Allow me a bit of a long winded response instead of a simple yes or no. First off, although your question is not about whether you can omit sprinklers but whether you have to have a 3,000 sf remote area (not stated but understood since you are referencing chap 11), let’s start in 8.15.1.2.6 that allow the omission. It states - the joist channels are firestopped into volumes EACH not exceeding 160 cu ft. Obviously the volume is per individual channel. Now jumping to 11.2.3.1.4(4)(j) it states - provide the adjacent joist space channels are firestopped into volumes not exceeding 160 cubic feet. I could stop here but the coffee is kicking in. IF it were meant to be a single channel, the text would have been copied as stated in 8.15.1.2.6. Stating “adjacent channels” when read without the preconception from 8.15 is pretty plain but it was known that the per channel was well ingrained so Annex material was provided. It states - restrict the ability for fire to spread beyond 160 cu ft zones covering MULTIPLE joist channels.
Prior to the 2010 edition, you ALWAYS had to use a 3,000 sf remote area with unprotected spaces of composite wood joists. By breaking the overall space into volumes of NMT 160 cu ft, it presents a similar risk that that of solid wood joists with bigger individual channels. For our sprinkler scientist, yes it is a slightly bigger risk since TJI's burn more vigorously and fail more quickly than solid wood joist (thus the prior difference) but for driving the need for a bigger remote area, the difference is insignificant. Roland Roland Huggins, PE - VP Engineering American Fire Sprinkler Assn. --- Fire Sprinklers Saves Lives Dallas, TX http://www.firesprinkler.org <http://www.firesprinkler.org/> > On Oct 21, 2015, at 5:08 PM, James Crawford <jcrawf...@phaserfire.ca> wrote: > > We have a project that is using TJI wood joist (composite wood Joists), they > are 16” deep spaces 18” on center and are 20’ long. There is gypsum board > attached directly to the bottom of the joists along with 3” of insulation at > the bottom to reduce sound transmission. The area is about 1400 sq.ft. > > > > Reference is NFPA #13 2013 edition section 11.2.3.1.4(4)(j) > > > > Light or ordinary hazard occupancies where noncombustible or limited > combustible ceilings are attached to the bottom of composite wood joists > either directly or on to metal channels not exceeding 1” in depth, provided > the adjacent joist space channels are firestopped into volumes not exceeding > 160 cubic feet using materials equivalent to ˝” gypsum board and at least 3 > ˝” of batt insulation is installed at the bottom of the joist channels when > the ceiling is attached utilizing metal channels. > > > > If each channel space formed by two joist is 40 cubic feet, so the adjacent > space is 40 cubic feet, I see no need to fire stop them into volumes less > than 160 cubic feet as they are already less than 160. The AHJ is saying > that we must firestop every 4th joist space with gypsum to create spaces of > 160 cubic feet, so we would need to break the space into 12 spaces of 160 > cubic feet for the 1400 sq ft area. > > > > Am I reading this correctly or do we need to break the space into sections > of 160 cubic feet? > > > > Thank you > > > > > > James Crawford > > Phaser Fire Protection Ltd. > > Phone 604-888-0318 > > Fax 604-888-4732 > > Cel 604-790-0938 > > Email jcrawf...@phaserfire.ca > > > > _______________________________________________ > Sprinklerforum mailing list > Sprinklerforum@lists.firesprinkler.org > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list Sprinklerforum@lists.firesprinkler.org http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
