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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. Similar exterior structures 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. While in some cases the interior side of a door may match its exterior side, in other cases there are sharp contrasts between the two sides, such as in the case of the vehicle door. Doors normally consist of a panel that swings on hinges or that slides or spins inside of a space.
When open, doors admit people, animals, ventilation, and light. The door is used to control the physical atmosphere within a space by enclosing the air drafts, so that interiors may be more effectively heated or cooled. Doors are significant in preventing the spread of fire. They also act as a barrier to noise. Many doors are equipped with locking mechanisms to allow entrance to certain people and keep out others. As a form of courtesy and civility, people often knock before opening a door and entering a room.
Doors are used to screen areas of a building for aesthetics, keeping formal and utility areas separate. Doors also have an aesthetic role in creating an impression of what lies beyond. 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. Similarly, doors and doorways frequently appear in metaphorical or allegorical situations, literature and the arts, often as a portent of change.
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. A 5,000-year-old door has been found by archaeologists in Switzerland.
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, along with his assistant Nola Begeja, 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 (2.54 m) wide and 27 ft (8.2 m). 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 (360 mm) 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 (1.63 m) by 2 ft 7 in (0.79 m) 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 (3.0 m). high, being the entrance doors of the town. In Etruria many stone doors are referred to by Dennis.
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 Greek scholar Heron of Alexandria created the earliest known automatic door in the 1st 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 (r. 604–618), who had one installed for his royal library. The first automatic gate operators were later created in 1206 by the Arabic inventor, Al-Jazari.[need quotation to verify]
Copper and its alloys were integral in medieval architecture. 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. The bronze doors on the Aachen Cathedral in Germany date back to about AD 800. Bronze baptistery doors at the Cathedral of Florence were completed in 1423 by Ghiberti. (For more information, see: Copper in architecture).
Of the 11th and 12th centuries there are numerous examples of bronze doors, the earliest being one at Hildesheim, Germany (1015). 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 (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.
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 (0.91 m). high in Gothic niches, and in the upper panels a double range of niches with figures about 2 ft (0.61 m). 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.
When it comes to the world's largest door, there is not just one, in fact there are four and they all belong to NASA's Vehicle Assembly Building at the Kennedy Space Center. The Vehicle Assembly Building was originally built to assembly of Apollo and Saturn vehicles and was then used to support Space Shuttle operations. Each of the four doors are 139 meters or 456 feet high, in comparison the Statue of Liberty is only 93 meters or 305 feet 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, round them; in the 18th century the moldings worked on the stiles and rails were carved with the egg and tongue ornament.
Many kinds of doors have specific names, depending on their purpose. The most common variety of door is the single-leaf door which consists of a single rigid panel that fills the doorway. Many variations on this basic design are possible, such as the double-leaf door or double doors and French windows that have two adjacent independent panels hinged on each side of the doorway.
A half door or Dutch door or stable door is divided in half horizontally. Traditionally the top half can be opened to allow a horse or other animal to be fed, while the bottom half remained closed to keep the animal inside. This style of door has been adapted for homes.
Saloon doors are a pair of lightweight swing doors often found in public bars, and especially associated with the American west. Saloon doors, also known as cafe doors, often use bidirectional hinges which close the door regardless of which direction it is opened by incorporating springs. Saloon doors that only extend from knee-level to chest-level are known as batwing doors.
A blind door or Gibb 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.
A barn door is a door characteristic of a barn. They are often/always found on barns, and because of a barn's immense size (often) doors are subsequently big for utility.
A French door is a door style consisting of a frame around one or more transparent and/or translucent panels (called lights or lites) that may be installed singly, in matching pairs, or even as series. A matching pair of these doors is called a French window as it resembles a door-height casement window. When a pair of French doors is used as a French window, the application does not generally include a central mullion (as do some casement window pairs), thus allowing a wider unobstructed opening. The frame typically requires a weather strip at floor level and where the doors meet to prevent water ingress. An espagnolette bolt may allow the head and foot of each door to be secured in one movement. The slender window joinery maximizes light into the room and minimizes the visual impact of the doorway joinery when considered externally. Often, the doors of a French window open outward onto a balcony, porch, or terrace and they may provide an entrance to a garden.
A louvred door has fixed or movable wooden fins (often called slats or louvers) which permit open ventilation while 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. Double louvred doors were introduced into Seagate, built in Florida in 1929 by Gwendolyn and Powel Crosley, that provided the desired circulation of air with an added degree of privacy in that it is impossible to see through the fins in any direction.
