Tactile characters and braille: the numbers in §703

A tactile sign is read twice: by eye, and by fingertip. Section 703 of the 2010 ADA Standards sets the dimensions that make both work. Here are the numbers, taken from the Standards and the U.S. Access Board's guide to them.

Raised characters (§703.2)

• Raised at least 1/32 inch from the background.
• Uppercase only, in a sans serif style. No italic, oblique, script or highly decorative forms.
• Between 5/8 inch and 2 inches tall, measured on the uppercase I.
• Stroke thickness of the uppercase I no more than 15% of the character height. Where the raised characters also serve as the visual ones, the Access Board recommends at least 10%.
• Uppercase O between 55% and 110% as wide as the I is tall.
• At least 1/8 inch between characters, and no more than four times the stroke width.
• Lines spaced 135% to 170% of the character height, baseline to baseline.

Our builder sets raised lettering in a condensed sans serif that stays inside these limits, at 5/8 inch for room names and 7/8 inch for room numbers, with lines at 150%.

Braille (§703.3)

Braille must be contracted, also called Grade 2, and the Access Board notes that Unified English Braille is acceptable. It goes directly below the raised text it repeats. Where the text runs to several lines, the braille goes below the whole block. There must be at least 3/8 inch between the raised characters and the braille, and between the braille and any raised border or decoration. The dots themselves have tight tolerances:

• Dot base diameter 0.059 to 0.063 inch, dot height 0.025 to 0.037 inch.
• 0.090 to 0.100 inch between dots in a cell, and 0.241 to 0.300 inch between corresponding dots in neighboring cells.
• 0.395 to 0.400 inch between corresponding dots in cells on separate lines.

Capital letters in braille are used only for the first word of a sentence, proper nouns and names, individual letters, initials and acronyms. The builder's braille leaves capital indicators out, which is right for most room names. If a sign names a person or uses an acronym, add the capital indicators when you proofread. Every sign on this site shows its braille as Unicode below the preview for exactly that reason.

Pictograms (§703.6)

A pictogram that names a permanent room, such as the figures on a restroom sign, sits in a field at least 6 inches high. The field is measured, not the figure, and nothing else goes inside it. The room's name in raised characters and braille, called the text descriptor, goes directly below the field. The pictogram itself doesn't need to be raised. Informational symbols like the International Symbol of Accessibility don't need the field or a descriptor.

Finish and contrast

Characters and their background need a non-glare finish and contrast, either light characters on a dark background or dark on light. The Standards set no minimum contrast value and no required colors, so blue, black, gray, green, brown, burgundy, red and white fields are all available in the builder. Braille is exempt from the finish and contrast rules.

The downloads here are artwork. A compliant tactile sign also needs real raised characters and domed braille, so take the file to a sign fabricator, and proofread the braille before it's made.