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 [400dpiLogoCropped] 36 Barren Road East Stroudsburg, PA 18302 Office: 973-670-2627 [email protected]<mailto:[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]<mailto:[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 [400dpiLogoCropped] 36 Barren Road East Stroudsburg, PA 18302 Office: 973-670-2627 [email protected]<mailto:[email protected]> From: Sprinklerforum [mailto:[email protected]] On Behalf Of Tom Duross Sent: Wednesday, March 1, 2017 7:54 AM To: [email protected]<mailto:[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]<mailto:[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
