Since everything is remaining the same except the diameter of the last piece of pipe, the question you have to answer for your AHJ is - does the change increase or decrease the system demand when compared to the original calculation? That will answer your question.
Roland On May 11, 2010, at 1:31 PM, Charles Thurston wrote: > Hello All you Fine folks of the Sprinklerforum, > > I am looking at replacing all the pipe in a 2 story parking deck > due to external corrosion (The fitters will love to be to look at > the beach while they "work"). 3" main fed from a 500 GMP ??PSI pump. > The building the pump feeds is 16 stories of condos. > Each branch line feeds 5 heads now. > 1 1/4" from main feeds heads 1-4 and 1" to the 5th head. It will be > cheaper to run the branch line all the way out in 1 1/4 fitting and > machine adjustment wise. The AHJ "ask" if it was allowable to change > the pipe size without re-calcing the entire system. It is planned to > measure out the pipe lengths and out the heads back in the same > locations. I have not found anything in NFPA 13 2007 addressing > this. Does anybody know a reason not to run 1 1/4" all the way out > other than to "balance the flow" in the last head. > > -- > Best regards, > Charles Thurston mailto:[email protected] > Coastal Fire Protection/ Myrtle Beach Fire & Safety Group. > AFAA Guest > _______________________________________________ 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)
