Party Walls

The Reasons Behind the Requirements

Written by Theresa D’Andrea, Accessibility Specialist

This month, several members of the Accessibility Team had the unique opportunity to experience navigating architectural barriers commonly faced by people who use wheelchairs. We attended a seminar held in New Jersey that involved actually getting into a wheelchair and going through a series of obstacles to experience just how challenging it is to navigate environments that do not meet (or just barely meet) the minimum standards of accessibility compliance. The experience of using a wheelchair to negotiate common obstacles brought to light the rationale behind accessible design and construction requirements that we deal with on a daily basis.

We were first presented with the seemingly simple task of negotiating vertical level changes of ¼ inch and ¾ inch, which are common at thresholds and other transitions found along circulation paths. While the majority of the class had little to no difficulty moving over the ¼ inch level change, only two of approximately 50 participants were able to negotiate the ¾ inch level change. Most of us could do little more than spin our wheels against it. Accessibility regulations prohibit a level change of greater than ½ inch (with a 1:2 max bevel) unless ramped (with a 1:12 max slope), and it was very easy to understand why after performing the exercise. The difference between a ¼ and ¾ inch change in level may have seemed rather insignificant to the eye, but when attempting to cross it in a wheelchair, that additional ½ inch became insurmountable.


Jenn Barrett, Accessibility Specialist, negotiating a ramp with a 1:12 slope

The next task set before us was to negotiate across a series of ramps at various slopes. We went up a ramp with a 1:12 (8.33%) running slope – the maximum permitted by code – with a vertical rise of 3 inches. Maintaining the momentum needed to reach the top was no easy feat. Considering the fact that code permits a vertical rise of up to 30 inches at this slope, it was not difficult to imagine just how demanding it would be to reach the top of a technically compliant ramp.

We were then asked to move through a 90 degree turn with a clear width of 36 inches, the minimum width of an accessible route. Nearly the entire class needed to back up and reposition at the corner of the turn to avoid scraping the foot rest of the wheelchair against the base molding (the results of many unsuccessful attempts can be seen in the image below). This was a particularly interesting exercise, as our clients frequently question whether base molding matters when assessing clearances. Evidently, it does.


Carlos Sevillano, Accessibility Specialist



Theresa D’Andrea, Accessibility Specialist, opening a door without the required latch side clearance

Our final challenge was to approach and open a door, both with and without the minimum required latch side clearance. In order to open the door, we had to position the wheelchair at a slight angle to the door, reach forward to grasp the handle, and then open the door with one hand while simultaneously rolling the wheelchair backwards and positioning it to move through the doorway with the other. As we discovered, when the minimum latch side clearance is not provided you have to stretch across your knees to the reach the door handle, throwing the body’s center of gravity forward and putting yourself in danger of toppling out of the wheelchair. As a result, anyone without a longer than average arm span found it almost impossible to open the door when the latch side clearance was not provided. Even with the necessary clearances, because the door was equipped with a closing device, it was extremely difficult to open the door, move out of the way of the door swing, and negotiate through the doorway before the door closed onto the wheelchair.

The numbers in the building codes and accessibility regulations are just that – numbers. Experiencing the basis of those numbers and the human element behind them gives us a better understanding of why we are required to design a certain way, and maybe the motivation to go beyond the minimum requirements to make life just a little bit easier for as many people as possible.

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