revolving door

1. A door, as in the entrance of an office or apartment building, usually consisting of four rigid upright sections interconnected at right angles and rotating about a central upright pivot.
2. Informal. An organization, institution, or place whose members, personnel, or population remain only a short time before going elsewhere.

Background

A revolving door is used to control traffic or heating and air conditioning in a building. The revolving door structure consists of individual door panels (or wings), a center shaft with the hardware needed to support the door wings, a circular structure called a "rotunda" or "drum" that is usually fitted with glass, and the ceiling (supported by the rotunda) that contains either a mechanical braking device (used to control the speed of the doors) or an electronic device that uses a motor to drive the doors automatically.

The main benefit of a revolving door is that it is always closed and always open. This means that the design of the system is such that there is at least one door wing sealing the opening at all times reducing the amount of heating volume and air conditioning (HVAC) that escapes from a building and these savings in energy costs can be considerable. The revolving door achieves these savings because the curved walls of the rotunda allow the seals to fit tightly as the door wings rotate.

Each wing is fitted with a rubber and felt weather seal. With time and use, these weather seals on the door wings must be replaced because their effectiveness diminishes with age. This process is also a part of the design of the revolving door system.

History

The exact first use of revolving doors is unknown. However, it is known that they have been in use since about 1790 in Chicago where they are still widely used today. Revolving doors solved the problem of how to automatically close the door opening in order to keep from losing heating or cooling. Early revolving doors were manufactured using wood because the technology and materials needed to economically manufacture them from metal was either not yet available or prohibitively expensive.

Raw Materials

The materials used in the construction of a revolving door consist of aluminum extrusion, steel tubes, machined steel hardware pieces designed to attach the doors to the structure, marine grade plywood, glass (curved and flat), felt and rubber, and the mechanical devices used to control speed or a motor driven operator device to move the doors in response to a signal from a sensor.

Design

Each basic revolving door design is modified (with respect to dimensions, number of door wings, whether the function is manual, automatic or security, and finish or color) to suit the users requirements. The basic design of the revolving door system is not changed, but it is available in several configurations. When an architect specifies a revolving door, he or she is primarily interested in the best design that will conserve energy but also one that will bet suit the traffic requirements of the finished building. From this basic idea, the architect specifies the revolving door system and configuration, and manufacturers can adapt their designs to comply with the specifications.

The Manufacturing
Process

1. All aluminum members are cut to length depending on the overall final dimensions of the revolving door. Aluminum extrusions are manufactured utilizing a very large press device called an extrusion press. The press forces pre-heated aluminum cast billets through a steel die that has a shape cut to the requirements of the user. Much the same as a cake decorator who uses a sack of icing forced through a small nozzle to create designs and shapes, an extrusion takes the shape of the cut out in the die and these shapes can be made to very exact tolerances. These extrusions are the main components used in revolving door manufacturing—they are designed to lock together and provide a very solid framework to support the rest of the system.

   Revolving door systems can also be manufactured using exotic metals like brass or stainless steel to enhance their appearance. These systems do not use aluminum extrusions. Instead, sheets of metal that are cut and formed to wrap around a steel skeleton (sub-frame) are welded in place. They can easily cost as much as three times that of a standard aluminum revolving door.

2. The circular rotunda walls are formed from aluminum extrusions that are repeatedly fed through a bending machine until the correct radius is achieved. The radius depends on the required size of the revolving door. The most common size (width) is 8 ft (2.4 m), but these systems can be manufactured to much larger widths. Larger systems are usually motorized because the structure would be very difficult to push manually.

   The bending machine consists of three rollers through which the straight piece of aluminum is fed. After each bend, the rollers are moved closer together and the material is fed through again until the correct radius is achieved. This process is critical because the door panels must not only fit inside the rotunda, but they must also evenly rotate 360 degrees without hitting the rotunda walls. The seal between the door panels and the rotunda must also be maintained to reduce the amount of hot and cold air entering and leaving through the door.

3. All aluminum parts (doors, frames, etc.) are welded together and prepared to receive the hardware components that make up the emergency breakout system.
4. The circular ceiling is cut from 1 in (2.54 cm) thick marine grade plywood and then laminated with 0.125 in (0.318 cm) thick aluminum sheet to form the interior ceiling.
5. The ceiling is prepared for the light fixtures (cut-outs) and the center shaft hole is cut at the very center.
6. Steel angle is welded together in a grid pattern to provide the support for the ceiling and to secure the mechanical speed control device. The grid is installed on top of the ceiling.

   The speed control device is a system of spring loaded brake shoe assembly that rotates inside a drum. As the rotational speed of the revolving door increases, so does the brake shoe assembly and the pressure of the brake shoes against the drum slows the revolving door down preventing the "freewheeling" effect. The speed control device can be mounted in the ceiling or in the floor. Floor mounted speed controls are used on systems that have glass ceilings or have insufficient clearance at the top of the door system.

