1029.13.2.2 Risers.
BC § 1029.13.2.2
Where the gradient of stepped aisles is to be the same as the gradient of adjoining seating areas, the riser height shall be not less than 4 inches (101.6 mm) nor more than 8 inches (203.2 mm) and shall be uniform within each flight. Exception: Riser height nonuniformity shall be limited to the extent necessitated by changes in the gradient of the adjoining seating area to maintain adequate sightlines. Where nonuniformities exceed 3/16 inch (4.8 mm) between adjacent risers, the exact location of such nonuniformities shall be indicated with a distinctive marking stripe on each tread at the nosing or leading edge adjacent to the nonuniform risers. Such stripe shall be not less than 1 inch (25.4 mm), and not more than 2 inches (50.8 mm), wide. The edge marking stripe shall be distinctively different from the contrasting marking stripe.
