NFPA13-10.10.2.1.3 Flushing Procedure

[Rober Cruz]

Gentlemen:

We have a 4" C900 underground pipe which must be flushing. We have carried out a procedure for said flushing using a 2-1/2" Sch40 steel pipe externally with a hose of the same size to divert the flow in places that do not affect the building. The fire pump has a flow rate of 500 gpm and is what will be used for cleaning.
Our question is, is there any impediment in using the 2-1/2" pipe for flushing the 4" pipe with the flow rate of the fire pump.

Best Regards
Rober Cruz

 

[LittleInch]

No.

But the pressure drop might be quite high which might reduce your flow rate.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[cvg]

33 fps probably not going to happen

 

[bimr]

You will only need about 150-200 gpm to flush the 4-Inch pipe. You will have to throttle the pump or send a portion of the flow to waste as the 2.5-Inch pipe will not flow at 500 gpm.