A revolving door typically consists of three or four doors that hang on a center shaft and rotate around a vertical axis within a round enclosure. Revolving doors are energy efficient by eliminating drafts, thus reducing the heating or cooling required for the building. At the same time, revolving doors allow large numbers of people to pass in and out.
The glass doors allow people to see and anticipate each other while walking through. Manual revolving doors rotate with pushbars causing all wings to rotate. Revolving doors typically have a "speed control" (governor) to prevent people from spinning the doors too fast.
Skyscrapers have required revolving doors because the sudden volume of rushing air can be so great as to blow out windows. Modern versions permit the individual doors of the assembly to be unlocked from the central shaft to permit free flowing traffic in both directions. The revolving door is always closed, so wind and drafts cannot blow into the building, also efficiently minimizing heating and air conditioning.
In right hand drive countries, revolving doors typically revolve counter-clockwise, allowing people to enter and exit only on the right side of the door. In left hand drive countries, revolving doors should revolve clockwise but not always
Revolving doors can also be used as security devices to restrict entry to a single person at a time if the spacing between the doors is small enough. This is in contrast to a normal door which allows a second person to easily "tailgate" an authorized person. Extreme security can require bullet-proof glass.
Sometimes a revolving door is designed for one-way traffic. An example is the now-common usage in airports to prevent a person from bypassing airport security checkpoints by entering the exit. Such doors are designed with a brake that is activated by a sensor should someone enter from the incorrect side. The door also revolves backwards to permit the person to exit, while also notifying security of the attempt.
Turnstile doors are also often used in subways and other rapid transit facilities to prevent people from avoiding a fare. These doors usually work mechanically with the door panels constructed of horizontal bars which pass through a bar "wall", allowing the door to pass through but not people.
H. Bockhacker of Berlin was granted German patent DE18349 on December 22, 1881 for "Thür ohne Luftzug" or "Door without draft of air".
Theophilus Van Kannel, of Philadelphia, was granted US patent 387,571 on August 7, 1888 for a "Storm-Door Structure". The patent drawings filed show a three-partition revolving door. The patent describes it as having "three radiating and equidistant wings . . . provided with weather-strips or equivalent means to insure a snug fit". The door "possesses numerous advantages over a hinged-door structure . . .it is perfectly noiseless . . . effectually prevents the entrance of wind, snow, rain or dust . . ." "Moreover, the door cannot be blown open by the wind . . . there is no possibility of collision, and yet persons can pass both in and out at the same time." The patent further lists, "the excluding of noises of the street" as another advantage of the revolving door. It goes on to describe how a partition can be hinged so as to open to allow the passage of long objects through the revolving door. The patent itself does not use the term "revolving door".
"In 1889, the Franklin Institute of Philadelphia awarded the "John Scott Legacy Medal" to Van Kannel for his contribution to society." "In 1899, the world’s first wooden revolving door was installed at Rector’s, a restaurant on Times Square in Manhattan, located on Broadway between West 43rd and 44th Streets."
In 1943 it became Massachusetts state law to either flank a revolving door with an outward swinging hinged door or make the revolving door collapsible (so it becomes a double partition collapsing at 180°) allowing people to pass on either side. American revolving doors are now collapsible. Some jurisdictions require them to be flanked by at least one hinged door either by common practice or required by law. For example, the Ontario Building Code 126.96.36.199. asserts that revolving doors needs to "(a) be collapsible, (b) have hinged doors providing equivalent exiting capacity located adjacent to it"