Door
A door is a hinged or otherwise movable barrier that allows ingress into and egress from an enclosure. The created opening in the wall is a doorway or portal. A door's essential and primary purpose is to provide security by controlling access to the doorway. Conventionally, it is a panel that fits into the doorway of a building, room, or vehicle. Doors are generally made of a material suited to the door's task. They are commonly attached by hinges, but can move by other means, such as slides or counterbalancing.
The door may be able to move in various ways to allow or prevent ingress or egress. In most cases, a door's interior matches its exterior side. But in other cases the two sides are radically different.
Many doors incorporate locking mechanisms to ensure that only some people can open them. Doors may have devices such as knockers or doorbells by which people outside announce their presence. Apart from providing access into and out of a space, doors may have the secondary functions of ensuring privacy by preventing unwanted attention from outsiders, of separating areas with different functions, of allowing light to pass into and out of a space, of controlling ventilation or air drafts so that interiors may be more effectively heated or cooled, of dampening noise, and of blocking the spread of fire.
Doors can have aesthetic, symbolic, or ritualistic purposes. Receiving the key to a door can signify a change in status from outsider to insider. Doors and doorways frequently appear in literature and the arts with metaphorical or allegorical import as a portent of change.
History
The earliest recorded doors appear in the paintings of Egyptian tombs, which show them as single or double doors, each of a single piece of wood. People may have believed these were doors to the afterlife, and some include designs of the afterlife. In Egypt, where the climate is intensely dry, doors were not framed against warping, but in other countries required framed doors—which, according to Vitruvius was done with stiles and rails , the enclosed panels filled with tympana set in grooves 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 made of timber, such as those referred to in the Biblical depiction of King Solomon's temple being in olive wood, which were carved and overlaid with gold. The doors that Homer mentions appear to have been cased in silver or brass. Besides olive wood, elm, cedar, oak and cypress were used. Two doors over 5,000 years old have been found by archaeologists near Zürich, Switzerland.
Ancient doors were hung by pintles at the top and bottom of the hanging stile, which worked in sockets in the lintel and sill, the latter in some hard stone such as basalt or granite. Those Hilprecht found at Nippur, dating from 2000 BC, were in dolerite. The tenons of the gates at Balawat were sheathed with bronze. These doors or gates were hung in two leaves, each about wide and high; they were encased with bronze bands or strips, high, covered with repoussé decoration of figures. The wood doors would seem to have been about thick, but the hanging stile was over diameter. Other sheathings of various sizes in bronze show this was a universal method adopted to protect the wood pivots. In the Hauran in Syria, where timber is scarce, the doors were made of stone, and one measuring 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, high, being the entrance doors of the town. In Etruria, many stone doors are referred to by Dennis.
File:Plaster cast of folding doors, Pompeii.jpg|thumb|left|upright|Roman folding doors at Pompeii, from the first century AD, similar with Neoclassical doors from the 19th century
Ancient Greek and Roman doors were either single doors, double doors, triple doors, sliding doors, or folding doors. In the last case, the leaves were hinged and folded back. 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 Greek scholar Heron of Alexandria created the earliest known automatic door in the first century AD during the era of Roman Egypt. The first foot-sensor-activated automatic door was made in China during the reign of Emperor Yang of Sui, who had one installed for his royal library. Gates powered by water featured in illustrations of the automatons of the Arab inventor Al-Jazari.
Copper and its alloys were integral in medieval architecture. The doors of the church of the Nativity at Bethlehem are covered with plates of bronze, cut out in patterns. Those of Hagia Sophia at Constantinople, of the eighth and ninth century, are wrought in bronze, and the west doors of the cathedral of Aix-la-Chapelle, of similar manufacture, were probably brought from Constantinople, as also some of those in St. Marks, Venice. The bronze doors on the Aachen Cathedral in Germany date back to about 800 AD. Bronze baptistery doors at the Cathedral of Florence were completed in 1423 by Ghiberti. .
File:Tür, Villa Boscoreale.jpg|left|thumb|upright|Roman wall painting of an ornate door, in the Villa Boscoreale, from the first century AD
Of the 11th and 12th centuries there are numerous examples of bronze doors, the earliest being one at Hildesheim, Germany. The Hildesheim design affected the concept of Gniezno door in Poland. Of others in South Italy and Sicily, the following are the finest: in Sant'Andrea, Amalfi ; Salerno ; Canosa di Puglia ; Troia, two doors ; Ravello, 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 builder moved to the hinge is unknown, but the change apparently brought about another method of strengthening and decorating doors—wrought-iron bands of various designs. As a rule, three bands with ornamental work constitute the hinges, with rings outside the hanging stiles that fit on vertical tenons set into the masonry or wooden frame. There is an early example of the 12th century in Lincoln. In France, the metalwork of the doors of Notre Dame at Paris is a beautiful example, but many others exist throughout France and England.
In Italy, celebrated doors include those of the Battistero di San Giovanni, which are all in bronze, including the door frames. The modeling of the figures, birds, and foliage of the south doorway, by Andrea Pisano, and of the east doorway by Ghiberti, are of great beauty. In the north door, Ghiberti adopted the same scheme of design for the paneling and figure subjects as Andrea Pisano, but in the east door, the rectangular panels are all filled, with bas-reliefs that illustrate Scripture subjects and innumerable figures. These may the gates of Paradise of which Michelangelo speaks.
Doors of the mosques in Cairo were of two kinds: those externally cased with sheets of bronze or iron, cut in decorative patterns, and incised or inlaid, with bosses in relief; and those of wood-framed with interlaced square and diamond designs. The latter design is Coptic in origin. The doors of the palace at Palermo, which were made by Saracenic workmen for the Normans, are fine examples in good preservation. A somewhat similar decorative class of door is found in Verona, where the edges of the stiles and rails are beveled and notched.
File:Дом компании Зингер, Россия, Санкт-Петербург.JPG|thumb|upright|Glass door decorated with Art Nouveau elements, from the Singer House
In the Renaissance period, 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. In the lower panels, there are figures. high in Gothic niches, and in the upper panels a double range of niches with figures about. 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 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.
NASA's Vehicle Assembly Building at the Kennedy Space Center contains the four largest doors. The Vehicle Assembly Building was originally built for the assembly of the Apollo missions' Saturn vehicles and was then used to support Space Shuttle operations. Each of the four doors are high.
The oldest door in England can be found in Westminster Abbey and dates from 1050. In England in the 17th century, the door panels were raised with bolection or projecting moldings, sometimes richly carved, around them. In the 18th century, the moldings worked on the stiles and rails were carved with the egg-and-dart ornament.