400 Sprinklers is the max on an 8" pipe schedule riser, 275 on a 6" riser. Before your time I guess. 400 is still max at 52000sf and 40000sf warehouse systems at 100sf/hd.
Arthur Tiroly ATCO Fire Protection Design Tiroly and Associates 3300 King Ave Cleveland, OH 44114 216-621-8899 216-570-7030 cell -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Todd Williams Sent: Wednesday, June 17, 2009 7:46 PM To: [email protected] Subject: RE: Slow responding dry pipe valves-FDT George, I believe that the 52000 sqft came from 400 sprinklers x 130 sqft per sprinkler. The 400 someone probably pulled out of a body orifice. If you want to pick nits, sprinklers discharge water in a circle and we calculate them in a square. How come we don't have circular remote areas? Do uncontrolled fires burn in a more circular or rectangular pattern? Also, in pipe schedule systems, there was no modification in pipe size between wet and dry, but there is in hydraulically designed systems. Why? At 07:31 PM 6/17/2009, you wrote: >Well, the 60 second rule pre-dates the software by a LONG time, so I there's >no TFP#13 where a code change triggered or mandated sales. And nothing in >#13 requires the use of the software. We look at it as working smarter and >managing the risk of having to add a DPV during acceptance tests or being >able to reduce # of dry valves as much as being able to escape some last day >acid test you pass of fail. > >I'm not aware of any significant failures of dry systems beyond the usual # >of fires that come to my attention from casually coming across them, I don't >scan the web for fire news in my free time because I really don't have much >of it. > >I think of FDT more like back when you had the option of pipe schedule vrs >calc'd- say late 70's to early 80's- when if you saw a new system with 8" >riser you knew the water pressure was bad or they's have calc'd it. If they >didn't have calc software, they saved money on software/pc/operators and >installed 8" risers (hmm, I see a parallel). > >Data? This industry doesn't need no stinkin data. Only in the last couple >years (AT CONVENTION, AT 2AM) did I learn the basis of the area-density >tables in 13 were simply "let's run a test, plot the results that worked, >and then draw a line either side at +37% and -37% (exact values escape me >now) and that got carved in stone and we've all trusted it for years as if >it were based on a significant amount of testing or modeling. And the fact >that the systems have performed pretty darn well for decades means they got >it right- even if it was by accident or good guessing. > >Seriously, we do have Data. We seem to either rigorously apply something so >old we don't know where it came from (52,000 SF per system) or we have calc >programs taking accuracy to .0001 but nobody took the 15 PSI tank gradient >drop into consideration. Fires don't start in 1.2xMRA rectangles, >commodities change over time, ITM gets missed, cut, or results aren't >compared with the past, and some of the badge-heavy think this is a perfect >science when all we can possibly do is provide a reasonable level of >protection and hope it works when and if needed. > >Many of us need to take a step back and look at the big picture. Pipe >scheduled systems saved a lot of buildings back when we didn't know what we >know now, and anyone who's tried a reinforcement no longer even tries to >keep the 1' when piecing together a grid from adjacent trees, and if it >isn't LH, toss the 1.25" also. But the application of perfect to an >imperfect and fluid world is silly. > >Had a spec on a job we bid today require we pitch the piping downstream of >the main drain valve at 1/16" per foot, I forget what the rest of the system >was to do but there were criteria. What were we to measure from? If we're >trapped below grade in a basement, did it really matter, it goes in a >bucket. Funniest part of this LONG spec was how good it must have sounded in >the polished ivory tower when written; but the application is hilarious- >THEY ARE DEMO'ING AN OLD BOWLING ALLEY IN AN OLD BUTLER BUILDING AND >INSERTING A SURGERY CENTER IN THE SHELL!!! So how could 1/16" pitch be >something in the relevant range of accuracy when the floor slope, steel sag, >etc are all 100x off compared to 1/16" for anything in our world? > >-----Original Message----- >From: [email protected] >[mailto:[email protected]] On Behalf Of Ron Greenman >Sent: Wednesday, June 17, 2009 6:44 PM >To: [email protected] >Subject: Re: Slow responding dry pipe valves-FDT > >So what drove the change from the old way of working trip times (under >500 gal. all was good, 500-750 gals. and either 60 seconds or QOD, >over 750 gals. QOD and all is good)? was it due to systems failing due >to too long trip times or was it a way to sell an expensive computer >program? If due to failures did it happen in a cross section of >buildings or in certain types of buildings and if the latter is it >necessary to treat all systems equally? Certainly requirements to trip >test everything to 60 seconds in years past was based on local >requirements arrived at collectively by AHJs because they wanted it >and it was complied with enough to become the usual thing to do until >it became codified--first locally and then in 13. Where's the data >that supported this costly change at point in this migration from what >13 said to what it says now? Enquiring minds want to know. > >On Wed, Jun 17, 2009 at 1:08 PM, George Church<[email protected]> wrote: > > To address Mike's concern about trip time, the QRS switch is pretty > > dependable- it samples the air pressure every .1 seconds and after enough > > degradation is detected 3x in a row, it trips. We input 3.5 second trip >time > > > >_______________________________________________ >Sprinklerforum mailing list >http://lists.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) Todd G. Williams, PE Fire Protection Design/Consulting Stonington, Connecticut www.fpdc.com 860.535.2080 _______________________________________________ Sprinklerforum mailing list http://lists.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 http://lists.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)
