Consider installing the check valve vertically. Should help with your concerns, since gravity would help keep the clapper shut. I would think the longer the vertical pipe drop is on top of the check, the more likely it is to hold, so you may consider that when laying out your riser room.
To answer your original question, I believe NFPA 13 doesn't explicitly require a drain at the low point between the check valve and FDC. It does require a ball drip between the check and FDC in areas subject to freezing, but doesn't specifically say it has to be installed at the low point. It does require an aux. drain on the system side of the check, if that is trapped. This is an issue that is almost never dealt with in the real world. Kind of like hydrostatically testing the piping from the FDC to the check. We have literally shop vac'd or pumped the water out if the check leaks on these. - Skyler On Wed, Mar 10, 2021 at 10:17 AM Dewayne Martinez via Sprinklerforum < [email protected]> wrote: > I see a trend starting in our area where the architect is specifying a > remote free standing FDC without a valve pit when the check valve can be > placed inside the building. Upon talking to my field superintendent he was > concerned that some check valves let multiple gallons of water through > whenever a system is drained and refilled and that the remote pipe may > eventually fill up and freeze. We were toying with the idea of installing > a return bend in the FDC pipe downstream of the check before it leaves the > building to help prevent this. A ball valve would be installed between > the return bend and check to drain out the pipe. Anyone else have insight > on this? > > Thank you, > > Dewayne Martinez > Fire Protection Design Manager > > TOTAL Mechanical > Building Integrity > > W234 N2830 Paul Rd. > Pewaukee, WI 53072 > [email protected] > Ph: 262-522-7110 > Cell: 414-406-5208 > http://www.total-mechanical.com/ > _______________________________________________ > Sprinklerforum mailing list > [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
