Tactile tile warning strips

The Americans with Disabilities Act (ADA), passed in 1990, required the establishment of design criteria for building and altering commercial and public facilities, including sidewalks and curb ramps. In 1991, the U.S. Department of Transportation (USDOT) and the U.S. Department of Justice (USDOJ) developed a set of regulations for new construction and alterations. The regulations include standards that reference the ADA Accessibility Guidelines for Buildings and Facilities (ADAAG), developed by the U.S. Access Board-an independent Federal agency devoted to accessibility for people with disabilities. The guidelines require the installation of detectable warnings on sidewalks, street crossings and curb ramps, hazardous vehicular ways, and transit platform edges.

Currently, the draft guidelines for public rights-of-way, published in June 2002, describe detectable warnings as a surface of truncated domes arranged in a square grid pattern. The domes need to have a base diameter of 23 to 36 millimeters (0.9 to 1.4 inches), a top diameter of 50 to 65 percent of the base diameter, and a height of 5 millimeters (0.2 inch). Dome center-to-center spacing is allowed in the range of 41 to 61 millimeters (1.6 and 2.4 inches) and a base-to-base spacing of at least 16 millimeters (0.65 inch), measured between the most adjacent domes on the square grid. Detectable warnings also need to contrast visually with adjoining surfaces, either light-on- dark or dark-on-light. The surface of the detectable warnings must be 61 centimeters (24 inches) by the width of the curb ramp.

Tactile tile detectable warning strips are used to frame a tile and provide unmistakable visual contrast between the tile and the surrounding surface.  A 3 inch strip is installed around the tile to ensure a visual contrast.

For more information on Tactile tile detectable warning strips and other detectable warning systems visit www.armor-tile.com .

By John Heffner

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