A door is a panel or

DOOR -- ITS TRUE

A door is a panel or barrier, usually hinged, sliding, or electronic, that is used to cover an opening in a wall or partition going into a building or space. A door can be opened to give access and closed more or less securely. The term door is also applied to the opening itself, more properly known as the doorway.

Doors are nearly universal in buildings of all kinds, allowing passage between the inside and outside, and between internal rooms. When open, they admit ventilation and light.

The purpose of a door closure is primarily to give occupants of a space privacy and security by regulating access. For this purpose doors are equipped with a variety of fittings ranging from simple latches to locks.

The door is used to control the physical atmosphere within a space by enclosing it, excluding air drafts, so that interiors may be more effectively heated or cooled. Doors are significant in preventing the spread of fire.

Doors also have an aesthetic role in creating an impression of what lies beyond. They are also used to screen areas of a building for aesthetic purposes, keeping formal and utility areas separate. They act as a barrier to noise.

Doors are often symbolically endowed with ritual purposes, and the guarding or receiving of the keys to a door, or being granted access to a door can have special significance. [1] Similarly, doors and doorways frequently appear in metaphorical or allegorical situations, literature and the arts, often as a portent of change.

When framed in wood for snug fitting of a door, the doorway consists of two vertical jambs on either side, a lintel or head jamb at the top, and perhaps a threshold at the bottom. When a door has more than one movable panel, one of the panels may be called a leaf.

See door furniture for a discussion of attachments to doors such as doorhandles and doorknobs. Doors are also found in cupboards and other furniture, cages, and vehicles.

A door may slide along tracks, pivot on hinges or fold.

The door may also slide between two wall panels (pocket door).

In the case of rotation, the axis is usually vertical, but e.g. for garage doors often horizontal, above the door opening. Sometimes the axis of rotation is, with a special construction, not in the plane of the door, on the other side than that in which the door opens, to reduce the space required on the side to which the door opens. This is sometimes the case in a train, for the door to the toilet, opening inward.

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. Stable doors are also known as dutch doors.

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. Saloon doors, also known as cafe doors, often use double action hinges, which will return the door to the center, regardless of which direction it is opened, due to the double action springs in the doors.

A blind door is a door with no visible trim or operable components. It is designed to blend with the adjacent wall in all finishes, and visually to be a part of the wall, a disguised door.

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. Also known as an overhead door.

A barn door is a door on a barn. It is often/always found on barns, and because of a barn’s immense size (often) doors are subsequently big for utility.

A French door, also called a French window, is a door that has multiple windows ("lights") set into it, the full length of the door. Traditional French doors are assembled from individual small pieces of glass and mullions. These doors are also known as true divided lite[sic] French doors. French doors made of double-pane glass (on exterior doors for insulation reasons) may have a decorative grille embedded between the panes, or may also be true divided lite French doors. The decorative grille may also be superimposed on top of single pane of glass in the door.

A louver door has fixed or movable wooden fins (often called slats or louvers) which permit open ventilation whilst preserving privacy and preventing the passage of light to the interior. Being relatively weak structures, they are most commonly used for wardrobes and drying rooms, where security is of less importance than good ventilation, although a very similar structure is commonly used to form window shutters.

A flush door is a completely smooth door, having plywood or MDF fixed over a light timber frame, the hollow parts of which are often filled with a cardboard core material. Flush doors are most commonly employed in the interior of a dwelling, although slightly more substantial versions are occasionally used as exterior doors, especially within hotels and other buildings containing many independent dwellings.

A moulded door has the same structure as that of flush door. The only difference is that the surface material is a moulded skin made of HDF / MDF. It is commonly used as interior doors.

A ledge and brace door is a door made from multiple vertical planks fixed together by two horizontal planks (the ledges) and kept square by a diagonal plank (the brace).

Mechanism of the sliding door of an elevator

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 bifold door is door unit that has 2 to 4 sections, folding in pairs. The doors can open from either side for one pair, or fold off both sides for two pairs. Wood is the most common material, and doors may also be metal or glass. Bifolds are most commonly made for closets, but may also be used as units between rooms.

A bypass door is a door unit that has 2 or more sections. The doors can slide from each direction on an overhead track, 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, in order not to have a gap between them.

A pocket door is a door that slides on rails, rather than swinging on hinges, and, when opened, slides into an open cavity within a wall.

A sliding glass door, sometimes called an Arcadia door, is a door made of glass that slides open and sometimes has a screen. 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.

A false door is a wall decoration that looks like a door. In ancient Egyptian architecture, this was a common element in a tomb, the false door representing a gate to the afterlife. They can also be found in the funerary architecture of the desert tribes (e.g., Libyan Ghirza). It may have influenced the mihrab in a mosque.