A composite door is a single leaf door that can be solid or with glass, and is usually filled with high density foam. In the United Kingdom, it is common for composite doors to be certified to BS PAS 23/24 and be compliant with Secured by Design.
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. Skins can also be made out of hardboards, the first of which was invented by William H Mason in 1924. Called Masonite, its construction involved pressing and steaming wood chips into boards. 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 MDF. Skins can also be made out of hardboards.
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).
A wicket door is a pedestrian door built into a much larger door allowing access without requiring the opening of the larger door. Examples might be found on the ceremonial door of a cathedral or in a large vehicle door in a garage or hangar.
A bifold door is a door unit that has several sections, folding in 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.
Australian doors are a pair of plywood swinging doors often found in Australian public houses. These doors are generally red or brown in color and bear a resemblance to the more formal doors found in other British Colonies' public houses.
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).
Most doors are hinged along one side to allow the door to pivot away from the doorway in one direction but not in the other. The axis of rotation is usually vertical. In some cases, such as hinged garage doors, the axis may be horizontal, above the door opening.
Doors can be hinged so that the axis of rotation is not in the plane of the door to reduce the space required on the side to which the door opens. This requires a mechanism so that the axis of rotation is on the side other than that in which the door opens. This is sometimes the case in trains or airplanes, such as for the door to the toilet, which opens inward.
A swing doors has special hinges that allow it to open either outwards or inwards, and is usually sprung to keep it closed.
A selfbolting door is called as such because of its special hinges that permit the panel leaf to move laterally so that the door itself becomes a giant bolt for better security result. The selfbolting door principle can be used both for hinged doors as for rotating doors, as well as up-and-over doors (in the latter case, the bolts are then placed at top and bottom rather than at the sides).
French doors are derived from an original French design called the casement door. It is a door with lites where all or some panels would be in a casement door. A French door traditionally has a moulded panel at the bottom of the door. Called a French window when used in pairs as double-leaved doors with large glass panels in each door leaf, and in which the doors may swing out (most typical) as well as in.
Dutch door or stable door; the top half of the door operates independently from the bottom half. A variant exists in which opening the top part separately is possible, but because the lower part has a lip on the inside, closing the top part, while leaving the lower part open, is not.
Garden door resembles a French window (with lites), but is more secure because only one door is operable. The hinge of the operating door is next to the adjacent fixed door and the latch is located at the wall opening jamb rather than between the two doors or with the use of an espagnolette bolt.
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".
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.
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.
In North America, the Door and Access Systems Manufacturing Association (DASMA) defines high-performance doors as non-residential, powered doors, characterized by rolling, folding, sliding or swinging action, that are either high-cycle (minimum 100 cycles/day) or high-speed (minimum 20 inches(508 mm)/second), and two out of three of the following: made-to-order for exact size and custom features, designed to be able to withstand equipment impact (break-away if accidentally hit by vehicle) or designed to sustain heavy usage with minimal maintenance.
Up-and-over or overhead doors are 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 roller shutter or sectional overhead door is one variant of this type.
A tambour door or roller door is an up-and-over door made of narrow horizontal slats and "rolls" up and down by sliding along vertical tracks and is typically found in entertainment centres and cabinets.
Automatically opening doors are powered open and closed either by electricity, spring, or both. There are several methods by which an automatically opening door is activated:
In addition to activation sensors automatically opening 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 from colliding with an object in its path by stopping or slowing its motion.
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, building occupants would be prevented from escaping. In commercial and retail situations manufacturers have included in the design a mechanism that allows an inward opening door to be pushed open outwards in the event of an emergency (which is often a regulatory requirement). This is known as a 'breakaway' feature. Pushing the door outward at its closed position, through a switch mechanism, disconnects power to the latch and allows the door to swing outward. Upon returning the door to the closed position, power is restored.
Rebated doors, a term chiefly used in Britain, are double doors having a lip or overlap (i.e. a Rabbet) on the vertical edge(s) where they meet. Fire-rating can be achieved with an applied edge-guard or astragal molding on the meeting stile, in accordance with the American Fire door.
Evolution Door is a trackless door that moves in the same closure level as a silding door. The system is an invention of the Austrian artist Klemens Torggler. From the technical point of view the Evolution Door is a further development (evolution) of the Drehplattentür or flip panel door that normally consists of two rotatable, connected panels which move to each other when opening.
