What are the requirements for the doors of the smoke-proof stairwell and its front room?

The doors of the smoke-proof stairwell and its front room shall be Class B fire doors.

Smoke staircase settings:

(1) On the plane layout, a front room adjacent to the external wall is set, and windows with an opening area of not less than 2m2 are set on the external wall, which can be closed at ordinary times, but all windows should be opened in case of fire.

(2) The doors entering the front room from the walkway and the doors entering the stairwell from the front room must be Class B fire doors, which should be closed at ordinary times and in case of fire.

Requirements and functions:

(1) According to the specification requirements, the smoke-proof stairwell and the fire elevator shall be provided with front halls.

(2) The function of the front room of the smoke-proof stairwell is to prevent fire smoke from entering the stairwell.

(3) The function of the front room of the fire elevator is to prevent the fire smoke from harming the firefighters who enter the fire floor through the fire elevator for fire fighting and search and rescue.

(4) The smoke-proof stairwell and the fire elevator share the front room, which has the above two functions.

(5) Evacuation stairs are used for personnel evacuation in case of fire.

(6) The combination of front chambers means that the above two front chambers are combined into one front chamber, which increases the area requirement.