Corridor walls shall extend from the top of the foundation or floor below to one of the following:
- The underside of the floor or roof sheathing, deck or slab above.
- The underside of a ceiling above where the ceiling membrane is constructed to limit the passage of smoke.
- The underside of a lay-in ceiling system where the ceiling system is constructed to limit the passage of smoke and where the ceiling tiles weigh not less than 1 pound per square foot (4.88 kg/m2)of tile.