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Raised Tactile and Braille Signage

  • May 1, 2012
  • Bruce Bromley

Raised Tactile and Braille SignageWe are often asked to assess signage against the requirements of the Disability Access to Premises Standard and Australian Standard AS1428.1 Design for access and mobility – General requirements for access – New building work and it is rare to find ones that fully comply.

When auditing a sign, the following are the key items are checked.

  1. Tactile characters must be raised or embossed to a height of not less than 1 mm and not more than 1.5 mm.
  2. Upper case tactile characters must have a height of not less than 15 mm and not more than 55 mm.
  3. Lower case tactile characters must have a height of 50% of the related upper case characters. *
  4. Tactile characters, symbols, and the like, must have rounded edges.
  5. The entire sign, including any frame, must have all edges rounded (Not just corners).
  6. The surface of the sign must be continuous for hygiene purposes.
  7. Signs must be constructed so as to resist the removal of letters and Braille dots by picking or adhesive failure.
  8. The background, negative space or fill of signs must be of matt or low sheen finish.
  9. The characters, symbols, logos and other features of signs must be matt or low sheen finish.
  10. The minimum letter spacing of tactile characters on signs must be 2 mm.
  11. The minimum word spacing of tactile characters on signs must be 10 mm.
  12. Fonts with letters of constant stroke thickness must be used.
  13. The thickness of letter strokes must be not less than 2 mm and not more than 7 mm.
  14. Tactile text must be left justified, except that single words may be centre justified
  15. Braille must be raised and domed.
  16. Braille must be located 8 mm below the bottom line of text (not including descenders).
  17. On signs with multiple lines of text and characters, a semi-circular Braille locator at the left margin must be horizontally aligned with the first line of Braille text. **

*     It is our opinion this requirement is flawed as Arial typeface is copyright and under it’s usage license cannot be modified. In addition having lower case letters that are smaller than standard creates an issue with the weights of the lower case letters.

**    The semi circular Braille should not be used when a single line of Braille is used. This is covered both within the BCA & AS1428.1-2009.

AS 1428.1—2009
NOTES:

1 The Braille indicator is only used where there are multiple lines of text. It indicates the location of the first line of Braille.

BCA D3.6 part 6
(f)    On signs with multiple lines of text and characters, a semicircular braille locator at the left margin must be horizontally aligned with the first line of braille text.

The physical specifications for Braille dots and the distance between them shall be as follows:

  1. 2.29-2.50mm for the horizontal distance between dots within a cell;
  2. 2.29-2.54mm for the vertical distance between dots within a cell;
  3. 6.00-6.10mm for the horizontal distance between corresponding dots in adjacent cells;
  4. 10.16-10.41mm for the vertical distance between corresponding dots in adjacent lines;
  5. 1.40-1.50mm for the dot base diameter;
  6. 0.46-0.53mm for the dot height; and
  7. 0.76–0.80mm for the spherical radius of dots.

Note I: within cells the horizontal distance between dots must always be less than or equal to the vertical distance between them.

Note II: Braille dots should be smooth and pleasant to touch.  Therefore, dots must be dome shaped, rather than being pointy or flat.  Note that the spherical radius is a function of the base diameter and the height of dots, not an independent parameter.