As I understand - the control valve is so you can shut down the individual system for maintenance. The check valve is so you don't have to shut them all down in order to drain the standpipe (and risk leaving a valve closed).
The NFPA 13 annex has a couple of diagrams indicating suggested layouts. The location of the pressure reducing valve depends on how much water pressure the fire department wants at the hose connection. If the FD wants the pressure limited at the hose connection, then put it before. If the FD does not mind or prefers extra pressure, then put it after. Be sure to check NFPA 14 requirements regarding PRV's that serve hose connections. Matt From: Sprinklerforum [mailto:[email protected]] On Behalf Of Colin Carew (Cambridge) Sent: Wednesday, August 30, 2017 4:10 PM To: [email protected] Subject: NFPA 13 8.17.5.2.2(1) Wondering , what is reason behind the Control valve and check valve of the same size at the connection is required per 13 8.17.5.2.2 (1) I have a connection , where I connect to the standpipe with 2.5" pipe and then to a PRV control valve , then after I feed a standard hose valve and reduce down to 2" for my sprinkler control valve assembly . Thanks . Colin Carew
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