NFPA 14 - Class I Standpipe - Drain Riser and Main Drain

[daaguirre]

I am designing the drainage systems for a large apartment complex which will have a manual wet standpipe system and a large classroom building which will have a combined manual wet standpipe system / automatic fire sprinkler system. The fire suppression systems wont be designed by my firm (They will be designed and installed by the general contractor). However, I would like to include in my design any drain receptors that may be required for the standpipe system.

Per NFPA 14 - 7.11.1 A permanently installed drain riser is required on each standpipe equipped with pressure-regulating devices to facilitate testing. Is there an easy way to tell if pressure regulating devices (and the drain riser) will be required? - FYI The buildings are not considered high-rise -. Also, how does the drain riser connects to the building drain? Would a floor drain near the standpipe be an acceptable solution? If someone could share a detail of how this is done, that would be great!.

Per NFPA 14 - 7.11.2 a main drain is required on the standpipe system side of the system control valve ( I assume this would be close to the backflow preventer), and additional drains are required for portions of the standpipe that are trapped such that they can not be drained through the main drain (I would assume all the hose connections on the lowest level of each stair). Again, how is this typically done? Would a floor drain near the hose connections suffice?

Attached is a picture that I took of a combined automatic sprinklers / standpipe system. Unfortunately, the drain riser connection to the drain receptor is not visible.

 

[TravisMack]

You have a manual standpipe system. That means the pressure is supplied by the fire dept connection. There will very likely not be pressure reducing valves on the standpipe that will require a drain riser.

There will quite possibly be one stair (or more depending on size of project) that will be a combination standpipe that will also supply the sprinklers at each floor. There will be a control valve, check valve, flow switch and test/drain at this location (unless you are dealing with Marriott properties which require a remote insp test connection). The floor drain will likely be connected to a common drain riser (likely 2" diameter pipe). Typically, these drains will terminate to the exterior (California has requirements that it goes to a floor drain).

The main drain on the standpipe control system will likely be near the backflow preventer. This will likely be a 2" drain. In most cases it will just discharge to the exterior. However, certain jurisdictions may have requirements that specify where the drain will discharge.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

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