Sounds like a good opportunity for a public input. Sent from my Motorola Smartphone on the Now Network from Sprint!
-----Original message----- From: Dwight Havens <[email protected]> To: "[email protected]" <[email protected]> Sent: Fri, Jul 26, 2013 17:57:21 EDT Subject: Re: SIGN for Backflow Prevention Assembly Forward Flow Test Then they ought to say that in the code language. Dwight ________________________________ From: John Denhardt <[email protected]> To: "[email protected]" <[email protected]> Sent: Thursday, July 25, 2013 3:07 PM Subject: RE: SIGN for Backflow Prevention Assembly Forward Flow Test While I do disagree to some extent of what the NFPA 25 committee has done, Roland statement is correct. I have had numerous discussions with NFPA 25 committee members where they have stated the intent was to exercise the device at near system demand. The key word to me was "Exercise". John John August Denhardt, P.E., FSFPE Strickland Fire Protection Incorporated 5113 Berwyn Road College Park, Maryland 20740 Office Telephone Number: 301-474-1136 Mobile Telephone Number: 301-343-1457 FIRE SPRINKLERS SAVE LIVES - Can you live without them? -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Forest Wilson Sent: Thursday, July 25, 2013 2:42 PM To: [email protected] Subject: Re: SIGN for Backflow Prevention Assembly Forward Flow Test Here is an email on this topic that Roland addressed in the past: Im not going to say it was one of those casual assumptions that all systems are calculated nor that all risers have placards. The main thing to keep in mind that the intent is simply to fully EXERCISE the BFP at what os expected to be the system demand. If no data available, a discussion with the AHJ is warranted. As for benchmarks, only the flow is pertinent and pressure is irrelevant. Roland On Dec 22, 2009, at 2:44 PM, Matthew J. Willis wrote: >> >> On a more important matter: If a system was retrofitted with a >> backflow, > and >> there is no hydraulic calc plaque attached to the riser, and NFPA >> requires >> forward flow testing of backflows, how can you conduct the test >> without a >> benchmark to test against? >> >> What is the recommended practice in this scenario? >> Forest Wilson Sent from my iPhone On Jul 25, 2013, at 12:16 PM, Ron Greenman <[email protected]> wrote: > Then subjective good flow demonstrates a working valve? If so all the > numbers bantered around are pretty meaningless. > > > > On Thu, Jul 25, 2013 at 8:07 AM, Forest Wilson <[email protected]>wrote: > >> No. >> The intent is not to pitot the output but to exercise the valve. >> >> >> Sent from my iPhone >> >> On Jul 25, 2013, at 10:56 AM, Ron Greenman <[email protected]> wrote: >> >>> Forest. What were you flowing to discover these failures? Main drain or >>> some special test header? Would a sign with the data requested by the >>> customer that started this thread have had any utility in helping you >>> discover the problem? >>> >>> Then back to that perennial question of what's a "full flow " test and >> how >>> do you do one? I think Roland said the intent was to flow an equivalent >> to >>> the design discharge criteria. How do you do this? Do we run a pitot >>> somewhere on the system? Do we catch and measure discharge? If so, from >>> where? How do we arrange the test port(s)? Do we flow the design area or >>> simulate it elsewhere? Do we need results of at least or better flow or >>> right on the money flow? If not either of those how do we judge? >>> >>> Doesn't the hydraulic data plate note the required psi per the calcs at >> the >>> BOR and the static? Isn't the difference the residual drop at that point >>> relative to the design area? Wouldn't a main drain with good flow at a >> psi >>> around the BOR rating, and returning to close to the noted static when >>> terminated suggest a fully open valve, or an adequately open valve if the >>> UG is oversized? In the latter case the partially open valve is >> equivalent >>> to fully open for the system I just described. Am I missing something >> here? >>> An erroneous a priori? My understanding of hydraulics wrong? Main drains >>> are too small to simulate the result of all design area heads flowing as >>> the water passes through the BOR? >>> >>> >>> On Thu, Jul 25, 2013 at 7:34 AM, Forest Wilson <[email protected] >>> wrote: >>> >>>> I still have the check valve from a Ames that failed to open. >>>> It was jammed shut, discovered when I was called out because they >> couldn't >>>> do the fire pump test. >>>> >>>> In another case, I tested a backflow and it failed (on a Best Buy >> store). >>>> I opened the valve up and the check was _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
