The Americans With Disabilities Act calls out two different options for providing space for wheelchairs to turn around. The first and most common is the 60″ diameter turning circle. This is what code reviewers are generally looking for and should be evidenced in all rooms that are required to be accessible. In my experience you can use the circle 95% of the time. However if you can’t fit the 60″ circle you can also meet the turn around space requirements with a T-shaped turn. The T-shape is a 60″x60″ square with two 12″x24″ sections removed (see illustration).
Keep in mind that the required dimensions are finished clear dimensions and should be increased if you are looking at framing dimensions.