A revolving door typically consists of three or four doors (wings/leaves) that hang on a center shaft and rotate one way about a vertical axis. Between the point of access and the point of exit the user walks through an airlock. The door may be motorized, or manually people use pushbars. People can walk out and into the building at the same time. Revolving doors are a good air seal from the outside. Also minimize A/C and Heating Costs climate control from the building. 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 to install their own revolving doors when a rival building gets one.

A Butterfly Door is so-called because of its two "wings". It consists of a double-wide panel with its rotation axle in the centre, effectively creating two separate openings when the door is opened. Butterfly doors are made to rotate open in one direction (usually counterclockwise), and rotate closed in the opposite direction. The door is not equipped with handles, so it is a "push" door. This is for safety, because if it could open in both directions, someone approaching the door might be caught off guard by someone else opening the other side, thus impacting the first person. Such doors are popular in public transit stations, as it has a large capacity, and when the door is opened, traffic passing in both directions keeps the door open. They are particularily popular in underground subway stations, because they are heavy, and when air currents are created by the movement of trains, the force will be applied to both wings of the door, thus equalizing the force on either side, keeping the door shut.

Automatic doors are powered open and closed, a door fitted with a spring to close it is not an automatic door. There are three methods by which an automatic door is activated.

Inward opening doors are doors that can only be opened or forced open from outside a building. Such doors pose a substantial fire risk to occupants of occupied buildings when they are locked. As such doors can only be forced open from the outside, those within buildings are prevented from escape, unless people outside the building can force the doors open and off their hinges as there is no way to lever a door open from inside.

1 - A sensor detects traffic is approaching. Sensors for automatic doors are generally:
A pressure sensor - a floor mat which reacts to the pressure of someone standing on it.
An infrared curtain or beam which shines invisible light onto sensors; if someone or something blocks the beam the door can open.
A motion sensor which uses low-power microwave radar.
An electronic sensor (e.g. based on infrared or radio waves) can be triggered by something that someone carries, or is installed inside a vehicle. These are popular for garage doors.

2 - A switch is operated manually, perhaps after security checks. This can be a push button switch or a swipe card.

3 - The user pushes, or pulls the door, once the door detects the movement it completes the open and close cycle. These are also known as power-assisted doors.

Leaf Diagrams of the selfbolting door concept

In addition to activate sensors automatic doors are generally fitted with safety sensors. These are usually an infrared curtain or beam, but can be a pressure mat fitted on the swing side of the door. The purpose of the safety sensor is to prevent the door opening or slow its speed if an object is detected in its path whilst opening and to prevent the door closing or reactivate it if an object is detected in its path whilst closing.

Heron of Alexandria created the earliest known automatic door in the 1st century AD. Later in the 13th century, al-Jazari created more elaborate automatic gates.[2]

Blast-proof doors, nuclear-blast proof doors, etc.

A tambour door is made of narrow horizontal slats and rolls up and down along vertical tracks and is typically found in entertainment centres and cabinets.

A selfbolting door is a door that has special hinges that allows a door leaf to slide into the place of the bolt after complete closing.

Door components

A diagram illustrating the components of a panel door

Doorway
Lintel - A horizontal beam above a door that supports the wall above it. (Also known as a header)
Jambs - The vertical posts that form the sides of a door frame, where the hinges are mounted, and with which the bolt interacts.
Sill - A horizontal beam below the door that supports the frame
Doorstop - a thin slat built inside the frame to prevent a door from swinging through when closed, which might break the hinges.
Architrave - The decorative molding that outlines a door frame. (called an Archivolt if the door is arched). Called door casing or brickmold in North America.
Related hardware
Hinge- A component that attaches one edge of a door to the frame, while allowing the other edge to swing from it. It usually consists of a pair of plates, each with a set of open cylindrical rings (the knuckles) attached to them. The knuckles of the two plates are offset from each other and mesh together. A hinge pin is then placed through the two sets of knuckles and usually fixed, to combine the plates and make the hinge a single unit. One door usually has about three hinges, but it can vary.
Door closer - A hydraulic device installed at the top of the door and employed to slow the door’s closure behind someone.
Handles:
Doorknob - A knob or lever on an axle that is rotated to release the bolt.
Door handle - A fixed handle, usually accompanied with a latch to release the bolt, on some doors (such as car doors) the latch is incorporated into a hinged handle that releases when pulled on. A handleset is composed of the exterior handle (including escutcheon), an independent deadbolt, and the interior package (knob or lever)
Crash bar - A spring-loaded bar that is mounted horizontally on the side of the door that opens outward. When pushed upon, the bolt is released. This device is mandatory in most fire exits. Many of these doors are one-way, and cannot be opened from the outside. To use this device on a two-way door, another type of handle must be mounted on the opposite side. (Also known as a "panic bar" or "cross-bar", see below for an older use of this term which has a different function.)
Fasteners:
Crossbar, sometimes called a bolt (see below for modern use of this term) - A historically common, simple fastener consisting simply of a plank or beam mounted to one side of a door by a set of cleats. The board can be slid past the frame to block the door. Alternatively, the bar can be a separate piece that is placed into open cleats or hooks, extending across the frame on both sides. The effect of this device is essentially the opposite of the crash bar (see above), in that its operation is to permit the door to be opened inward rather than outward. On a set of double doors, the same principle works, but needn’t extend past the frame. The bar simply extends into another set of cleats on the other door such as to interfere with the door opening.
Latch - A device that allows one to fasten a door, but doesn’t necessarily require an external handle

