A door is a moving structure used to block off, and allow access to, an entrance to or within an enclosed space, such as a building or vehicle. Doors normally consist of a panel that swings on hinges on the edge, but there are also doors that slide or spin inside of a space. Similar exterior structures to doors are called gates.
Typically, doors have an interior side that faces the inside of a space and an exterior side that faces the outside of that space. In many cases the interior side of a door mostly matches its exterior side, but in some other cases there are sharp contrasts between the two sides, such as in the case of the vehicle door.
Sliding doors
It is often useful to have doors which slide along tracks, often for space or aesthetic considerations.
A bypass door is a door unit that has two or more sections. The doors can slide in either direction along one axis on parallel overhead tracks, sliding past each other. They are most commonly used in closets, in order to access one side of the closet at a time. The doors in a bypass unit will overlap slightly when viewed from the front, in order not to have a visible gap between them.
Doors which slide between two wall panels are called pocket doors.
Sliding glass doors are common in many houses, particularly as an entrance to the backyard. Such doors are also popular for use for the entrances to commercial structures, although they are not counted as fire exit doors. The door that moves is called the “active leaf”, while the door that remains fixed is called the “inactive leaf”.
Rotating doors
A revolving door has several wings or leaves, generally four, radiating from a central shaft, forming compartments that rotate about a vertical axis. A revolving door allows people to pass in both directions without colliding, and forms an airlock maintaining a seal between inside and out.
A pivot door, instead of hinges, is supported on a bearing some distance away from the edge, so that there is more or less of a gap on the pivot side as well as the opening side. In some cases the pivot is central, creating two equal openings.
High-speed door
A high-speed door is a very fast door some with opening speeds of up to 4 m/s, mainly used in the industrial sector where the speed of a door has an effect on production logistics, temperature and pressure control. High Speed Clean Room Doors are used in Pharmaceutical industries for the special curtain and stainless steel frames. They guarantee the tightness of all accesses. The powerful high-speed doors have a smooth surface structure and no protruding edges. Therefore, they can be easily cleaned and depositing of particles is largely excluded. High-speed doors are made to handle a high number of openings, generally more than 200000 a year. They need to be built with heavy duty parts and counterbalance systems for speed enhancement and emergency opening function. The door curtain was originally made of PVC, but was later also developed in aluminium and acrylic glass sections. High Speed refrigeration and cold room doors with excellent insulation values was also introduced with the Green and Energy saving requirements.