A. 
Every story used for human occupancy more than six stories above grade shall be provided not less than two independent exits. Every story used for human occupancy totally below grade greater than 2,000 square feet (186 square meters) shall be provided not less than two independent exits.
B. 
Exceptions. A single exit is acceptable when:
(1) 
The building is provided an automatic fire suppression system and an automatic fire alarm system with smoke detectors located in all corridors, lobbies and common areas;
(2) 
The building is provided an automatic fire alarm system and the exit is a smokeproof enclosure or pressurized stairway; or
(3) 
An existing fire escape or slidescape conforming to the building code is provided in addition to the single exit.
All interior exits shall be enclosed with approved assemblies except as provided in the following table:
Enclosure Exceptions
Building Use Group
Exception Conditions*
Business
When connecting not more than 2 floor levels and less than 3,500 square feet per floor
When connecting not more than 3 floor levels and the building is equipped with an automatic fire suppression system
Education
When connecting not more than 2 floor levels and the building is equipped with an automatic fire suppression system
Factory-industrial, storage
When connecting not more than 2 floor levels
When connecting not more than 3 floor levels and the building is equipped with an automatic fire suppression system
Mercantile
When connecting not more than 2 floor levels and less than 2,000 square feet per floor
When connecting not more than 2 floor levels and the building is equipped with an automatic fire suppression system
Residential, hotels
When connecting not more than 2 floor levels and the building is equipped with an automatic fire suppression system
Residential, apartment
When connecting not more than 2 floor levels with not more than 4 dwelling units per floor
When connecting not more than 3 floor levels with not more than 4 dwelling units per floor and the building is equipped with an automatic fire suppression system
Residential one- and two-family dwellings
In every case
*NOTE: One square foot = 0.093 square meters.
Enclosures connecting not more than six floor levels shall have a fire-resistance rating of not less than one hour with approved opening protectives. Enclosures connecting more than six floor levels shall have a fire-resistance rating of not less than two hours with approved opening protectives.
The capacity of the exits serving a floor shall be sufficient for the occupant load thereof as determined by the building code.
All corridors serving an occupant load of greater than 30 and openings thereof are to provide an effective smoke barrier. All transoms, louvers, doors and other openings are to be closed or be self-closing.
A. 
All corridors which serve more than one exit shall provide direct connection to such exits. The length of a dead-end corridor shall not exceed 35 feet (10,668 millimeters).
B. 
Exception. The dead-end travel distance limit shall be increased to 70 feet (21,336 millimeters) when the building is equipped with an automatic fire alarm system.