Limits of Protruding Objects
[US Access Board]
When most people think about accessible design, the first thing that comes to mind is designing for people in wheelchairs. However, there’s a lot more to it than that. Requirements in federal, state, and local accessibility laws and codes account for a wide range of disabilities, including vision impairments. One of the most important design considerations for people with vision impairments is eliminating projections into the circulation path. Objects projecting from walls or other fixed elements can pose a hazard if they do not meet certain requirements. Any object that extends more than 4 inches into the circulation path between 27 and 80 inches above the finished floor is considered a protruding object
and must be protected by a fixed cane detectable barrier installed below the object.
There are many ways to provide adequate protection at protruding objects and our accessibility consultants are always keeping an eye out for accessible design solutions that look like they were an intentional part of the design, rather than an afterthought. Here are just a few of the more successful and aesthetically pleasing examples of cane detectable barriers that we have come across…
Drinking fountains are common protruding objects found along circulation paths. Installing fountains in an alcove or providing a fixed barrier with the bottom edge located no more than 27 inches above the floor to one side of the fountain are possible solutions.
The drinking fountains are located in an alcove.
A fixed barrier is provided to the side of the fountain that is mounted more than 27 inches above the floor.
Below open stairs, headroom clearance will be reduced to less than the required 80 inches AFF. To provide headroom protection where the vertical clearance below the open stairs is less than 80 inches, a barrier must be installed.
The stair handrail folds down and wraps around the stair, functioning as a cane detectable barrier. [Emerson College, Los Angeles]
A curved bench serves as both a cane detectable barrier and a functional design feature. [Apple Store, Boston]
A rail provides a barrier where the vertical clearance is less than 80 inches. [Apple Store, London]
Cantilevered countertops with the bottom edge of the counter mounted more than 27 inches AFF are another common protruding object. This condition can frequently be found at bars, drink ledges, and counter seating, as well as amenity kitchen islands and peninsulas.
The countertop projects more than 4 inches into the circulation path, posing a hazard to a person with a vision impairment.
A metal strap has been wrapped around the projecting countertop to serve as a cane detectable barrier.
A waterfall countertop serves as a cane detectable barrier.