The Americans with Disabilities Act (ADA) is a groundbreaking civil rights document, allowing disabled persons to experience the same opportunities of mainstream life enjoyed by all Americans. A large part of experiencing mainstream American life is being able to safely enjoy public spaces. The ADA became law in 1990, affording Americans with disabilities similar protections against discrimination to the protections articulated by the Civil Rights Act of 1964.
The ADA requires public accommodation and services operated by private entities to comply with accessibility standards by making reasonable alterations to the building, and its surrounding areas to include detectable warning systems.
ADA detectable warnings are required in many areas of public spaces such as pedestrian crossings, escalator approaches, curb ramps, transit platforms, parking areas, stair landings and many more.
Detectable warning products, such as truncated domes, have been designed to be felt comfortably through shoes as a way to alert those with visual impairments of any potential upcoming dangers, such as a curb drop or entry into a traffic roadway.
What are Detectable Warning Systems?
Detectable warnings, or tactile panels, are comprised of truncated domes. These bumps, which can either be installed individually or together on a tile or detectable warning pad, are large enough to be felt underfoot or detected with a walking cane yet small enough as to not create any tripping hazards.
Truncated dome tiles also sport an audible detection feature. When using a guidance cane, the appearance of truncated domes make an audible noise, marking a distinct audio difference between the sidewalk and the ADA detectable warning.
Further adding another level of detectability, tactile panels and detectable warning systems are required by the ADA to provide a stark visual contrast. This means if the ADA tiles are being applied on a light surface, the truncated domes must be a darker color or vice versa.
Making Your Space ADA Compliant with Tactile Panels
There are a variety of factors determining the compliance of an ADA detectable warning. Firstly, it is critical for ADA compliance that truncated domes are aligned in a square or radial grid pattern.
Some of the most important aspects of ADA detectable warnings are dome size, dome spacing, contrast, area size and location and alignment.
Truncated Dome Size
To provide ADA compliance, truncated domes within detectable warning systems must be large enough to be easily detected, yet small enough to eliminate tripping hazards and other potential dangers.
The ADA requires truncated domes to have a minimum base diameter of 23 mm (0.9 in) and shall not exceed 36 mm (1.4). The top diameter of the dome shall be a minimum of 50 percent of the base diameter, and shall not exceed 65 percent.
Each truncated dome shall extend above the surface of the sidewalk, or detectable warning panel, a maximum of 5mm (0.2 in).
Truncated Dome Spacing
Having the correct spacing between truncated domes allows for accessibly for wheelchairs and strollers, without losing the effectiveness of detectable warning products.
Per the ADA, truncated domes are required to have a minimum center-to-center spacing of 41 mm (1.6 in). The center-to-center spacing shall not exceed 61 mm (1.6 in). The base-to-base spacing between truncated domes shall be 17 mm, or less than, (0.65 in) when measured between the most adjacent domes.
ADA detectable warnings are required to provide a stark visual contrast between the tactile panel itself and the surrounding area. Either light-on-dark or dark-on-light provide the greatest visual contrast.
Detectable warning products are designed to alert pedestrians of any potential dangers, and to do so must give an advanced warning. The ADA requires that tactile panels extend a minimum of 610 mm (24 in) in the direction of travel. Further, an ADA detectable warning panel should cover the full width of the curb ramp, not including flares. The truncated dome tile should also cover the full width of a landing or blended transition.
Location and Alignment
ADA curb ramp requirements state perpendicular curb ramps are required to have a detectable warning on the surface at the bottom of the grade break or the lower land. Landings and blended transitions require detectable warning systems located on the landing or blended transition at the back of curb.
In all applications, truncated domes within detectable warning products are required to align perpendicular or radial to the grade break between the ramp, landing or blended transition and the street.
Access® Tile has meticulously designed an entire product line of detectable warning systems dedicated to enhancing the safety of public areas and making communities across America more accessible for people of all abilities.
This guide is not intended to be a comprehensive, official building code document. Learn more about ADA detectable warnings.