Architectural doors have numerous general and specialized uses. Doors are generally used to separate interior spaces (rooms, closets, etc.) for privacy, convenience, security, and safety reasons. Doors are also used to secure passages into a building from the exterior for reasons of safety and climate control.
Doors also are applied in more specialized cases:
Panel doors, also called stile and rail doors, are built with frame and panel construction. EN 12519 is describing the terms which are officially used in European Member States. The main parts are listed below:
Plank and batten doors are an older design consisting primarily of vertical slats:
This type consists of vertical tongue and grooved boards held together with battens and diagonal braces.
Impact-resistant doors have rounded stile edges to dissipate energy and minimize edge chipping, scratching and denting. The formed edges are often made of an engineered material such as Acrovyn. Impact-resistant doors excel in high traffic areas such as hospitals, schools, and hotels.
This type 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.
Many modern doors, including most interior doors, are flush doors:
Door swings For most of the world, door swings, or handing, are determined while standing on the outside or less secure side of the door while facing the door (i.e., standing on the side you use the key on, going from outside to inside, or from public to private).
It is especially important to get the hand and swing right on exterior doors, as the transom is usually sloped and sealed to resist water entry, and to properly drain. In some custom millwork (or with some master carpenters), the manufacture or installer will bevel the leading edge (the first edge to meet the jamb as the door is closing) so that the door fits tight without binding. Specifying an incorrect hand and/or swing will cause the door to bind, not close properly, or leak (for exterior doors). Fixing this specification error will be expensive and/or time consuming. See note below for Australia where a different orientation is used.
In North America, many doors now come with factory-installed hinges, pre-hung on the jamb and sills.
To determine hand, stand on the outside (or less secure) side of the door. While facing the door, if the hinge is on the right side of the door, the door is "Right handed"; or if the hinge is on the left, it is "Left handed".
If the door swings toward you, it is "Reverse swing"; or if the door swings away from you, it is "Normal swing".
In other words:
Note: In Australia, this is different. The refrigerator rule applies (you can't stand in a fridge, the door always opens towards you) - If the hinges are on the left then its a left hand (or left hung) door. If the hinges are on the right then its a right hand (or right hung) door. See the Australian Standards for Installation of Timber Doorsets, AS 1909-1984 pg 6.
In public buildings, exterior doors should open to the outside in order to comply with any fire codes that may be in force in that jurisdiction. If the door opens inward and there is a fire, there can be a crush of people who run for the door and they will not be able to open it.
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|The examples and perspective in this article may not represent a worldwide view of the subject. (September 2010)|
A standard US residential door size is 36" x 80" (91 x 203 cm).
Exterior and passage (room to room) doors: Standard door sizes in the US are from 2'-6" to 3'-0" wide, increasing in 2" increments. Most residential interior doors are 2'-6" (0.76 m) wide except when designed to allow wheelchair access, then 3'-0" (0.91). Residential doors are often 6'-8" high, as are many small stores, offices, and other light commercial buildings. Larger commercial, public buildings and grand homes often use doors of greater height. Older buildings often have smaller doors.
Closets: small spaces such as closets, dressing rooms, half-baths, storage rooms, cellars, etc. often are accessed through doors smaller than passage doors in one or both dimensions but similar in design.
Garages: Garage doors are generally 7'-0" or 8'-0" wide for a single-car opening. Two car garage doors (sometimes called double car doors) are a single door 16'-0". Because of size and weight these doors are usually sectional. That is split into four or five horizontal sections so that the can be raised more easily and don't require a lot of additional space above the door when opening and closing. There are single piece double garage doors found in some older homes. circa 1950's
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 section, one of the sections may be called a leaf. See door furniture for a discussion of attachments to doors such as door handles and doorknobs.
Door furniture or hardware refers to any of the items that are attached to a door or a drawer to enhance its functionality or appearance. This includes items such as hinges, handles, door stops, etc.
Door safety relates to prevention of door-related accidents. Such accidents take place in various forms, and in a number of locations; ranging from car doors to garage doors. Accidents vary in severity and frequency. According to the National Safety Council in the United States, 300,000 injuries are caused by doors every year.
