ADA Focus: Detectable Warnings

11 November, 2012 UniversalDesignStyle

705 Detectable Warnings

705.1 General. Detectable warnings shall consist of a surface of truncated domes and shall comply with 705.

705.1.1 Dome Size. Truncated domes in a detectable warning surface shall have a base diameter of 0.9 inch (23 mm) minimum and 1.4 inches (36 mm) maximum, a top diameter of 50 percent of the base diameter minimum to 65 percent of the base diameter maximum, and a height of 0.2 inch (5.1 mm).

705.1.2 Dome Spacing. Truncated domes in a detectable warning surface shall have a center-to-center spacing of 1.6 inches (41 mm) minimum and 2.4 inches (61 mm) maximum, and a base-to-base spacing of 0.65 inch (17 mm) minimum, measured between the most adjacent domes on a square grid.

705.1.3 Contrast. Detectable warning surfaces shall contrast visually with adjacent walking surfaces either light-on-dark, or dark-on-light.

Figure (a) is an enlarged elevation drawing of a single dome showing the base diameter as 0.9 to 1.4 inches (23 to 36 mm) and the top surface as having a diameter of 50% to 65% of the bas. The dome height is 0.2 inch (5.1 mm). Figure (b) is a plan view of a detectable warning surface showing the center-to-center dome spacing of 1.6 to 2.4 inches (41 to 61 mm) with a base-to-base separation of 0.65 inch (17 mm) minimum.

Figure 705.1 Size and Spacing of Truncated Domes