The Passive Fire Protection Handbook: Chapter 5 - Partitions and External Walls

Depending upon its situation and function within a building, a wall may be expected to fulfil different requirements in the event of fire. Fire resisting walls used for partitioning buildings and enclosing compartments will be required to provide a barrier to the passage of fire from one side or the other and must therefore be able to satisfy each of the relevant criteria (integrity, insulation and if the wall is loadbearing - loadbearing capacity) from either side for the prescribed period.