Door
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- This article is about the door as an architectural element. There is an article about The Doors who were a four-person musical band of the 1960s and early 1970s.
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A door is a structure in a wall that allows easy conversion between an opening and a closed wall. It is found in many houses and other buildings, as well as in vehicles, cupboards, cages, etc. See door furniture for a discussion of attachments to doors such as doorhandles and doorknobs.
The purpose of an opening is:
- for people, animals and objects to pass; some doors are for emergencies only (emergency exit)
- for air to pass (ventilation)
- for seeing and hearing what happens on the other side (however, some doors are partly or fully made of glass, thereby allowing visibility in any case)
The purpose of a closure is:
- for preventing air to pass: reducing air drafts and creating an enclosed space that can be heated or cooled more effectively. The use of doors is essential in colder climes where heating would be very difficult without them, and similarly in climates where air conditioning is used. Revolving doors are especially efficient for this purpose.
- for not seeing or hearing what happens on the other side: privacy, avoiding noise
- for preventing falling out (in vehicles)
- regulation of access. Combined with various types of locks, doors become important safety measures.
- for esthetics (e.g. cupboard doors preventing the sight of the contents).
- for helping prevent fire to spread.
Doors can also have ritual purposes (see Black Rod for an example of the opening and closing of doors having a symbolic meaning).
A door is usually fastened in a doorway, that is a frame constructed around the edges of a hole in a wall or other containing structure. The two vertical members of the frame are called jambs.
Types of doors
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Many kinds of doors have specific names, depending on their purpose. The most common variety of door consists of a single rigid panel that fills the doorway, hinged along one side so that it can fold away from the doorway in one direction but not in the other. Many variations on this basic design are possible, such as "double" doors that have two adjacent independent panels hinged on each side of the doorway.
A trapdoor is a door that is oriented horizontally in a floor or ceiling, often accessed via a ladder.
A stable door is divided in half horizontally. The top half can be opened to allow the horse to be fed, while the bottom half can be closed to keep the animal inside.
A swing door has special hinges that allow it to open either outwards or inwards, and is usually sprung to keep it closed. Saloon doors are a pair of lightweight swing doors often found in public bars.
An up-and-over door is often used in garages. Instead of hinges it has a mechanism, often counterbalanced or sprung, that allows it to be lifted so that it rests horizontally above the opening.
A barn door is a very large sliding door that covers the entire side of a barn.
A French door is a door that has multiple lights, the full length of the door. Traditional French doors are assembled from individual small pieces of glass and mullions. French doors made of double-pane glass (on exterior doors for insulation reasons) may have the decorative grill embedded between the panes. The decorative grill may also be superimposed on top of single pane of glass in the door.
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A sliding glass door is a glass door that slides to open. It goes in an opening at least twice the width of the sliding door and is composed of two panels of glass. One panel is fixed and the other slides. Sliding glass doors are most commonly used for large views of backyards
A garden door is any door that opens to a garden or backyard. It is often used specifically for double French doors in place of a sliding glass door. In such a configuration, it has the advantage of a very large opening for moving large objects in and out.
A pet door is an opening in a door to allow pets to enter and exit without the main door being opened. It may be simply covered by a rubber flap or it may be an actual door hinged on the top that the pet can push through. Pet doors may be mounted in a sliding glass door as a new (permanent or temporary) panel. Pet doors may be unidirectional, only allowing pets to exit. Pet doors may be electronic, only allowing pets with a special electronic tag to enter.
A revolving door is a type of door that typically consists of a structure with at least four panels that meet in the center that has an axle. A person using the door pushes a panel in the desired direction in or out of the building, causing the door to rotate in the structure until the person has access out. This door design is used primarily to maintain an air seal from the outside, thus minimizing leaking of climate controlled air from the building and the resulting expense of compensating for the loss. This type of door is also often seen as a mark of prestige and glamour for a building and it not unusual for neighbouring buildings installing their own revolving doors when a rival building gets one.
Automatic doors open with little effort to its user. The user of a regular door would normally have to push of pull it open with their hands, but an automatic door just requires the activation of some sort of sensor. Sensors for automatic doors are generally pressure sensors or light sensors. Heron of Alexandria created the first automatic door.
Door construction
Traditional doors are constructed from vertical planks of wood held together by horizontal beams called ledges (hence ledged door). Often they are strengthened by diagonal beams, running upwards from the hinges, called braces (hence braced and ledged and braced doors).
Recently (c. 20th century) hollow doors have been used, consisting of a thin wooden frame covered by hardboard or plywood. Many houses now have external doors that are aluminium-framed with a polyvinyl chloride exterior. Steel doors are also very common for exterior doors.
Doors are constructed to be symmetric. Which way it opens is determined at installation when the hole for the door knob and lock and bolt are drilled on-site to match existing lock locations. For hollow doors, the area where the door knob goes is not hollow but solid and reinforced.
External links
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