OK HB3913

Municipalities may authorize apartment buildings with a single stairway if they meet specific criteria, regardless of local International Building Code amendments

Single-stairway buildings are limited to six stories maximum above grade plane, with no more than four dwelling units per floor

Required fire safety features include automatic sprinklers in stairways per NFPA Standard 13, two-hour fire-rated stairway enclosures, and one-hour fire-rated corridors from unit doors to exits

Maximum distance of 20 feet required between dwelling unit doors and exit stairways, with 125 feet maximum exit access travel distance

Automatic smoke and fire detection systems required in common spaces, laundry rooms, mechanical rooms, storage rooms, corridors, and stairway landings; effective November 1, 2026