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A plug door is a door designed to seal itself by taking advantage of pressure difference on its two sides and is typically used on aircraft with cabin pressurization. The higher pressure on one side forces the wedge-shaped door into its socket, making a good seal and preventing it being opened until the pressure is released.

Non-plug doors rely on the strength of the locking mechanism to keep the door shut whereas a plug door relies on the pressure differential to keep it shut.

The term "plug door" may also refer to a sliding bus door that is not actually held in place by pressure, but is mechanically wedged into place when closed.

Contents [hide] 1 Pressure-sealed plug doors 1.1 Aircraft 1.2 Spacecraft 2 Other plug doors 2.1 Buses 2.2 Passenger trains 2.3 Refrigerator cars

[edit]Pressure-sealed plug doors

The following doors are self-sealing, being held in place by pressure and are true plug doors.

[edit]Aircraft

The plug door is often seen on aircraft with pressurized cabins. Due to the air pressure within the aircraft cabin being higher than that of the surrounding atmosphere,