Keep in mind that the firestopping is equivalent to the web material so you only have to do anything if the joist channel exceeds 160 ft3. Correct on the 3,000 sf which applies to ceiling attached to composite wood joists (solid wood joists do not require it). There is an allowance that was added to the 2010 ed whereby composite woods joists do nt require a 3,000 sf remote area when firestopped into areas of no more than 160 ft3 using a more resistive material such as 1/2"gypsum. THIS DOES NOT MEAN EACH JOIST CHANNEL . It is purely based on volume and can be 4 channels if each channel had a volume of 40 ft3.
Roland On Jan 28, 2013, at 2:37 PM, Bobby Gillett <[email protected]> wrote: > Anyone want to verify or argue my thought process on this? (please) > > Bobby Gillett > Sr. Project Manager > Key Fire Protection, Inc. > (731) 424-0130 office (731) 424-9285 fax > (731) 267-4853 cell > www.keyfireprotection.com > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Bobby Gillett > Sent: Monday, January 28, 2013 2:05 PM > To: [email protected] > Subject: Concealed Space - compsite wood joists > > > > NFPA 13 – 2010: > > 8.15.1.2.6* <http://codesonline.nfpa.org/a/c.ref/ID00001327787/sec> > Concealed spaces formed by ceilings attached to composite wood joist > construction either directly or onto metal channels not exceeding 1 in. > (25.4 mm) in depth, provided the joist channels are firestopped into volumes > each not exceeding 160 ft3 (4.53 m3) using materials equivalent to the web > construction and at least 3 1/2 in. (90 mm) of batt insulation is installed > at the bottom of the joist channels when the ceiling is attached utilizing > metal channels, shall not require sprinkler protection. > > 8.15.1.2.7 Concealed spaces entirely filled with noncombustible insulation > shall not require sprinkler protection. > > 8.15.1.2.8 Concealed spaces within wood joist construction and composite > wood joist construction having noncombustible insulation filling the space > from the ceiling up to the bottom edge of the joist of the roof or floor > deck, provided that in composite wood joist construction the joist channels > are firestopped into volumes each not exceeding 160 ft3 (4.53 m3) to the > full depth of the joist with material equivalent to the web construction, > shall not require sprinkler protection. > > > > I have a concealed space formed by composite wood joists with ceiling > attached directly to the bottom of the joist (no metal channels, so > insulation is not a requirement). If I’m not mistaken, in order to consider > it a space that doesn’t require sprinkler protection I have to do the > following: > > Per 8.15.1.2.6 – Have the joist channels firestopped into volumes not > exceeding 160 ft³ OR > > Per 8.15.1.2.7 – Completely fill the space with noncombustible insulation OR > > Per 8.15.1.2.8 - Completely fill the space with noncombustible insulation > AND have the joist channels firestopped into volumes not exceeding 160 ft³ > (WHICH KICKS 8.15.1.2.7 OUT FOR COMPOSITE WOOD JOISTS ALTOGETHER) > > > > I guess what I am misunderstanding is if I have to firestop the joist > channels into volumes not exceeding 160ft³ either way, why would we want to > fill the joist space completely with noncombustible insulation? Only thing I > could think of would be to keep from having to do a 3000ft² RA in the > adjacent protected space. > > > > Any comments for my understanding would be appreciated. > > > > Bobby Gillett > _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum
