A revolving door typically consists of three or four doors that hang on a central shaft and rotate around a vertical axis within a cylindrical enclosure. Revolving doors are energy efficient as they, acting as an
airlock
An airlock, air-lock or air lock, often abbreviated to just lock, is a compartment with doors which can be sealed against pressure which permits the passage of people and objects between environments of differing pressure or atmospheric compo ...
, prevent drafts, thus decreasing the loss of heating or cooling for the building. Revolving doors were designed to relieve the immense pressure caused by air rushing through high-rise buildings (referred to as
stack effect pressure) while at the same time, to allow large numbers of people to pass in and out.
Construction
Around the central shaft of the revolving door, there are usually three or four panels called "wings" or "leaves." Large diameter revolving doors can accommodate strollers and wheeled luggage racks.
Some "revolving door displays" incorporate a small glass enclosure, permitting small objects such as sculpture, fashion
mannequins
A mannequin (also called a dummy, lay figure, or dress form) is a doll, often articulated, used by artists, tailors, dressmakers, window dressers and others, especially to display or fit clothing and show off different fabrics and textiles. Pr ...
, or plants to be displayed to pedestrians passing through. Such enclosures can either be mounted at the central pivot, or attached to the revolving door wings.
The wings of revolving doors usually incorporate glass, to allow people to see and anticipate each other while passing through the door. Manual revolving doors rotate with pushbars, causing all wings to rotate. Revolving doors typically have a "speed control" (
governor
A governor is an administrative leader and head of a polity or political region, ranking under the head of state and in some cases, such as governors-general, as the head of state's official representative. Depending on the type of political ...
) to prevent people from spinning the doors too fast.
Automatic revolving doors are powered above/below the central shaft, or along the perimeter. Automatic revolving doors have safety sensors, but there has been at least one fatality recorded.
Skyscraper
A skyscraper is a tall continuously habitable building having multiple floors. Modern sources currently define skyscrapers as being at least or in height, though there is no universally accepted definition. Skyscrapers are very tall high-ris ...
design requires a means of draft block, such as revolving doors, to prevent the
chimney effect
The stack effect or chimney effect is the movement of air into and out of buildings through unsealed openings, chimneys, flue-gas stacks, or other containers, resulting from air buoyancy. Buoyancy occurs due to a difference in indoor-to-outdoor ...
of the tall structure from sucking in air at high speed at the base and ejecting it through vents in the roof while the building is being heated, or sucking in air through the vents and ejecting it through the doors while being cooled, both effects due to convection. Modern revolving doors permit the individual doors of the assembly to be unlocked from the central shaft to permit free flowing traffic in both directions. This feature, called "breakout" or "break away", is typically used only during emergencies, or to admit oversize objects. The most effective method for this is the "bookfold" design, which allows all 3 or 4 wings to be broken away together. Normally, the revolving door is always closed so that wind and drafts cannot blow into the building, to efficiently minimize
heating and air conditioning loads.
In
right hand traffic countries, revolving doors typically revolve counter-clockwise (as seen from above), allowing people to enter and exit only on the right side of the door. In
left hand traffic countries such as Australia and New Zealand, revolving doors revolve clockwise, but door rotations are mixed in Britain. Direction of rotation is often enforced by the door governor mechanism, or by the orientation of the door seal brush (weatherstrips).
Security
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" behind an authorized person. Extreme security can require a particular type of bullet-resistant glass.
Sometimes a revolving door is designed for
one-way traffic
One-way traffic (or uni-directional traffic) is traffic that moves in a single direction. A one-way street is a street either facilitating only one-way traffic, or designed to direct vehicles to move in one direction. One-way streets typical ...
. An example is the now-common usage in
airports
An airport is an aerodrome with extended facilities, mostly for commercial air transport. Airports usually consists of a landing area, which comprises an aerially accessible open space including at least one operationally active surface ...
to prevent a person from bypassing
airport security
Airport security includes the techniques and methods used in an attempt to protect passengers, staff, aircraft, and airport property from malicious harm, crime, terrorism, and other threats.
