ADA 101 – Curb or Barrier Edge Protection
2010 ADAS 405.9.2 Curb or Barrier Edge Protection
A curb or barrier shall be provided that prevents the passage of a 4 inch diameter sphere, where any portion of the sphere is within 4 inches of the finish floor or ground surface.
Code according to 2010 ADAS. Check your state’s accessibility laws. Some states such as California, Georgia and Florida have additional requirements and standards.