2010 ADA Standards for Accessible Design Pocket Guide
505.10.1 Top and Bottom Extension at Ramps.
Ramp handrails shall extend horizontally above the landing for 12 inches (305 mm) minimum beyond the top and bottom of ramp runs. Extensions shall return to a wall, guard, or the landing surface, or shall be continuous to the handrail of an adjacent ramp run. [S.H. 4.8.5(6)], [S.H. Fig. 17]