I'm trying to determine the exterior wall rating for a non-separated mixed use, 1A building and it's been a while. The uses include S-2, R-1, R-2, M and A-2. For example, if the FSD was 8ft, would the rating need to be 2 hour (required for M) regardless of the use present at that part of the building (A, R and S-2 only require 1 hour)?