A typical peephole in a door, allowing the person to see who is outside the door without opening it.
Lock - A device that prevents access by those without a key or combination.
A typical peephole in a door, allowing the person to see who is outside the door without opening it.
Bolt - A (nearly always) metal shaft usually internal to the door, attached by cleats or a specific form of bracket, that slides into the jamb to fasten a door.
Latchbolt - A bolt that has an angled surface which acts as a ramp to push the bolt in while the door is being closed. By the use of a latchbolt, a door can be closed without having to operate the handle.
Deadbolt - Deadbolts usually extend deeper into the frame and are not automatically retractable the way latchbolts are. They are typically manipulated with a lock on the outside and either a lock or a latch on the inside. Deadbolts are generally used for security purposes on external doors in case somebody tries to kick the door in or use a tool such as a crowbar or a hammer and screwdriver etc.
Strike - A plate with a hole in the middle made to receive a bolt. If the strike is for a latchbolt, it typically also includes a small ramped area to help the bolt move inward while the door is being closed. (Also known as a "strikeplate")

Door construction

Parts of a panel and or glazed door

joint between midrail, lockrail and a gunstock stile

A frame and filled door

Panel doors (doors built with frame and panel, construction, also called stile and rail doors):
Stiles - Vertical boards that run the full height of a door and compose its right and left edges. The hinges are mounted to the fixed side (known as the "hanging stile"), and the handle, lock, bolt, and/or latch are mounted on the swinging side (known as the "latch stile").
Rails - Horizontal boards at the top, bottom, and optionally in the middle of a door that join the two stiles and split the door into two or more rows of panels. The "top rail" and "bottom rail" are named for their positions. The bottom rail is also known as "kick rail". A middle rail at the height of the bolt is known as the "lock rail", other middle rails are commonly known as "cross rails".
Mullions - Smaller optional vertical boards that run between two rails, and split the door into two or more columns of panels, the term is used sometimes for verticals in doors, but more often (UK and Australia) it refers to verticals in windows.
Muntin - Optional vertical members that divide the door into smaller panels.
Panels - Large, wider boards used to fill the space between the stiles, rails, and mullions. The panels typically fit into grooves in the other pieces, and help to keep the door rigid. Panels may be flat, or in raised panel designs.
Lights,(UK); Lites,(US) - Pieces of glass used in place of a panel, essentially giving the door a window.

Plank and batten doors, (an older design consisting primarily of vertical slats):
Planks - Vertical boards that extend the full height of the door, and are placed side by side filling the door’s width.
Battens - Smaller slats that extend horizontally across the door which the planks are affixed to. The battens hold the planks together. Sometimes a long diagonal slat or two are also implemented to prevent the door from skewing. On some doors, especially antique ones, the battens are replaced with iron bars that are often built into the hinges as extensions of the door-side plates.

Ledged and braced doors Consists of vertical tongue and grooved boards held together with battens and diagonal braces.

Frame and filled door Consists of a solid timber frame, filled on one face, face with Tongue and Grooved boards. Quite often used externally with the boards on the weather face.

