Valve, Check, Flow Switch Req'd on Standpipe?

8/4/2020

We have a 5-story building with wet manual standpipes in three stairwells. A single FDC connects to the end of a manifold in the riser room that has a 4-inch dry system, a 4-inch wet sprinkler, and a 6-inch riser that supplies the three standpipes. Each standpipe has a separate isolation valve at its stair tower. One of the standpipes is a combination standpipe/riser with sprinkler floor control valves for levels 2-5.

Regarding the 6-inch standpipe riser off of the manifold:

Is a control valve required, or allowed?

Is a check valve required?

Is a flow switch required, or recommended?

This project is under NFPA 14-2013 Edition. Thanks.

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3 Comments

Dan Wilder

8/4/2020 08:50:50 am

References are to NFPA 14 -19' Ed. but it looks the same in the 13' edition.

Yes, a control valve is required as this is considered a standpipe regardless of if it feeds sprinkler systems or not. Figure A.7.1(a) has a good single line diagram that mimics your described setup (without the fire pump).

Check valve for the individual standpipes is not required, the only locations that require a check valve are the Connection to Water Supply (6.3.1), where floor control assemblies are for the sprinkler systems (6.3.5), and the FDC (6.4.2). The only exception would be if there is interconnection at more than one location (top and bottom) per 7.5.3.

Waterflow switches are not required per standpipe but are required per standpipe "system" per 5.6.1, (A.7.1(a) has this detailed, again, without the pump) to indicate either tampering of the hose valves or a break in the system. I'm not an advocate for putting flow switches on ever individual standpipe.

Patrick Turner

8/4/2020 01:03:53 pm

This can be found in either NFPA 13 or NFPA 14:

Per NFPA 14, 2016 Edition, Section 6.3.2 (not sure what the exact 2019 Edition Section Number is at this time but it is in there): "Valves shall be provided on all standpipes...to allow isolation of a standpipe without interrupting the supply to other standpipes from the same source of supply".

Per NFPA 14, 2016 Edition, Section 6.3.5.1: "Each connection from a standpipe that is part of a combined system to a sprinkler system shall have an individual control valve and check valve". See Figures A.6.3.5(a) and A6.3.5(b) of NFPA 14, 2016 Edition for details of Acceptable Piping Arrangements for Combined Sprinkler/Standpipe System.

Per NFPA 13, 2016 Edition, Section 8.17.5.2.2(1): "Each connection from a standpipe that is part of a combined system to a sprinkler system shall have an individual control valve and check valve of the same size as the connection".

Per NFPA 13, 2016 Edition Section 8.17.5.2.2(3):"Each combined sprinkler and standpipe riser shall be equipped with a riser control valve to permit isolating riser without interrupting the supply to other risers from the same source of supply". See Figures A.8.17.5.2.2.(a) and A.8.17.5.2.2(b) in the Appendix of NFPA 13, 2016 Edition for details of Acceptable Piping Arrangement for Combined Sprinkler/Standpipe Systems.

Jonathan Joseph

8/4/2020 02:43:02 pm

A control valve could also be your backflow or PIV.
All other control valves are Isolation for the vertical combo standpipe risers
A check valve is required if you are not attached from a backflow preventer.
A flow switch is generally attached downstream of the main drain from your standpipe distribution and does not have to be monitored but will act as the audible for the fire bell on address side.

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