Sprinklerforum [mailto:[email protected]] On Behalf Of Don Casey Sent: Wednesday, November 01, 2017 12:21 PM To: [email protected]<mailto:[email protected]> Subject: RE: Standpipe Pressure Question. When did 14 bring in the 100psi requirement? 93? (or is my imagination running in the wrong direction). If the building was constructed prior to the 100psi requirement, is there an argument that you're maintaining the level of performance of the originally designed system? From: Sprinklerforum [mailto:[email protected]] On Behalf Of Thomas Reinhardt Sent: 2017/11/01 3:09 PM To: [email protected]<mailto:[email protected]> Subject: Standpipe Pressure Question. Question for the forum. I have a complete renovation of a school. They are required to have 3 standpipes installed. The designers approached me and asked if one of the standpipes could have a reduced pressure. The reason is because then they would have to upgrade the electrical power to the pump. This in turn would make them upgrade the power for the backup generator. This would create an economic problem for the school district. In researching NFPA 14. I found that the minimum residual pressure at 2.5 in. should be 100psi for each standpipe. Am I interpreting this correct. They asked that 1 standpipe be only 65psi (doesn't sound correct). NFPA 14 says that standpipes shall provide 250 gallons. All standpipie hose connections to be class 1 systems. Am I missing something. Thanks Tom Reinhardt Fire Inspector/Plan Reviewer Skokie Fire Department 7424 Niles Center Road Skokie, IL 60077 Office: 847-982-5342 [email protected]<mailto:[email protected]>
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