Flush doors (many modern doors, including most interior doors):
Stiles and rails - As above, but usually smaller. They form the outside edges of the door.
Core material: Material within the door used simply to fill space, provide rigidity and reduce druminess.
Hollow-core - Often consists of a lattice or honeycomb made of corrugated cardboard, or thin wooden slats. Can also be built with staggered wooden blocks. Hollow-core flush doors are commonly used as interior doors.
Lock block - A solid block of wood mounted within a hollow-core flush door near the bolt to provide a solid and stable location for mounting the door’s hardware.
Stave-core - Consists of wooden slats stacked upon one another in a manner similar to a plank & batten door (though the slats are usually thinner) or the wooden-block hollow-core (except that the space is entirely filled).
Solid-core - Can consist of low-density particle board or foam used to completely fill the space within the door. Solid-core flush doors (especially foam-core ones) are commonly used as exterior doors because they provide more insulation and strength.
Skin - The front and back faces of the door are then covered with wood veneer, thin plywood, sheet metal, fiberglass, or vinyl. The wooden materials are usually layered with the grain alternating direction between layers to prevent warping. Fiberglass and metal-faced doors are sometimes given a layer of cellulose so that they may be stained to look like real wood.

Moulded doors
Stiles and rails - As above, but usually smaller. They form the outside edges of the door.
Core material: Material within the door used simply to fill space, provide rigidity and reduce druminess.
Hollow-core - Often consists of a lattice or honeycomb made of corrugated cardboard, or thin wooden slats. Can also be built with staggered wooden blocks. Hollow-core flush doors are commonly used as interior doors.
Lock block - A solid block of wood mounted within a hollow-core flush door near the bolt to provide a solid and stable location for mounting the door’s hardware.
Stave-core - Consists of wooden slats stacked upon one another in a manner similar to a plank & batten door (though the slats are usually thinner) or the wooden-block hollow-core (except that the space is entirely filled).
Solid-core - Can consist of low-density particle board or foam used to completely fill the space within the door. Solid-core flush doors (especially foam-core ones) are commonly used as exterior doors because they provide more insulation and strength.
Skin - The front and back faces of the door are covered with HDF / MDF skins.

Door swing directions diagram.

Door swings

Door swings, or handing, are always determined from the secure side of the door (ie. the side you use the key on, outside to inside, or public to private).
Left hand (LH): If the hinges are on the left and the door opens in, it’s a left hand door. You push the door with your left hand.
Right hand (RH): If the hinges are on the right and the door opens in, it’s a right hand door. You push the door with your right hand.
Left hand reverse (LHR): If the hinges are on the left and the door pulls away from you, it’s a left hand reverse door. You pull the door with your left hand.
Right hand reverse (RHR): If the hinges are on the right and the door pulls away from you, it’s a right hand reverse door. You pull the door with your right hand.

History

An old door, Kashan, Iran

The earliest records are those represented in the paintings of the Egyptian tombs, in which they are shown as single or double doors, each in a single piece of wood. In Egypt, where the climate is intensely dry, there would be no fear of their warping, but in other countries it would be necessary to frame them, which according to Vitruvius (iv. 6.) was done with stiles (sea/si) and rails (see: Frame and panel): the spaces enclosed being filled with panels (tympana) let into grooves made in the stiles and rails. The stiles were the vertical boards, one of which, tenoned or hinged, is known as the hanging stile, the other as the middle or meeting stile. The horizontal cross pieces are the top rail, bottom rail, and middle or intermediate rails. The most ancient doors were in timber, those made for King Solomon’s temple being in olive wood (I Kings vi. 31-35), which were carved and overlaid with gold. The doors dwelt upon in Homer would appear to have been cased in silver or brass. Besides Olive wood, elm, cedar, oak and cypress were used.

Stone door, Hampi, India

All ancient doors were hung by pivots at the top and bottom of the hanging stile which worked in sockets in the lintel and sill, the latter being always in some hard stone such as basalt or granite. Those found at Nippur by Dr. Hilprecht, dating from 2000 B.C. were in dolerite. The tenons of the gates at Balawat were sheathed with bronze (now in the British Museum). These doors or gates were hung in two leaves, each about 8 ft.4 in. wide and 27 ft. high; they were encased with bronze bands or strips, 10 in. high, covered with repouss decoration of figures, etc. The wood doors would seem to have been about 3 in. thick, but the hanging stile was over 14 inches diameter. Other sheathings of various sizes in bronze have been found, which proves this to have been the universal method adopted to protect the wood pivots. In the Hauran in Syria, where timber is scarce the doors were made in stone, and one measuring 5 ft. 4 in. by 2 ft. 7 in. is in the British Museum; the band on the meeting stile shows that it was one of the leaves of a double door. At Kuffeir near Bostra in Syria, Burckhardt found stone doors, 9 to 10 ft. high, being the entrance doors of the town. In Etruria many stone doors are referred to by Dennis.

Roman folding doors at Pompeii (1st century AD).

