The WHY part may be due to an inability to predict how many pumps will operate in any given scenario, so they flow all of them? You've done more legwork researching this than I have, but its one reason I can think of to flow ALL- it may because a BLEVE or massive rapid oxidation may cause enough pressure drop for all pumps to come on, and need to make sure that supply is sufficient to give em what they need? Might be that after a x minute minimum run some might shut off (due to their pressure being satisfied) but for the duration of the min run timer, they're running.
George L. Church, Jr., CET Rowe Sprinkler Systems, Inc. PO Box 407, Middleburg, PA 17842 877-324-ROWE 570-837-6335 fax [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Art Tiroly Sent: Tuesday, December 06, 2011 4:01 PM To: [email protected] Subject: RE: Simultaneous Pump Operation Your last question can be determined by hydraulic calculation. If you need 4000 gpm flowing then calculate the flow and pressure drop through 12" or larger pipe. Check velocity and psi drop. Arthur Tiroly ATCO Fire Protection Design Tiroly and Associates 24400 Highland Rd rm 25, CLE 44143 216-621-8899 216-570-7030 Cell WWW.ATCOfirepro.com -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Hinson, Ryan Sent: Tuesday, December 06, 2011 3:09 PM To: [email protected] Subject: Simultaneous Pump Operation NFPA 20 (2010) Section 14.2.5.2.3.1. "Where simultaneous operation of the multiple pumps is possible or required as part of a system design, the acceptance test shall include ALL PUMPS operating simultaneously." What is the rationale for "all pumps" versus required pumps to meet design? Is it purely for maintaining the suction header velocity below 15 ft/s as indicated in Supplement 4, Technical/Substantive Changes from the 2007 Edition to the 2010 Edition of NFPA 20? There is no reference indicating the cumulative flow required. Would system demand flow be used to meet this requirement since the pumps are already being flowed at higher necessary flows to conform to Section 14.2.5.2.4? Could it be to determine the capabilities of the electrical power supply to all pumps is in simultaneous operation? Additionally, I can find no indication of what sizing the test piping or number of connections need to be used for such a scenario. Thoughts? Ryan L. Hinson, EIT, SET Senior Fire Protection Engineer, Aviation & Facilities Group Burns & McDonnell Minneapolis-St. Paul Office 8201 Norman Center Drive, Suite 300 Bloomington, MN 55437 Direct: 952-656-3662 Fax: 952-229-2923 [email protected] www.burnsmcd.com<BLOCKED::www.burnsmcd.com> Proud recipient of PSMJ's Premier Award for Client Satisfaction -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://fireball.firesprinkler.org/mailman/private/sprinklerforum/attachment s/20111206/a2e100d7/attachment.html> _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum
