I'd make sure that an air make up device is used, with the typical maintenance bypass.
Bruce > On Mar 1, 2017, at 06:18, Mike Stossel <[email protected]> wrote: > > Brad is actually trying to help me off forum. It is definitely a difficult > calculation to run and way beyond me. At least if it had a dry valve I could > run an FDT calculation, but it has nothing. It is a closed system with an > air compressor only. A 2 ½” dump valve is located at each FDC with a gauge. > When the fire department arrives they open the dump valve and when it hits > zero starts pressurizing the temporary standpipe. The air in the system is > just supervisory. You have low pressure and high pressure alarms attached > just like a dry valve, but minus the dry valve. The air is just to make sure > the system is always solid for the fire department. If someone should tamper > with it or break something the alarm will notify that a repair is needed. > > Mike Stossel SET > <image001.png> > 36 Barren Road > East Stroudsburg, PA 18302 > Office: 973-670-2627 > [email protected] > > From: Sprinklerforum [mailto:[email protected]] > On Behalf Of Tom Duross > Sent: Wednesday, March 1, 2017 9:07 AM > To: [email protected] > Subject: RE: Air Relief Time > > Sounds like an automatic dry standpipe off a low differential dry valve but > you’re not concerned about water delivery time or even water pushing out the > air? Just a 2 ½” outlet at the top? > Where’s Brad? > > From: Sprinklerforum [mailto:[email protected]] > On Behalf Of Mike Stossel > Sent: Wednesday, March 01, 2017 9:01 AM > To: [email protected] > Subject: RE: Air Relief Time > > The standing air pressure is a minimum of 13psi and a maximum of 18psi. The > gauge located at the FDC must read zero within 3 minutes of full open. > Compressor is connected and running. Four 4” stacks top of stack is 70’0”. > > Thanks, > > Mike Stossel SET > <image004.png> > 36 Barren Road > East Stroudsburg, PA 18302 > Office: 973-670-2627 > [email protected] > > From: Sprinklerforum [mailto:[email protected]] > On Behalf Of Tom Duross > Sent: Wednesday, March 1, 2017 7:54 AM > To: [email protected] > Subject: RE: Air Relief Time > > NYC has a requirement for construction standpipes in all high-rises to be > pressurized and monitored with a placard indicating required FDC pressures > for required flows at each floor. Boston adopted this last year. Roadway > standpipes are required to be timed for water delivery but are empty and have > automatic air vents at the FDV’s. What’s the application requiring exhaust > of standing air pressure? Is there a compressor connected and running? > Horizontal or vertical installation? > TD > > Sidestep the issue. If you can, pull a slight vacuum on the standpipe instead > of pressurizing it. > > > On Feb 28, 2017, at 7:17 AM, Mike Stossel <[email protected]> wrote: > > I am trying to calculate the time it will take for a 2-1/2” hose valve to > relieve a standpipe system of air. I am designing a temporary standpipe > system in NYC and the requirement is to fill the entire system with air and a > single 2-1/2” hose valve needs to relieve the pressure within 3 minutes or a > second will need to be added. My total system volume will be 1902 gallons > and the staring air pressure will be at 18psi. Does anyone know of a way to > calculate this? > > Thanks for the help. > > Mike Stossel SET > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
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