What Roland says, and to clarify: The interstitial space above the envelope is combustible concealed and the compartments below the ceiling are what they are. If it's a rated building (we typically see this condition in buildings that were Type V-1 hour under the UBC and Type V-A under the IBC), then the space between the suspended ceiling and the envelope is the one considered non-combustible.
Keep in mind though that if it's to be used as a plenum, that triggers a bunch of other requirements such as dampers and detection that, if not provided, would trigger sprinklers in the plenum as well. Steve Leyton -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Roland Huggins Sent: Monday, August 05, 2013 1:08 PM To: [email protected] Subject: Re: Special Situations (8.15) but the wood is not encased but is simply attached to the bottom. As such, it is an enclosed combustible concealed space. So 8.15.1.2.2 does not apply. One has to dance with the remaining exemptions for combustible spaces. Roland Roland Huggins, PE - VP Engineering American Fire Sprinkler Assn. --- Fire Sprinklers Saves Lives Dallas, TX http://www.firesprinkler.org On Aug 5, 2013, at 11:52 AM, Ron Greenman <[email protected]> wrote: > So if the joisting is wood, but encapsulated by 5/8 type X GWB then > the assembly is still considered combustible? What if enough layers > (three I > think) to get a 2-hr rating? _______________________________________________ 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
