size does matter, as a later poster noted; but the requirements we're trying to satisfy are different. We calc the flow and pressure for the MOST DEMANDING AREA. But the longest transit time is what we're proving with the ITC location.
Say you have an area with 60' wide BB Attic heads, then the building skinnies down to a 12' wide rear addition that goes back 50', say 100', possibly taller than the MRA, but subdivided into 12' x 12' rooms, protected by a row of 1/2" SSU. So the MRA for hydraulic calcs would be 15 GPM at 7 PSI at the end head. Not the most hydraulically demanding, but certainly longest travel time-since the ATTIC BB's are on the way to the rear addition. If you have a cut-up building with multiple candidates for an ITC, you could use the water delivery software to model the various options and see which IS most demanding. I can't recall the last time an ITC location was questioned, but that would enable you to provide DATA to support your view (or installation, depending on WHEN the issue is raised). Don't put me down for pushing for this, I think a mountain might be forming under a mole- seriously, how often has this issue cropped up in over a decade of Forum posts? How many buildings are burning down due to improperly tested dry systems cause the ITC wasn't in the absolute furthest point- let's face it, an exterior wall is a nice place for an ITC. More likely we lose buildings protected by dry systems cause the accelerator is OFF or otherwise not working. If there is a hidden beauty to investing in an electronic accelerator, its that it's likely to work more than once, and still be on when your guys get back to the shop. There are larger variables to deal with in dry system trip testing, like is it when water spits out or a sustained flow or a specified flow and pressure equal to the end head pressure for a head in the MRA? And i know of folks who sure take a L O N G time to open the ITC valve- and click the stopwatch when its fully open. glc -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Matthew J. Willis Sent: Monday, July 19, 2010 2:07 PM To: [email protected] Subject: RE: dry inspectors test "distance" Todd, I believe it is linear feet. The "most distant" point for water to travel (the most time), nothing to do with demand. Size would not matter. R/ Matt Matthew J. Willis, CET Automatic Fire Sprinklers Norred Fire Systems L.L.C. 318-387-1134 Voice 318-816-1087 Mobile 318-387-1163 Facsimile [email protected] > >-----Original Message----- > >From: [email protected] > >[mailto:sprinklerforum- [email protected]] On Behalf Of Todd > >Williams > >Sent: Monday, July 19, 2010 12:59 PM > >To: [email protected] > >Subject: dry inspectors test "distance" > > > >NFPA 13 (2007) section 8.17.4.3.2: "The trip test connection shall be > >located on the end of the most distant sprinkler pipe..." How is > >"distant" calculated? I assume this means it is independent of > >hydraulic remote areas? Does pipe diameter play into this at all? I > >am working on an attic system with Tyco Attic BB and AP sprinklers > >and the physically distant is very different than the hydraulically > >remote area. > > > > > > > >Todd G. Williams, PE > >Fire Protection Design/Consulting > >Stonington, CT > >860.535.2080 > >www.fpdc.com > > > >_______________________________________________ > >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) No virus found in > >this incoming message. > >Checked by AVG - www.avg.com > >Version: 9.0.839 / Virus Database: 271.1.1/3009 - Release Date: > >07/19/10 01:36:00 _______________________________________________ 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)
