Revolving doors consist of 3 or 4 panels fanning out from a central shaft rotating within an enclosed cylinder. The door’s movement is powered either by someone pushing the door panels or a motor which rotates the door automatically.
The doors create two clear channels for entering and exiting a building. This eases congestion and avoids collision. No more letting people through before going in first yourself.
Chivalrous acts aside, the door also doubles up as an airlock, preventing air from escaping the building. This keeps heating and cooling costs to a minimum.
The entrance to RDD in Malmesbury uses revolving doors as a security device. It restricts entry to a single person at a time. This makes it difficult for unauthorized persons to tailgate as they could through a regular door.