The practice of connecting the relief valve discharge to the pump suction has been accepted for many years.It was removed from NFPA #20 in the nineties but has since been reinstated.I have done this many times for many reasons without any problems.Because it is a closed loop,I have not increased the discharge pipe size.
Hope this helps. ---- "A.P.Silva" <[email protected]> wrote: > > The building owner wants to connect the discharge piping from the pump > relief valve to the pump suction pipe, just upstream of the suction valve. > The water supply to the pump is a water storage tank. Anyone seen this > arrangement? Is it acceptable? > > NFPA 20, 2007 section 5.18.7 mentions "Discharge to Source of Supply". Is > this to the tank or can it be also to the suction pipe? Both 5.18.7 and > A5.18.7, seems to have a concern regarding the size of the relief valve and > discharge piping, but does not provide much guidance (in my opinion). Anyone > care to expand on this concern? > > The fire pump is rated 1000 gpm @ 105 psi. The source as mentioned > previously, are gravity tanks. The relief valve is 4" and discharge pipe is > 8" corresponding to Table 5.25. The discharge piping from the relief valve > to connection at pump suction pipe has one elbow. At the connection to the > pump suction there is a tee. Is the tee to be counted and the sizing be > increased as per 5.18.6.2 ? > > Any pump experts? > > Tony > > _______________________________________________ > Sprinklerforum mailing list > http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email to:[email protected] > (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
