This highlights the importance of taking into account all of the variables that can affect a water supply as outlined in NFPA 13 and Ron's earlier discussion about safety factors. We have a situation where the local water purveyor conducted the water flow tests. They noted that they have a gravity-fed system with booster pumps to maintain tank elevations. But they didn't believe the booster pump operations would affect the water supply much at our site.
During fire pump acceptance testing we learned that the available supply was no longer as strong as we originally thought. After extensive searching for closed valves, retesting while city pumps were off as well as when they were running, we still are not certain why there is a weaker supply at the site than earlier in the year. But it appears that the city booster pumps must have been running during our original test, because they do improve the current supply somewhat. The point is, water supply testing and analysis is more critical than we normally recognize. How many times do you see folks taking a random flow test and designing to little or no safety cushion? Never mind the absolute idiocy of the ignorant PEs who allow competing contractors to conduct their own tests during the bidding process and then trust that the low bidder: 1) Tested correctly; 2) Accounted for normal fluctuations in the supply; 3)Isn't modifying the results to get a more favorable outcome for their bid price. I don't know all of the specifics of this case, but it seems to me the AHJ isn't responsible. If this was an "engineered" project that went to competitive bids, it's the engineer of record's responsibility to have considered the potential changes in the water supply. If this was a negotiated project, then the sprinkler contractor should have allowed for changes in the supply. Of course, it's possible that there were changes brought about by unforeseen circumstances - like George's bottle plants that took up significant water. Mark A. Sornsin, PE Fire Protection Engineer Ulteig Engineers, Inc. Fargo, ND Direct: 701. 280.8591 [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Greg McGahan Sent: Wednesday, September 23, 2009 3:20 PM To: [email protected] Subject: Inadequte Water Just fielded a question from an AHJ in a nearby community about being sued by an angry building owner that is saying the water pressure is inadequate for the sprinkler system. (Static pressure has fallen 5 psi since construction). If any of you have specific experience with a situation like this I would like to be able to help him with some stories. Greg McGahan Operations Manager Living Water Fire Protection 1160 McKenzie Road P.O. Box 877 Cantonment, Florida 32533 (850) 937.1850 | Fax (850) 937.1852 | Cell (850) 554.3231 [email protected] _______________________________________________ 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)
