Seems to me that the purpose of filled am otherwise combustible concealed space with a non-combustible material is to displace oxygen and so remove a leg of the triangle, or a facet of the tetrahedron if you prefer solid geometric models. Since the concealed space is already combustible due to the wood trusses, the addition of a layer of kraft paper sandwiched between a non-combustible batt and non-combustible blown in insulation will not spontaneously combust and burn on it's own. I can't think of why the AHJ would consider displacement of oxygen to work on keeping the wooden trusses from burning but not the paper.
On Tue, Jun 30, 2015 at 6:14 AM, Scott A Futrell <[email protected]> wrote: > Matt, > > Yes, that is basically it. Wood trusses, so bottom of trusses (ceiling) > has the batt insulation, paper up. We want to blow full of non-combustible > insulation and not remove the paper-backed stuff. It is a very large area, > two accesses only, and a laborer would have to crawl through and remove it > all. Well, even to blow it full additional access locations would be > necessary, but not as many as if that all has to come out. > > Scott > > Office: (763) 425-1001 x 2 > Cell: (612) 759-5556 > > -----Original Message----- > From: Sprinklerforum [mailto: > [email protected]] On Behalf Of Matt Grise > Sent: Tuesday, June 30, 2015 7:52 AM > To: [email protected] > Subject: RE: Insulation and combustible concealed ceiling space > > Am I picturing this correctly? > > A lower level of wood 2x's with bat insulation directly on them (paper > up), then laid on top of the paper (up to the top of the space) is > blown-in insulation? > > If the paper is fully contained inside non-combustible insulation. > > 1 - It seems unlikely that the paper could catch on fire or propagate fire > across it. > 2 - this seems like the same idea that lets you exclude the rest of the > combustibles (if the combustible surfaces are completely covered - then > there are no exposed combustibles) > > You could call it 2 separate combustible concealed spaces - one space > below the paper, one space above the paper. Both spaces are completely > filled with non-combustible insulation. > > Matt Grisé PE*, LEED AP, NICET II > Sales Engineer > Alliance Fire Protection > 130 w 9th Ave. > North Kansas City, MO 64116 > > *Licensed in KS & MO > > 913.888.0647 ph > 913.888.0618 f > 913.526.7443 cell > www. AFPsprink.com > > > -----Original Message----- > From: Sprinklerforum [mailto: > [email protected]] On Behalf Of Scott A > Futrell > Sent: Tuesday, June 30, 2015 7:34 AM > To: [email protected] > Subject: Insulation and combustible concealed ceiling space > > Has anyone ever had an issue with a combustible concealed space that has > one layer of kraft-faced batt insulation laying on the ceiling (kraft side > up toward the sky) and then the remainder filled full of blown-in, > non-combustible insulation and an AHJ saying the kraft-faced insulation had > to be removed? Or, conversely that the kraft-faced was acceptable. This > is fiberglass batt insulation, standard thickness for joists/studs with > kraft backing. > > I’d really like to hear arguments for 1) having to remove the kraft-faced > and why, and 2) leaving it in place and why. I want to leave it in place. > > Thanks! > > Scott Futrell > > > > _______________________________________________ > 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 > -- Ron Greenman Instructor Fire Protection Engineering Technology Bates Technical College 1101 So. Yakima Ave. Tacoma, WA 98405 [email protected] http://www.bates.ctc.edu/fireprotection/ 253.680.7346 253.576.9700 (cell) Member: ASEE, SFPE, ASCET, NFPA, AFSA, NFSA, AFAA, NIBS, WSAFM, WFC, WFSC They are happy men whose natures sort with their vocations. -Francis Bacon, essayist, philosopher, and statesman (1561-1626) A problem well stated is a problem half solved. -Charles F. Kettering, inventor and engineer (1876-1958) _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
