If it is a relatively new pump, it may churn at 140% but I'd be shocked if that were the case. I haven't gone looking but has any one seen a horizontal pump that exceeds the old 120% criteria? The pumps I've played with have been less than 110% and there are a boat load that are at or below 105%. As such, it seems the answer to you discharge problem may be to evaluate the actual system and do away with the relief valve. Keep in mind that the outlet pressure is not limited to 175 psi but to the pressure rating of the components so location (that is impact of elevation differences) is applicable.
Roland On Mar 20, 2009, at 10:38 AM, A.P.Silva wrote: > True. Good point. > > I should've mentioned the pump is diesel. The tank is 40' high. To > conform > to NFPA 20, 2007 section 5.18.1.1, 121% of churn gives (105 x 120% x > 121%) + > (40 x .433) = 170 psi (approx), assuming churn pressure is 120% of > rated > pressure. Someone would have thought it was not too far from 175 > psi. I > wasn't involved with the original design. > > > > 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)
