A wrinkle in that approach is that the BFP flow is simply to exercise the device at (or near) total system demand WITHOUT measuring pressure loss.
Although testing the water SUPPLY for deterioration is a noble idea, it is so far beyond reasonable that we are attempting to pick the fly sh.. out of the pepper. Following a Federal attitude that cost is irrelevant and testing ANYTHING that could impact the system is not the intent of NFPA 25. OK lets side step the issue of just how expensive do we want these tests to be (noting that too many dollars required pushes owners toward enjoying the services of curb testing trunk slammers resulting in NO assurance of performance). Lets also side step the FACT that NFPA 25 inspections by others only verifies MECHANICAL condition and NOT whether the system is adequate for the contents. Lets consider some technical aspects. Keep in mind we are testing the municipal supply. IF the purveyor throttles back on the pumps, would this not show up as a reduction in static pressure on the main drain test? If the system demand has greatly increased such that there is an additional 10,000 gpm flowing in the main, would that not show up as a reduction in static in the main drain test? The rebuttal to these questions at the table was to identify the weakness in the main drain FLOWING test to identify reductions in the ability of the the private main's flow ability. THAT is a different issue that challenges the main drain test but not it's ability to detect significant changes to the municipal water supply. IF the reduced capacity is too small to detect without a major stress on the water supply, where is the case history showing that as a failure mode for sprinkler systems? ANY GUESSES ON HOW I VOTED? Where's the shaven headed woman screaming Stop the Madness when you need her? Roland On Sep 3, 2009, at 9:48 PM, Michael Fitz wrote: > This should not really be a problem in that every Backflow Prevention > Assembly and Backflow device is already required to be flowed > ANNUALLY at > the system demand including hose streams (12.6.2.1 and 16.6.2.2 in > the 2002 > version). People should already be figuring out how to do that > including > measuring the flow, with the exceptions allowed. > > How about suggesting a revision to that proposal to allow water supply > testing through the system at least to the system demand such that the > pressure can be compared back to the base of the riser (or whatever > calculation point is used)? This will provide yearly confirmation > that the > system is providing the required flow at the required pressure. > > Sure sounds like something that every insurance company would like > to see > recorded, including the contractors, what a better way to reduce your > potential liability. > > Just put a hose monster on the system and develop several points to > get a > develop the supply curve. The curve would end at system demand (or > slightly > above) and hopefully the tested pressure is (well) above the required > pressure. > > Michael M. Fitz, P.E., C.F.I. > MDE Inc. _______________________________________________ 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)
