We don't have quite the problems some areas have with water limits except in some areas. We did, however, recently do some work where even a real flow test had to be run thru their modeling, degraded, and then sent out for use. Alas, once they degraded a 58 PSI supply to a 28 PSI supply, I couldn't feed one or two heads in a student apt with it. Evidently in their model they program in some background noise: The big mall is burning, 12 alarm fire 30% of the population is washing their car 20% are filling their pool 1500 gpm is going to another fire within the block I'm not sure whether it represents reality, but it certainly is conservative. The result was a supply that has had no problem supplying sprinkler in the block in the past now can't put out .05/sf. When I asked about the 3-story dorm we'd done around the corner in 2001, and if this was a true representation of the water supply, shouldn't those folks be evacuated ASAP, there was a deafening silence. i.e., you're stuck with this but we're turning a blind eye to existing "problems"- whether they know its not a problem or not, they didn't reveal. Developer paid for 12 13d tanks and pumps, 8 #20 pumps for 13R's and we avoided dealing with 30 taps and UG lead-ins. Call it $200k. That's degrading. I'm sure modeling can be done accurately. So can hydraulic calcs, but from those I know GIGO applies. Garbage IN, Garbage OUT.
glc -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Ron Greenman Sent: Friday, September 04, 2009 11:57 AM To: [email protected] Subject: Re: NFPA 25 Proposed Routine Water Supply Testing And who's going to let you flow that kind of water. Out this way we're already and increasingly finding jurisdictions that want even the main drain test water reclaimed which, if extrapolated to municipal grid testing, is further trending towards modeling as THE means of predicting availability at all sites. On Fri, Sep 4, 2009 at 8:53 AM, George Church<[email protected]> wrote: > Incredibly, I was going to be much briefer and simply note that drain tests > -WHEN THE RESULTS ARE COMPARED WITH PAST PERFORMANCE-and the base line from > original installation is known. > > Maybe hydraulic placards should have a space for original drain test during > acceptance testing? > > And I think requiring a flow test off the floor flange (once water is > available) before/at/near start of installation would be a GREAT way to > ensure the water supply analysis is correct and translated from TEST to SITE > (FF) correctly. Hopefully before all the pipe is fabbed and delivered. > > Otherwise, despite our attempt to verify with drain test, we're simply > measuring the environment with the (maybe incorrect) assumption the supply > analysis was correct. And I don't even want to know how often it's flawed. > > glc > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Roland > Huggins > Sent: Friday, September 04, 2009 11:24 AM > To: [email protected] > Subject: Re: NFPA 25 Proposed Routine Water Supply Testing > > 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) > > _______________________________________________ > 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) > -- Ron Greenman Instructor Fire Protection Engineering Bates Technical College Tacoma, WA Member: SFPE, ASCET, NFPA, AFSA, NFSA AFAA _______________________________________________ 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)
