R409.5.5 Visual Character Height
Height to Finish Floor or Ground From Baseline of Character: 1.0 m (3.3 ft) to less than or equal to 1.8 m (5.8 ft)
Horizontal Viewing Distance: less than 1.8 m (6 ft)
Minimum Character Height: 16 mm (0.625 in)
Horizontal Viewing Distance: 1.8 m (6 ft) and greater 
Minimum Character Height: 16 mm (0.625 in), plus 3.2 mm (0.125 in) per 0.3 m (one ft) of viewing distance above 1.8 m (6 ft)
Height to Finish Floor or Ground From Baseline of Character: Greater than 1.8 m (5.8 ft) to less than or equal to 
3.0 m (10 ft)
Horizontal Viewing Distance: less than 4.6 m (15 ft)
Minimum Character Height: 51 mm (2 in)
Horizontal Viewing Distance: 4.6 m (15 ft) and greater 
Minimum Character Height: 51 mm (2 in), plus 3.2 mm (0.125 in) per 0.3 m (12 in) of viewing distance above 4.6 m (15 ft)
Height to Finish Floor or Ground From Baseline of Character: greater than 3.0 m (10 ft)
Horizontal Viewing Distance: less than 6.4 m (21 ft)
Minimum Character Height: 75 mm (3 in)
Horizontal Viewing Distance: 6.4 m (21 ft) and greater
Minimum Character Height: 75 mm (3 in), plus 3.2 mm (0.125 in) per 0.3 m (12 in) of viewing distance above 6.4 m (21 ft)