Standard Lift:
Head Room: 12 inches
Side Room: 4 inches
Depth Into Room: Door Height plus 2 feet

Low Head Room:
Head Room: 6 inches
Side Room: 6 inches
Depth Into Room: Door height plus 3 feet

The inside face of the opening must be prepared with all members presenting a flush surface.  Nothing should be between the jams unless it is above the minimum headroom requirement and outside the required amount of side space.