Differential car doors/gates are used
when overhead is severly limited. Differential car doors/gates are 1830mm
(6 ft) high and consist of two equal height counteweighted panels and
can be either manually or power operated.
Required overhead height, measured from
the top landing sill to the nearest overhead obstruction, for a 1839mm
(6 ft) high differential door/gate is equal to the landing door opening
height plus 1000mm (3 ft 3 in). Differential car doors/gates 1839 mm (6
ft) high require a 150mm (6 in) car setback.