protruding objects – avoiding hazards along the way

Posted on - Thursday, November 4th, 2010

When designing for accessibility, we immediately think of the wheelchair users and their needs.  We design the parking, accessible route, ramps and eliminate the architectural barriers that impede the wheelchair access to the building or site. But the ADA involves more than mobility disabilities. The rules that people are not so aware of deal with the visually impaired community. The way we design for the blind and low vision patrons make it easier for way finding and getting around avoiding hazards along the way. 

The new ADA keeps most of these rules intact, except for adopting a new numbering system in the guidelines. The new section for protruding objects will be found in Section 307 Protruding Objects


Protruding Objects

In the 2004 version of the ADAAG, the rules describe objects that protrude onto the circulation path of travel (not the accessible route).  This path is different than an “accessible route”. The path of travel is for all pedestrians, regardless of disability. Along the circulation path, there should not be any protrusions that would cause a hazard to people who are visually impaired and wouldn’t normally see the protruding object.  These requirements are now found in section 307 (formally 4.4)

Wall mounted and free standing objects that are mounted above 27″ cannot be detected by a person who uses a cane to find their way around. So any object that is mounted on the wall along the circulation path (remember this is a pedestrian route, not a wheel chair route) have to maintain a path free of obstructions

This photo shows a drinking fountain on the way to the restroom and higher than 27″ a.f.f. which would be a hazard to a blind person


A person who is visually impaired will not detect objects that are lower than 80″ from the ground.  Objects along the circulation path, such as open stairs, sconces, even branches of a tree, should have some warning at a cane detectable height in front of it in order to warn the visually impaired person that a hazard may be up ahead  


This open stair is a hazard since there is no way to detect the lower portion. 

safety zone

This graphic shows exterior elements that could become
hazards if they are not cane detectable.

Inspector’s Corner

The 2004 version of the ADAAG eliminates the detectable warnings at curb ramps.  No longer will the truncated dome texture and contrasting color will be required within the property line. The Access Board and the Department of Transportation will be developing guidelines for curb ramps in the public right of way.  We will keep you posted.


Detectable warnings are a controversial topic for architects but also for the disabled community.  Visually impaired people really like detectable warning, like truncated domes, because it helps them with way finding.  However architects and builders get frustrated with all their inconsistencies.  Wheel chair users don’t enjoy the high maintenance that it requires at curb ramps.  If the ramp ices over, it can gather dirt,and it is hard to wheel around it.  So even though the detectable warnings at curb ramps were removed, the controversy in the disabled community has not gone away

This is an example of how a curb ramp can accumulate dirt and ice so that it can become a hazard more than a help