Aviation security is a combination of measures and hum ...
checkpoints by entering the exit. Such doors are designed with a
brake
A brake is a mechanical device that inhibits motion by absorbing energy from a moving system. It is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of friction.
Background ...
that is activated by a sensor should someone enter from the incorrect side. The door also revolves backwards to permit that person to exit, while also notifying security of the attempt.
Turnstile
A turnstile (also called a turnpike, gateline, baffle gate, automated gate, turn gate in some regions) is a form of gate which allows one person to pass at a time. A turnstile can be configured to enforce one-way human traffic. In addition, a t ...
exit-only doors are also often used in
subways and other
rapid transit
Rapid transit or mass rapid transit (MRT), also known as heavy rail or metro, is a type of high-capacity public transport generally found in urban areas. A rapid transit system that primarily or traditionally runs below the surface may be c ...
facilities to prevent people from bypassing fare payment. They are similarly used at large
sports stadiums,
theme park
An amusement park is a park that features various attractions, such as rides and games, as well as other events for entertainment purposes. A theme park is a type of amusement park that bases its structures and attractions around a central ...
s, and other such venues, to allow pedestrians to exit freely, but not to enter without paying admission fees. These doors usually work mechanically, with the door panels constructed of horizontal bars which pass through a "wall" of interlacing (interdigitated) bars, allowing the door leaves to pass through, but blocking people from illegally entering through the exit.
Emergency use
In 1942, the
Cocoanut Grove, a popular nightclub in
Boston
Boston (), officially the City of Boston, is the state capital and most populous city of the Commonwealth of Massachusetts, as well as the cultural and financial center of the New England region of the United States. It is the 24th- mo ...
,
, went up in flames killing 492 people. One of the main reasons cited for the large number of casualties was the single revolving door located at the entrance. As the mob of panicking patrons attempted to use the door as an escape it soon became jammed, trapping countless people between the door and the crowd pushing towards it. As a result, many people died from
smoke inhalation
Smoke inhalation is the breathing in of harmful fumes (produced as by-products of combusting substances) through the respiratory tract. This can cause smoke inhalation injury (subtype of acute inhalation injury) which is damage to the respirator ...
, as they were not able to escape the burning nightclub.
In 1943, it became a Massachusetts state law requirement to flank a revolving door with an outward swinging hinged door or to 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
Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...
Building Code
A building code (also building control or building regulations) is a set of rules that specify the standards for constructed objects such as buildings and non-building structures. Buildings must conform to the code to obtain planning permission ...
3.4.6.14. asserts that revolving doors needs to "(a) be collapsible, (b) have hinged doors providing equivalent exiting capacity located adjacent to it".
History
H. Bockhacker of
Berlin
Berlin ( , ) is the capital and largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's most populous city, according to population within city limits. One of Germany's sixteen constitue ...
was granted German patent DE18349 on December 22, 1881 for "''Tür ohne Luftzug''" or "Door without draft of air", which used a rotating cylinder with a door which after entering, the user then turned around to the exiting direction.
Theophilus Van Kannel, of Philadelphia, was granted US patent 387,571 on August 7, 1888 for a "Storm-Door Structure". The
patent drawing
A patent application or patent may contain drawings, also called patent drawings, illustrating the invention, some of its embodiments (which are particular implementations or methods of carrying out the invention), or the prior art. The drawings ...
s 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". An urban legend, dating back to perhaps 2008, claims that the invention was motivated by his phobia of opening doors for others, especially women; according to
Snopes
''Snopes'' , formerly known as the ''Urban Legends Reference Pages'', is a Fact checking, fact-checking website. It has been described as a "well-regarded reference for sorting out myths and rumors" on the Internet. The site has also been see ...
, there is no evidence that this claim is true.
In 1889, the
Franklin Institute
The Franklin Institute is a science museum and the center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and statesman Benjamin Franklin. It houses the Benjamin Franklin National Memori ...
