I need to design two 4 hour cmu firewalls (due to building area separation req'mts)for a four story, wood framed, assisted living building in Florida. Per FBC, a firewall must have "sufficient structural stability under fire conditions to allow collapse of the construction on either side without collapse of the wall." One fire wall will run parallel to the framing on either side, the other will have framing bearing on ledgers on one side only. I verifed with the local Building Official that a 4-hour cmu load bearing wall (UL901) can use the framing on either side to brace the wall. I'm assuming that if the framing burns on one side, it will simple drop away from the wall & not impart any additional forces on the wall. The architect wants to use breakawy clips, but I don't see how to do that and achieve adequate support for the framing members. Am I okay in my assumption that if the wood framing collapses on one side, it will not impact the wall? If not, what kind of forces should I design for? The architect wants an 8" wall if possible, which works for my asssumptions.
Thanks for any help!
Thanks for any help!
