Check Valve Needed in Multi-Riser Manifold?

1/8/2019

For a horizontal manifold that contains multiple sprinkler systems, are check valves needed for each sprinkler system? In this case there are no standpipe systems in the building.

As I understand it, NFPA 13 only requires a check valve on the incoming fire department feed, but each of the different system risers have no requirement for a check valve.

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9 Comments

Pete

1/8/2019 10:20:53 am

They are not required. The benefits of using an alarm check or a riser check valve are: 1) 8.16.1.1.3.5 (paraphrasing) for a single riser system, these system valves can serve as the FDC check valve. 2) For system maintenance, to keep the other systems on the header in service (control valves open) while draining back a single system on the same header, you will need check valves.

PETE

1/8/2019 10:24:33 am

The simplest wet riser consists of an indicating control valve, a drain, a flow switch, and a pressure gauge. https://www.reliablesprinkler.com/sites/default/files/products/bulletins/621.pdf

Julian

1/15/2019 08:43:39 pm

What about a standpipe for a five-story?

Brian Gerdwagen FPE

1/8/2019 03:49:20 pm

The biggest reason not yet stated is that a check valve isolates the flow switch. Also: a check valve is required on each system riser per NFPA 13 2019 16.11.3.1

JAMES

1/9/2019 06:15:09 am

This section was brought from the previous NFPA 13-2016 6.8.2.1; it permits a listed alarm check valve, or, other listed waterflow detection alarm device. You can use an alarm check valve and it should isolate the flow switch and help prevent unwanted paddle movement, but I'm not sure that it's required.

Nimal Tissa Wijetunga

1/8/2019 09:42:40 pm

Yes. Check valve is required in each riser connected to different sprinkler systems in relation with floor area limitation of each system according to the Occupancy category for .Sprinkler design.

JAMES

1/9/2019 06:18:10 am

Nimal, where in code are you seeing this?

Each isolated system has to be within it's area limitations, but I don't see where that's mandating a check valve in each.

Brian Gerdwagen FPE

1/9/2019 02:27:58 pm

The check valve is in the definition of a system riser. There is an exception for a single system riser utilizing the backflow as the only required check.

JAMES

1/9/2019 02:37:33 pm

Here's what I'm pulling from the 2016 edition of NFPA 13. I'm interested in your take - because if it needs to be there it needs to be there - I just haven't come across check valves in all wet systems before.

The definition of system riser -

3.5.13 System Riser. The aboveground horizontal or vertical
pipe between the water supply and the mains (cross or feed)
that contains a control valve (either directly or within its supply
pipe), a pressure gauge, a main drain, and a waterflow
alarm device.

I'm used to seeing a single backflow preventer serve a multi-riser manifold, but without a check valve on each wet system.

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