I don't have a good argument, so I am going to go with you are not "in" the building so not required....The intent of the tenant separations are to keep a fire from spreading from unit to unit or from building in a unit and then blowing through to the next....The termination requirements for fire partitions typically allow them to stop at the exterior walls....
420.2 Separation walls. Walls separating dwelling units in
the same building, walls separating sleeping units in the same
building and walls separating dwelling or sleeping units from
other occupancies contiguous to them in the same building
shall be constructed as fire partitions in accordance with Section
708.4 Continuity. Fire partitions shall extend from the top of
the foundation or floor/ceiling assembly below to the underside
of the floor or roof sheathing, slab or deck above or to
the fire-resistance-rated floor/ceiling or roof/ceiling assembly
above, and shall be securely attached thereto. In combustible
construction where the fire partitions are not required to be
continuous to the sheathing, deck or slab, the space between
the ceiling and the sheathing, deck or slab above shall be fireblocked
or draftstopped in accordance with Sections 718.2
and 718.3 at the partition line. The supporting construction
shall be protected to afford the required fire-resistance rating
of the wall supported, except for walls separating tenant
spaces in covered and open mall buildings, walls separating
dwelling units, walls separating sleeping units and corridor
walls, in buildings of Type IIB, IIIB and VB construction.
Consider a BBQ fire on one side with the wind blowing?