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
Times Square is a major commercial intersection, tourist destination, entertainment hub, and neighborhood in Midtown Manhattan, New York City. It is formed by the junction of Broadway, Seventh Avenue, and 42nd Street. Together with adjacent ...
in Manhattan, located on Broadway between West 43rd and 44th Streets. In 2007 Theophilus Van Kannel was inducted into the
National Inventors Hall of Fame
The National Inventors Hall of Fame (NIHF) is an American not-for-profit organization, founded in 1973, which recognizes individual engineers and inventors who hold a U.S. patent of significant technology. Besides the Hall of Fame, it also opera ...
for this invention.
Research
Research into the air and energy exchanges associated with revolving door usage have been carried out on a few occasions. The earliest such study was carried out in 1936 by A. M. Simpson, who worked for the van Kannel revolving door company at the time. Simpson's study was followed by a study by Schutrum et al.
in 1961, and more recently a study by van Schijndel et al. in 2003. These studies have focused on providing detailed measurements of the quantities of air and heat transferred inside the compartments of a door as it revolves. With the exception of the study by van Schijndel et al., which was purely theoretical, the measurements carried out for the other studies were used to provide design charts enabling engineers to estimate the quantity of air transferred by a door in function of the revolution rate and temperature contrast. Unfortunately, none of these studies appear to be referenced by existing design codes.
Although the aforementioned studies provide useful results, these results are also specific to the type of door which they were acquired for, namely 2m x 2m doors with four compartments. Although it appears that these dimensions were standard for four-compartment doors at the time, this is not the case nowadays. A more recent experimental study
carried out at Imperial College London's Department of Civil and Environmental Engineering, has provided more insight into the flow physics by which air is transferred across a revolving door.
Airflows and energy losses through revolving doors also occur as a result of leakages past the seals of the door. Leakages are common to any type of opening in an otherwise closed space, but have been investigated in the context of revolving doors by Zmeureanu et al. and by Schutrum et al.
before that. The first study concluded that to avoid significant leakages, the seals of the doors should be maintained and periodically replaced if needed. The second study produced design charts for estimating the leakage rate through a revolving door. Unlike the curves for estimating the transfer rate also published in this study, the curves for estimating the leakage rate are more generic. As such these design curves still form the basis of the target leakage rates for revolving doors recommended by the
ASHRAE standard 90.1 in the US. On May 25, 2006, an MIT Study entitled "Modifying Habits Towards Sustainability: A Study of Revolving Doors Usage on the MIT Campus" was published. In it, B. A. Cullum, Olivia Lee, Sittha Sukkasi and Dan Wesolowski concluded, "...substantial energy is saved when people use the revolving doors instead of swing doors - the smallest of habit changes contributes to energy conservation... Modification of one habit... indeed has the ability to eventually impact the environment on a global scale."
While preferred by building owners for energy conservation, revolving doors may be avoided by some people due to the perceived greater physical effort in using them.
See also
*
Revolving door (politics)
In politics, a revolving door is a situation in which personnel move between roles as legislators and regulators, on one hand, and members of the industries affected by the legislation and regulation, on the other, analogous to the movement of pe ...
*
Turnstile
A turnstile (also called a turnpike, gateline, baffle gate, automated gate, turn gate in some regions) is a form of gate which allows one person to pass at a time. A turnstile can be configured to enforce one-way human traffic. In addition, a t ...
*
Paternoster lift
A paternoster (, , or ) or paternoster lift is a passenger elevator which consists of a chain of open compartments (each usually designed for two people) that move slowly in a loop up and down inside a building without stopping. Passengers can ...
References
Further reading
* Alan Beadmore, ''The Revolving Door since 1881: Architecture in Detail'', 2000,
* Harvey E. Van Kannel and Joanne Fox Marshall, ''T. Van Kannel, the inventor : his autobiography and journal'', 1988,
External links
Sustainability/Energy Savings/Stack pressures (MIT study)
{{DEFAULTSORT:Revolving Door
American inventions
Doors
1899 introductions
Articles containing video clips
Door
A door is a hinged or otherwise movable barrier that allows ingress (entry) into and egress (exit) 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 b ...