1011.9 Curved stairways.
BC § 1011.9
Curved stairways with winder treads shall have treads and risers in accordance with Section 1011.5 and the smallest radius shall be not less than twice the minimum width or required capacity of the stairway, whichever is greater. Exception: The radius restriction shall not apply to curved stairways in Group R-3 and within individual dwelling units in Group R-2.













