If you change pipe sizes, then yes you'd have to recalc. That's pretty much a given since your system hydraulics can change and you'll have no idea of the overall affect on the system performance.
Craig L. Prahl, CET Fire Protection Specialist Mechanical Department CH2MHILL Lockwood Greene 1500 International Drive Spartanburg, SC 29304-0491 Direct - 864.599.4102 Fax - 864.599.8439 [email protected] http://www.ch2m.com -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Charles Thurston Sent: Tuesday, May 11, 2010 4:32 PM To: sprinklerforum Subject: Pipe Size 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 Electronic Privacy Notice: This e-mail, and any attachments, contains information that is, or may be, covered by electronic communications privacy laws, and is also confidential and proprietary in nature. If you are not the intended recipient, please be advised that you are legally prohibited from retaining, using, copying, distributing, or otherwise disclosing this information in any manner. Instead, please reply to the sender that you have received this communication in error, and then immediately delete it. Thank you in advance for your cooperation ======= Email scanned by PC Tools - No viruses or spyware found. (Email Guard: 7.0.0.18, Virus/Spyware Database: 6.14970) http://www.pctools.com/ ======= _______________________________________________ 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) _______________________________________________ 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)
