Wouldn't the throw at right angles to the nozzle be the harder thing to produce than throw inline to the orifice? If so then wouldn't the width be the more critical issue? Of course I'm now being Aristotelian using my fine logical interpretations and common sense to surmise a result from inadequate data. my son is in first year calculus and first year physics at the moment and it's great at sixty to have this kid reminding me that common sense rarely applies in science, particularly when you're working with a known three of eighty-five data points.
On Thu, Dec 10, 2009 at 11:05 AM, Todd - FPDC <[email protected]> wrote: > True. However, xcov sidewalls are listed with very specific flow and > pressure per coverage. As are residential sidewalls. All have fixed 16 > ft spray widths. In the exception I am citing, a pressure deduction is > allowed for a decrease in width alone. To me this seems inconsistant > and may actually produce an undesired result. It would make more sense > to figure the area based on the actual throw x 16ft. If the testing > proves me wrong, I'd like to see it. > > Sent from my iPhone > > On Dec 10, 2009, at 1:40 PM, Ron Greenman <[email protected]> wrote: > >> Todd, >> >> I think you're making the mistake of trying to apply thought to this >> process wherein you're not sure of what the testing criteria is. For >> my students I always draw out the test scenario for a residential head >> then ask them what happens if the third head operates. Good or bad? >> There always confused when I tell them the head fails the test >> particularly when I say not opening for the first two would also be a >> failure. They have problems with understanding that head fusing has to >> do with heat transfer rates in mass rather than ceiling temperature. >> They have trouble getting that concept that a model may or may not >> model the actual event but only be a device to predict acceptable >> results. And of course the all time biggie is that sprinklers aren't >> even designed to suppress, and that when they do it's a bonus, and of >> course the corollary that it's a success if the building (under 13D or >> 13R) burns to the ground as long as the occupants are outside watching >> it. At some point I have to accept that someone tasked with developing >> testing protocols has done so and that test somehow reflects >> performance vis-a-vis a set of rules and if I follow the rules, all >> other things being equal, I will obtain results equal to or better >> than the performance desired. The minute I start to logic this stuff >> out without knowledge of the criteria the performance requirement was >> subject to I'm start the long, slippery slope inducted Aristotelian >> explanations of phenomena. >> >> On Thu, Dec 10, 2009 at 9:38 AM, Todd - FPDC <[email protected]> wrote: >>> I get all that. But I assume most of the pressure in a sidewall is >>> for >>> throw and not width, how can we justify a significant decrease in >>> pressure based on a decrease in width alone? >>> >>> Sent from my iPhone >>> >>> On Dec 10, 2009, at 12:14 PM, <[email protected]> wrote: >>> >>>> What Roland has stated in both posts is correct.Most,if not >>>> all,residential sprinklers are listed for 13,13d,and 13r in >>>> residential applications.The minimum flow rates indicared in the >>>> data is that which is required to generate flow and pressure to >>>> achieve the spray pattern indicared.You still must discharge the >>>> minimum flow rate (.05 or .10) while at the same time the minimum > _______________________________________________ > 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, WSAFM _______________________________________________ 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)
