2019 California Standards for Accessible Design Guide (effective January 1, 2020 with July 1, 2021 amendments)

11B-703.2.5 Character height.

Character height measured vertically from the baseline of the character shall be 5/8 inch (15.9 mm) minimum and 2 inches (51 mm) maximum based on the height of the uppercase letter “I”.

Exception: Reserved. 

[2010 ADA Standards] EXCEPTION: Where separate raised and visual characters with the same information are provided, raised character height shall be permitted to be ½ inch (13 mm) minimum.

FIGURE 11B-703.2.5 HEIGHT OF RAISED CHARACTERS