2010 ADA Standards for Accessible Design Pocket Guide
303 Changes in Level
Where changes in level are permitted in floor or ground surfaces, they shall comply with 303.
EXCEPTIONS: 1. Animal containment areas shall not be required to comply with 303.
2. Areas of sport activity shall not be required to comply with 303.
Changes in level of ¼ inch (6.4 mm) high maximum shall be permitted to be vertical.
Changes in level between ¼ inch (6.4 mm) high minimum and ½ inch (13 mm) high maximum shall be beveled with a slope not steeper than 1:2.
Advisory 303.3 Beveled. A change in level of ½ inch (13 mm) is permitted to be ¼ inch (6.4 mm) vertical plus ¼ inch (6.4 mm) beveled. However, in no case may the combined change in level exceed ½ inch (13 mm). Changes in level exceeding ½ inch (13 mm) must comply with 405 (Ramps) or 406 (Curb Ramps).