The ancient Greek and Roman doors were either single doors, double doors, sliding doors or folding doors, in the last case the leaves were hinged and folded back. In Eumachia, is a painting of a door with three leaves. In the tomb of Theron at Agrigentum there is a single four-panel door carved in stone. In the Blundell collection is a bas-relief of a temple with double doors, each leaf with five panels. Among existing examples, the bronze doors in the church of SS. Cosmas and Damiano, in Rome, are important examples of Roman metal work of the best period; they are in two leaves, each with two panels, and are framed in bronze. Those of the Pantheon are similar in design, with narrow horizontal panels in addition, at the top, bottom and middle. Two other bronze doors of the Roman period are in the Lateran Basilica.

The doors of the church of the Nativity at Bethlehem (6th century) are covered with plates of bronze, cut out in patterns: those of Hagia Sophia at Constantinople, of the 8th and 9th century, are wrought in bronze, and the west doors of the cathedral of Aix-la-Chapelle (9th century), of similar manufacture, were probably brought from Constantinople, as also some of those in St. Marks, Venice.

Ornate door. Roman wall painting in the Villa Boscoreale, Italy (1st century AD).

Of the 11th and 12th centuries there are numerous examples of bronze doors, the earliest being one at Hildesheim, Germany (1015). Of others in South Italy and Sicily, the following are the finest: in Sant Andrea, Amalfi (1060); Salerno (1099); Canosa (1111); Troia, two doors (1119 and 1124); Ravello (1179), by Barisano of Trani, who also made doors for Trani cathedral; and in Monreale and Pisa cathedrals, by Bonano of Pisa. In all these cases the hanging stile had pivots at the top and bottom. The exact period when the hinge was substituted is not quite known, but the change apparently brought about another method of strengthening and decorating doors, viz, with wrought-iron bands of infinite varieties of design. As a rule three bands from which the ornamental work springs constitute the hinges, which have rings outside the hanging stiles fitting on to vertical tenons run into the masonry or wooden frame. There is an early example of the 12th century in Lincoln; in France the metal work of the doors of Notre Dame at Paris is perhaps the most beautiful in execution, but examples are endless throughout France and England.

Returning to Italy, the most celebrated doors are those of the Battistero di San Giovanni (Florence), which together with the door frames are all in bronze, the borders of the latter being perhaps the most remarkable: the modeling of the figures, birds and foliage of the south doorway, by Andrea Pisano (1330), and of the east doorway by Ghiberti (1425-1452), are of great beauty; in the north door (1402-1424) Ghiberti adopted the same scheme of design for the paneling and figure subjects in them as Andrea Pisano, but in the east door the rectangular panels are all filled, with bas-reliefs, in which Scripture subjects are illustrated with innumerable figures, these being probably the gates of Paradise of which Michelangelo speaks.

An old door, Isfahan, Iran

The doors of the mosques in Cairo were of two kinds; those which, externally, were cased with sheets of bronze or iron, cut out in decorative patterns, and incised or inlaid, with bosses in relief; and those in wood, which were framed with interlaced designs of the square and diamond, this latter description of work being Coptic in its origin. The doors of the palace at Palermo, which were made by Saracenic workmen for the Normans, are fine examples and in good preservation. A somewhat similar decorative class of door to these latter is found in Verona, where the edges of the stiles and rails are beveled and notched.

In the Renaissance period the Italian doors are quite simple, their architects trusting more to the doorways for effect; but in France and Germany the contrary is the case, the doors being elaborately carved, especially in the Louis XIV and Louis XV periods, and sometimes with architectural features such as columns and entablatures with pediment and niches, the doorway being in plain masonry. While in Italy the tendency was to give scale by increasing the number of panels, in France the contrary seems to have been the rule; and one of the great doors at Fontainebleau, which is in two leaves, is entirely carried out as if consisting of one great panel only.

The earliest Renaissance doors in France are those of the cathedral of St. Sauveur at Aix (1503). In the lower panels there are figures 3 ft. high in Gothic niches, and in the upper panels a double range of niches with figures about 2 ft. high with canopies over them, all carved in cedar. The south door of Beauvais Cathedral is in some respects the finest in France; the upper panels are carved in high relief with figure subjects and canopies over them. The doors of the church at Gisors (1575) are carved with figures in niches subdivided by classic pilasters superimposed. In St. Maclou at Rouen are three magnificently carved doors; those by Jean Goujon have figures in niches on each side, and others in a group of great beauty in the center. The other doors, probably about forty to fifty years later, are enriched with bas-reliefs, landscapes, figures and elaborate interlaced borders.

In England in the 17th century the door panels were raised with bolection or projecting moldings, sometimes richly carved, round them; in the 18th century the moldings worked on the stiles and rails were carved with the egg and tongue ornament.

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