Wall bases can be both practical and aesthetically pleasing, providing a wall protection from damage or adding a distinctive architectural touch to an otherwise boring, flat plane. But, when it comes to accessibility, the wall base needs to be considered when measuring the clear width of an accessible route or the clear floor space at elements.
Since a wall base can mean an offset of an extra inch or so, a hallway that is designed to be 36” wide but has a wall base lining each side, might actually turn out to be about 34” wide after finishes are put in. The minimum footprint of a wheelchair—the measurement for clear floor space—is 30”x48”, so the critical measurement should be taken from the ground where the wheels will be.
This can also be important when designing for the minimum clear floor space at elements, such as in a drinking fountain alcove. The comment in the photo accounts for forward approach to the accessible fountain (and the water bottle filler), but it doesn’t account for the ¾” wall base. The 30” wide minimum requirement includes toe clearance.
Sometimes the basics of accessibility require a little extra thought about the realities of how a person might use something.