Required exit width for exit stairs that serve interconnected floor spaces designed in accordance with Articles 3.2.8.3. to 3.2.8.9., where the stairs provide not less than 0.3 m² of area of treads and landings for each occupant of the interconnected floor spaces, or protected floor spaces conforming to Article 3.2.8.6. are provided at each floor level and the protected floor space on a floor level has not less than 0.5 m² of space for each occupant of that floor level of the interconnected floor space.

This applies to buildings described in Sentence 1.3.3.2.(1) of Division A that contain portions of a floor area or mezzanines that do not terminate at an exterior wall, a firewall or a vertical shaft, and are required in Clause 3.2.8.1.(1)(b) to be protected in conformance with Articles 3.2.8.3. to 3.2.8.9.

This also applies to:

• exit stairs in an assembly hall or theatre serving more than one balcony level, as stated in Sentence Sentence 3.4.3.2.(5),
• tents and air-supported structures, as stated in Sentences 3.1.6.1.(1) and 9.10.1.2.(1), and
• buildings to which Part 9 applies [see Sentence 1.3.3.3.(1) of Division A for application of Part 9], where there are openings through floors that are not protected by shafts or closures, as stated in Sentence 9.10.1.2.(6).

Exceptions: 

To supersede the requirement in the first part of Sentence 3.4.3.2.(6) that exit width be cumulative on the basis that an intermediate area of safety is provided that allows persons to be protected from the hazards of the interconnected floor space while queuing before entering an exit stair or while waiting to proceed in the exit stair.