Door: Encyclopedia II - Door - Types of doors

Door - Types of doors

A door may slide or rotate. Sliding is usually horizontal. In the case of rotation, the axis of rotation 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.

A blind door is a door with no passage, a 'fake' door that is actually part of the wall. It is used for decorative purposes.

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 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 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.

A sliding glass door is a glass door that slides to open. A similar sliding door, though often not made of glass and in the interior of the building, is called a pocket door.

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 three or four panels that meet in the center and rotate one way about a vertical axis (sometimes the movement is not in a circle, but following a more complicated path, a combination of rotation and translation). Between the point of access and the point of exit the user walks between two moving panels. The door may be motorized or the user needs to push the front panel, and the space between two panels may be designed for multiple users or a single one. 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 to install their own revolving doors when a rival building gets one.

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.

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 infra-red 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 infra red 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 manualy, 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.

In addition to activate sensors automatic doors are generally fitted with safety sensors. These are usually an infra-red 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 first automatic door.

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

Adapted from the Wikipedia article "Types of doors", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki