The required degree of fire resistance-rated separation for an exit stair enclosure depends on?

The required degree of fire resistance-rated separation for an exit stair enclosure is primarily dependent on the number of stories or floor levels the exit stair connects. This is because as the height of the building increases, the potential for fire spread and the necessary safety measures to protect egress routes also increase.

Stairs that serve multiple levels need to be adequately protected to ensure that occupants can safely evacuate during an emergency. The fire resistance rating of the enclosure is designed to provide sufficient time for evacuation and to prevent smoke and flames from entering the stairwell, thus facilitating a safe horizontal or vertical evacuation.

While the height of the building and the type of occupancy can influence building codes and safety regulations, the direct relationship between the fire protection requirements and the number of stories ensures that stair enclosures meet the specific challenges posed by taller structures in terms of fire safety and occupant protection.