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FDC and Hydrant Connection Proximity - Impact to Flows

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khu

Civil/Environmental
Aug 8, 2019
25
Are there any restrictions with having an FDC connection located within ~ 10' of a hydrant connection on the same 12" line? I imagine there would be an impact to fire flow if the suppression system was running and they wanted to hook up to the hydrant, but I don't really do much modeling. The site is fairly constrained on where these can be located and the only real feasible layout is for FDC and hydrant to share a landscape island.
 
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No, BUT if I'm reading your question and description of where you are wanting to place and connect the FDC correctly, it will not work.

The FDC must tie into the sprinkler system downstream of the control/backflow valve. FDCs are typically located on the exterior wall for economic reasons. Beyond that there are no restrictions that I am aware of on where to locate the FDC.
 
Basically, there are 2 6" tees at the 12" main. One feeds the fire suppression system, first entering the DCDA vault then heading to the building. The FDC ties in on the downstream line of the DCDA. The second 6" tee, roughly 10' away from the first, at the main feeds the hydrant assembly.
 
Call the owner of the water system and the Fire Dept. They will tell you what can be done.
 
There are rules associated with the clear space around both fixtures, so be mindful of those.
The FDC and Post indicator Valve PIV (which is sometimes connected to the backflow or just downstream of the backflow) allows the Fire Department to take control of the sprinklers.
One action is to connect engine to both and close the PIV, this allows them to increase the flow or shut it off when the fire is out or Fire Fighters are in the building.

Hydrae
 
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