Clear dimension
Doors and entries should be designed with enough space (clear dimension) for person traffic and to allow passage in a wheel chair. Even other openings in transfer routes shall be designed so as to allow passage in a wheel chair. Applicable standards and requirements should be taken into account. In escape routes the regulations regarding the opening dimensions must be adhered to as well.
Rebate door

A = Clear Dimension
B = Frame outside dimension
C = Wall opening
D = 115 mm