The types of accidents vary from relatively minor cases where doors cause damage to other objects, such as walls, to serious cases resulting in human injury, particularly to fingers. A closing door can exert up to 40 tons per square inch of pressure between the hinges. Because of the number of accidents taking place, there has been a surge in the number of lawsuits. Thus organisations may be at risk when car doors or doors within buildings are unprotected.
According to the US General Services Administration:
Whenever a door is opened outwards there is a risk that it could strike another person. In many cases this can be avoided by architectural design which favors doors which open inwards into rooms (from the perspective of a common area such as a corridor, the door opens outwards). In cases where this is infeasible, it may be possible to avoid an accident by placing windows in the door.
However, inward-hinged doors can also escalate an accident by preventing people from escaping the building: people inside the building may press against the doors, and thus prevent the doors from opening. This was partly the case in the Grue Church fire in Norway in 1822.
Today, the exterior doors of most large (especially public) buildings open outward, while interior doors such as doors to individual rooms, offices, suites, etc. open inward, as do many exterior doors of houses, particularly in North America.
Doorstops are simple devices used to prevent a door from coming into contact with another object (typically a wall). Without the door stop damage might be done to the wall. They may either absorb the force of a moving door, or hold the door in place to prevent unintended motion.
The purpose of door guards (also known as hinge guards, anti-finger trapping devices, or finger guards) is to reduce the number of finger trapping accidents in doors, as doors pose a risk to children especially when closing. Door guards protect fingers in door hinges by covering the gap that is created by opening doors by covering the hinges of doors with a piece of rubber or plastic that wraps from the door frame to the door. There are also door safety products which eject the fingers from the push side of the door as it is being closed.
There are various levels of door protection. Front door protection a front anti-finger trapping device but leaves the rear hinge pin side of the door unprotected. Full door protection uses front and rear anti-finger trapping devices and ensures the hinge side of a door is fully protected. Which level of protection is appropriate should be determined by a risk assessment of the door.
There is also handle-side door protection, which prevents the door from slamming shut on the frame, which can cause injury to fingers/hands.
A safety door prevents finger injuries near the hinges without the use of door guards. Rather than cover the danger area, the approach is to change the shape of the door so that an accessible gap does not form in the first place. This is achieved by adding a perfectly circular ("bull-nose" shaped) extension to the door, which moves in and out of a cavity as the door opens and closes. This prevents any part of a hand being crushed near the hinges - either inside or outside. These doors have an operating range of slightly over 90 degrees, so their use is limited to where they come into contact with a side wall when fully open (or where they can be prevented from opening too far by a doorstop).
Glass doors pose the risk of unintentional collision if a person believes the door to be open when it is closed, or is unaware there is a door at all. This risk may be particularly pronounced with sliding glass doors because they often have large single panes which are hard to see. To prevent injury from glass doors, stickers or other types of warnings are sometimes placed on the glass surface to make it more visible. For instance, in the UK, Regulation 14 of the Workplace (Health and Safety Regulations) 1992 requires the marking of windows and glass doors to make them conspicuous. Australian Standards: AS1288 and AS2208 require glass doors to be made from laminated or toughened glass.
Special purpose fire doors are often employed in buildings to reduce the overall risk of fire, particularly by preventing the spread of fire and smoke. In cases where they are improperly installed, employed, or tampered with, the risk of fire can be increased. Door closers are sometimes used to ensure fire doors remain closed.
An additional risk in a fire is that doors may prevent access to emergency services personnel in order to fight the fire, rescue occupants, etc. Door breaching techniques may be required in these situations to gain access.
Panic bars are often used in buildings so that a door locked from the exterior can quickly and easily be opened from the inside in the event of a fire or other emergency.
There may be an increased risk of trapping hands or fingers in car doors compared to other types of doors. In some car accidents, injury to occupants from the movement of car doors may occur.
Bicyclists often fear collision with an opening car door in case the car's occupant does not look carefully to check that it is safe to open the door. Because cyclists often ride near parked cars along the side of the road (see door zone) they are particularly vulnerable.
Doors which lead from interior, pressurized, sections of an aircraft to exterior or unpressurized areas can pose extreme risk if they are inadvertently opened during flight. This can be mitigated by having doors that open inwardly and are designed to be forced into their door frames by the internal cabin pressure - most cabin doors are of this type. However, an outward opening door is often advantageous for cargo doors to maximise available space, and these need to be secured by hefty locking mechanisms to overcome internal pressure.
A number of accidents have occurred where outward-opening aircraft doors were opened in flight, often accidentally:
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