Final answer:
Exit routes must be at least 15 inches wide at all points and could be as deep as 15 diameters.
Step-by-step explanation:
The exit routes must be at least 15 inches wide at all points.
According to an old "rule of thumb", exit routes needed to be 5 side-to-side and 7-8 deep. However, newer research suggests that exit routes should be as much as 8 diameters side-to-side and 15 diameters deep.