Building Code Guides (BCGs) and Building Official Determinations (BODs) provide answers about the application of building codes and outline optional alternates. BODs are typically smaller in scope and address simpler questions. Code Guides provide a comprehensive alternative to a complicated set of code requirements.
BOD 19-01: Supporting construction for fire rated horizontal separations
QUESTION: Does an exterior bearing wall supporting a fire rated horizontal separation always need to be rated for exposure to fire from both sides?
RESPONSE: Where bearing walls are only fire rated because they are supporting a fire rated horizontal assembly per R302.3.1, if the walls “fire separation distance is more than 3’ (whether that is an actual property line or an assumed property line between buildings on the same lot), fire protection may be provided by a wall assembly that was tested from the interior only. If the floor above projects to a fire separation distance that is less than 3’ then the exterior bearing wall supporting fire rated horizontal separations shall be rated from both sides.
HISTORY: Implemented February 20, 2019
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