It is often useful to have a door that slides along the rails, often for space or aesthetic considerations. Bypass door is a door unit that has two or more parts. Doors can slide in both directions along one axis parallel to the track head, sliding past each other. They are most often used in closets, to access one side of the cabinet at a time. The doors on the cutting unit will overlap slightly when viewed from the front, so as not to have a visible gap between them. Doors that slid in between two wall panels called pocket doors. Sliding glass doors are common in many homes, especially as the entrance to the backyard. The door is also popular to be used for entrance to a commercial structure. A revolving door typically has four wings / leaves that hang on the center shaft and rotate one way about a vertical axis.
This door may be motorized, or pushed manually using pushbars. People can walk into and out of the building at the same time. Between access point and exit point the user goes through an airlock. Therefore, the revolving door makes a good seal from the outside and helps to reduce A / C and heating costs of building climate control. This type of door is also often seen as a sign of prestige and glamor to build and is not uncommon for neighboring buildings to install their own revolving doors when a rival building to get one.
Butterfly doors are called for two “wings”. It consists of a double-wide panel with the axis of rotation in the middle, effectively creating two separate openings when the doors opened.
Butterfly doors are made to rotate open in one direction (typically opposite), and rotate closed in the opposite direction. The door is not equipped with a handle, so it is a “push” door. This is for safety, because if it could be open in both directions, someone approaching the door might be caught off-guard by someone else opening the other side, so the impact on people first.
The door is popular in public transit stations, because it has a large capacity, and when the door opened, traffic passing in both directions remain open doors. They are very popular in the subway station underground, because they are heavy, and when the air currents created by the movement of trains, the force will be applied on both wings of the door, thus equating the force on both sides, keeping the door shut.