Lamar, I agree with you that the codes allow an approved PRV on the system side (= downstream) the fire pump discharge valves. The system side of the fire pump discharge valves is where NFPA 20 ends and NFPA 13 (or 14) takes over. So NFPA 20 - 2007 par. 5.7.6.2 ( = 2010 par. 4.7.7.2) does not apply. And NFPA 13 allows PRV's. Design everything upstream the PRV for 250 or 300 psi and everything downstream for 175 psi.
My fellow technical advisors in this country would ripost that there is no good reason to reject a Pressure Relief Valve on one side and accept a Pressure Regulating Valve on the other side. Both can fail. A relief valve can fail in open position as easy as a regulating valve can fail in closed position. In both cases there is too little or no water downstream. So, if the codes accept a pressure regulating/reducing valve, then a pressure relief valve should be equaly acceptable. A pressure relief valve that fails with the valve in open position means -> too little water to the sprinklers. A pressure reducing/regulating valve that fails in closed position means -> no water to the sprinklers. Do we really want a pressure reducing/regulating valve? Frans Stoop TOS architecture & fire protection Netherlands <[email protected]> Tel. +31-24-324 0112 At 13:51 6-4-2010 -0400, you wrote: >Another way to deal with this issue is to use an approved pressure >"REGULATING" valve in the pump discharge line.Granted this will take >a lot more space and probably is more expensive,but,is an accepted >method to achieve the shut-off pressure needed for the system. > >Lamar Vaughn , SET _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.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)
