Knee and Toe Clearance measurements pertain to people in a wheel chair making an entry way into an object. So what that entails is that a disabled person’s knees and feet have room to move forward to an object, like a stool or a big box. But, not every object will allow these movements. When the objects that they can move around with are stationary, they are restricted.
The best thing to do, when having to make a forward reach, is to find something that does not involve bending over, and to move into that space. This will keep them from having to bend their knee in order to move one step forward, and it will also keep them from impeding their walk by keeping their feet from being in front of the curve in the ground, where they might fall. In order to do this, the person in the chair will want to sit at a point where they have the least amount of curve in their spine. Usually, for a normal sized adult, this is right around chin level, although some will have more curve than that. In order to find out where the minimum required curve is, just measure from the tip of the nose to the base of the spine, and that is the minimal spine curve you will need.
If you are looking for a set guide, then you should know that there are several different ones that are used to help people in wheelchairs find the proper clearance. These guides show different minimum clearance levels and will be broken down into specific situations. For example, if you are required to make a full motion turn, then the guide will show you the maximum that your walk style will allow and the minimum needed. The figures are usually shown in inches. This way, if you are unsure what is the minimum, you can simply look up that number on the guide and see what happens.