4" FDC Tieing into 3" Grid Main
4" FDC Tieing into 3" Grid Main
(OP)
Hey all .
I have a single riser for a mall building . I am coming off
my Grid main to feed my 4" FDC . My Drop is 4" diameter piping , My Grid Main is 3" .
do I need to up size my Grid Main to 3" ? I have checked NFPA 13 2008 8.17.2.3 ....
My Riser is 4" diameter , so I am thinking I would have to up size the 3" to 4" . But don't see anything in the Code to determine this .
any thoughts .
reference to NFPA 2008 8.17.2.3 , 8.17.2.4.1 , A 8.17.2.4.1
thanks
I have a single riser for a mall building . I am coming off
my Grid main to feed my 4" FDC . My Drop is 4" diameter piping , My Grid Main is 3" .
do I need to up size my Grid Main to 3" ? I have checked NFPA 13 2008 8.17.2.3 ....
My Riser is 4" diameter , so I am thinking I would have to up size the 3" to 4" . But don't see anything in the Code to determine this .
any thoughts .
reference to NFPA 2008 8.17.2.3 , 8.17.2.4.1 , A 8.17.2.4.1
thanks





RE: 4" FDC Tieing into 3" Grid Main
It sounds like you have a 4" riser and 4" bulk to your grid main. So, your FDC is mimicking the automatic supply.
Remember, the FDC is just an augment to the fire sprinkler system, and not a total replacement. If you have a typical mall, you are talking about 300 - 350 gpm (less if you have a QR reduction) for a total sprinkler demand.
Travis Mack
MFP Design, LLC