2013 California Standards for Accessible Design Pocket Guide

1132A.4.1 Thresholds. Thresholds at the primary entry and required exit doors shall be no higher than ½ inch (12.7 mm). Thresholds at secondary exterior doors, including sliding door tracks, shall be no higher than ³/₄ inch (19.05 mm). Changes in height at interior door thresholds (e.g., floor material changes at door thresholds) shall not exceed ½ inch (12.7 mm). Thresholds shall comply with the following:

1.      Thresholds with a change in height of not more than ¼ inch (6.35 mm) may be vertical.

2.      Thresholds with a change in height between ¼ inch (6.35 mm) and ³/₄ inch (19.05 mm) shall be beveled with a slope no greater than 1 unit vertical in 2 units horizontal (50-percent slope).