10. Clearances

10.1 Main evacuation staircase

The control towers have a staircase with 2 passage units (UP) serving at least the bottom level of the last compartment. This staircase can accommodate a stretcher.

This staircase is either enclosed or open-air. To be considered open-air, at least 50% of each flight of stairs must communicate with the outside.

The staircase serving the upper floors is continuous up to the level allowing evacuation to the outside or to a passageway leading directly to the outside.

The stairwells serving the upper floors and basements are interrupted at the evacuation level.

No premises open directly onto the main evacuation staircase. Any communications are via an intercommunication...