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 >> flow from the table.If you happen to over-flow the head thats >> o.k.,but you can't flow less than the stated minimum. >> >> Lamar V. >> >> >> ---- Roland Huggins <[email protected]> wrote: >>> agreed but BOTH the listing flow and the 0.1 by the SXL rule must be >>> evaluated as you indicated in your first message. Look again at the >>> process assigned larger rectangle (16 x 20) for listing and smaller >>> (18.5 x 12) for the SXL. Along with my prior message, the two should >>> resolve the question in your mind. >>> >>> Roland >>> >>> On Dec 9, 2009, at 4:05 PM, Todd - FPDC wrote: >>> >>>> This is a 13 system so a 0.10 is reqd. >>>> >>>> Sent from my iPhone >>>> >>>> On Dec 9, 2009, at 5:26 PM, Roland Huggins >>>> <[email protected]> wrote: >>>> >>>>> first off you are confusing the issue by stating 0.05 gpm/sf since >>>>> these are not density/area sprinklers. The 0.05 gpm/sf is a >>>>> minimum >>>>> flow but it is often exceeded by the listed require pressure for a >>>>> evenly assigned rectangle. AS in your case, the area for the 16 >>>>> x 20 >>>>> is 320 requiring only 16 gpm for the non-criterion 0.05 density. >>>>> You >>>>> identified the listing requires 22 gpm at 27.4 psi. So where's the >>>>> beef? >>>>> >>>>> Roland >>>>> >>>>> On Dec 8, 2009, at 7:38 AM, Todd Williams wrote: >>>>> >>>>>> I am reviewing a set of plans where the designer used residential >>>>>> sidewall sprinklers in 13 system (6 story apartment bldg). A >>>>>> particular room is 18'6 x 12' and he has a sidewall throwing the >>>>>> 18'6 >>>>>> and centered on the 12 ft wall. Since we have to use a 0.10 >>>>>> density, >>>>>> he based his design on 11.2.3.5.2. The listing for the sprinkler >>>>>> at >>>>>> the 0.05 density (16 x 20 sp) is 22 gpm at 27.4 psi. If we use the >>>>>> 0.10 density times the area as described per 8.5.2.1 (comment >>>>>> (2) in >>>>>> 11.2.3.5.2), we get 22.2 gpm at 27.9 psi. How can we expect to get >>>>>> twice the density at a an 18.5 ft distance out of the same flow >>>>>> and >>>>>> pressure by decreasing the width of a room? >>>>>> >>>>>> Todd G. Williams, PE >>>>>> Fire Protection Design/Consulting >>>>>> Stonington, Connecticut >>>>>> www.fpdc.com >>>>>> 860.535.2 >>>>>> _______________________________________________ >>>>>> 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:Sprinklerforum- >>>>>> [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:Sprinklerforum- >>>>> [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:Sprinklerforum- >>>> [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:Sprinklerforum- >>> [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:Sprinklerforum- >> [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, 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)
