One too many 'the's at the end of your disclaimer Cecil. Not complaining or intending to criticize, I'm just a stickler about some things. b'rad
> On May 20, 2014, at 9:26 PM, Sprinkler Academy - C Bilbo > <[email protected]> wrote: > > Hiya Chris, (we'll meet face to face some day, right?) > NFPA 13 is a "prescriptive standard" (for those wondering: a standard that > will cover just about any situation within certain parameters, so anyone can > apply it). Which means we follow the rules as written. > You are doing it right when you use the full 46.5' as the basis along a > branchline that crosses rooms. > Our trade is based, founded, and entrenched in the ability to apply these > rules in this way. The rules are DEFINITELY too conservative for many > situations. But that is what makes our prescriptive methods so successful. > If it is enough for tough situations and too much for others, then we are > sure to have the good record that we have created. > To espouse a view, as has been suggested, that says to the vast majority of > contractors and designers, "Do what feels good." is NOT an appropriate > answer. > The purpose of the remote area being 20% longer than the square (the square > root for an inscribed circular fire...) is to make it more demanding on a > single branchline and therefore a more conservative prescriptive system. > (See the Academy's free remote area 101 lesson.) > Chris, I know you to be a fair and firm professional. There is reason here > to maintain and require consistency. (Give em an inch and.....) > Stick with the definitions in the IBC/Minn and the NFPA and reality will be > grand. > It should be recognized that the above is my opinion as a member of the NFPA, > and has not been processed as a formal interpretation in accordance with the > NFPA Regulations Governing Committee Projects and should therefore not be > considered, nor relied upon, as the official position of the the NFPA, nor > any of their technical committees. > > Sincerely, > > > Cecil Bilbo > Academy of Fire Sprinkler Technology > Champaign, IL > 217.607.0325 > www.sprinkleracademy.com > > [email protected] > > > > OUR STUDENTS SAVE LIVES!! > > > >> From: [email protected] >> To: [email protected] >> Date: Tue, 20 May 2014 19:12:41 -0500 >> Subject: Area/Density Method and Walls >> >> I can't believe I'm asking this question after all these years. Anyway, >> swallowing pride and asking. >> >> 2010 NFPA 13 strict Density/Area method 11.2.3.2 and 22.4.4.1.1. Great big >> room being subdivided. Existing system with a new wall added between heads >> on a BL. Contractor had to add a head on one side to preserve the existing >> spacing (area) of the heads. Without head over 130 sq.ft. I take the 1.2 >> ^.5 of the area and get 46.5' required along the BL. Original system lets >> say calc'd 5 heads on the BL. But now in the same 46.5' there are 6 heads >> on the BL. Do I ignore the wall and require a new calc? What if the wall >> is rated 1 hour do I ignore it? >> >> I looked all over and can't seem to find anything definitive. Room design is >> out so not a consideration. 22.4.4.1.1.1 simply says all the heads in the >> 46.5'. I can't find anything that says either to count the wall as a break >> so measure 46.5' from the wall in each direction and still see if there are >> 5 head or ignore it and there are now 6 heads. I find 11.1.2 that clarifies >> to extend the density or not. I don't think that's applicable exactly. The >> question is not about whether to extend the density on either side. Let's >> just say it's all OH. >> >> It gets a little more complex as on the one side of the wall they cut a head >> in on the BL but on the other side there is a perpendicular new wall and >> they come off same BL and arm over to two more head so if I ignore the walls >> there are now 8 heads off the 1 BL. >> >> Prefer a code section or written reference 'cuz this is going to be a big >> deal if we ignore the walls. Ordinarily with unrated walls they are ignored >> in density/area (of course can't find that reference). I think I'm getting >> tripped up with the rated portion? Or maybe I'm just tired???? >> >> Chris Cahill, PE* >> Associate Fire Protection Engineer >> Burns & McDonnell >> Phone: 952.656.3652 >> Fax: 952.229.2923 >> [email protected]<mailto:[email protected]> >> www.burnsmcd.com<http://www.burnsmcd.com/> >> *Registered in: MN >> >> >> Proud to be #14 on FORTUNE's 2014 List of 100 Best Companies to Work For >> >> >> >> >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