7. The center shaft is fabricated and fitted with the balance of the breakout hardware. Revolving door systems (in the United States) must be fitted with a "panic collapsing mechanism" or "breakout system" that permits the door frames to fold against one another. This bookfold position permits an unobstructed exit from the interior to the exterior of the building in the event of a fire or other emergency. The Uniform Building Code (adopted by most municipalities in the United States) requires the breakout system together with another manual or automatic swinging or sliding door next to the revolving door for emergency exit and handicap access.

   The breakout mechanism consists of two breakout plates that are attached to each end of the center shaft. They are slotted because the door frames are fitted with pivot bars that allow the door frame to fold out of position as described above. The breakout plates have removable access gates that allow the door frame to be hung to the assembly using a pivot bar assembly.

   The revolving door panels rotate with the center shaft assembly and the center shaft assembly is, as previously discussed, fitted with breakout plates at the top and bottom. There are additional hardware devices at each end of the center shaft and these devices are the actual center shaft pivot points. They are referred to as stub shafts.

   The bottom of the center shaft assembly sits inside a bearing assembly that is secured to the floor of the building. The bearing permits the revolving door to rotate smoothly and is necessary to prevent mechanical breakdown due to wear.

8. The entire revolving door is assembled at the factory for testing. Once cleared for shipment, the revolving door is disassembled and wrapped in protective plastic. A wood crate is built and the revolving door components are packed and secured for their journey to the job site.

Quality Control

When the revolving door assembly is erected, a series of tests and measurements are made in order to verify that the product conforms to the requirements of the customer. The system is checked for correct height and width, all functions of the revolving door are tested (speed control, breakout system, weather stripping, etc.) and adjustments are made where needed. In the case of security systems or automatic systems, each computer function or mode of operation is checked and re-checked for proper operation. The quality control inspector must sign off on an inspection form before the door system can be disassembled.

Byproducts/Waste

All waste materials are recyclable and consist of wood, aluminum and steel. All waste material is stored and sent to a recycling center. There are no harmful chemicals used or wastes in the manufacturing process.

The Future

Designs are being examined that would incorporate enhanced security features for specialty applications such as airports and prisons to include metal and chemical detection systems as well as new video recognition systems. Although the revolving door basic design remains the same after over 200 years of use, some new door systems are very large (20 ft [6.1 m] in diameter) and their design incorporates elaborate and exotic electromechanical devices designed to allow several people to transverse the opening at once, where most revolving door designs accommodate one or two people at a time. The mechanical limitations of the equipment make the large door systems expensive to own and troublesome to maintain and repair. Revolving doors will always be the best way to control HVAC loss in areas that experience extremes of climate but they will also remain effective for access control and traffic control well into the future.

Where to Learn More

Other

Manfredi, Bob. Revolving Doors: An Open And Shut Case. December 2001. <http://www.greendesign.net/bcnews/SEPOCT96/rvlvgdrs.htm>

Sierra Automatic Doors, Inc. Web Page. December 2001. <http://www.autodoors.com>.

[Article by: O. Harold Boutilier]

An exterior door consisting of four leaves (at 90° to each other) which pivot about a common vertical axis within a cylindrically shaped vestibule; prevents the direct passage of air through the vestibule, thereby eliminating drafts from outside.

revolving door: plan

For other uses, see Revolving door (disambiguation).

A revolving door in Turkey (counter-clockwise rotation)

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.^[1] At the same time, revolving doors allow large numbers of people to pass in and out.

Revolving doors are also often seen as a mark of prestige and glamour for a building and its architecture.^{[citation needed]}

Contents 1 Construction 2 History 3 As a fire exit 4 References 5 Further reading 6 See also 7 External links

Construction

Around the center shaft of the revolving door, there are usually three or four doors called "wings" or "leaves". Large diameter revolving doors can accommodate strollers and luggage racks. The tallest revolving door currently is about 16 feet (4.9 m) high with 4 wings.^[2]

An unusual pair of revolving doors at City Hall in London: one revolves clockwise; the other revolves counterclockwise.

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.

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.^[3]

Skyscraper design requires revolving doors to prevent the chimney effect of the tall structure from sucking in air at high speed at the base and ejecting it through vents in the roof. 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 loads.

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.^[4]

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.

A revolving door, from above.

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.

History

Revolving doors are favored because they can be used as an airlock to minimize a building's heating and air conditioning losses.

H. Bockhacker of Berlin was granted German patent DE18349^[5] on December 22, 1881 for "Tür 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."^[6] 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.^[7]. In 2007 Theophilus Van Kannel was inducted into the Inventors Hall of Fame for this invention.^[8]

As a fire exit

In 1942, the Cocoanut Grove, a popular nightclub in Boston, Massachusetts, USA, went up in flames killing 503 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, not being able to escape the burning nightclub.

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 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".^[9]

References

1. ^ Revolving Doors - Sustainability @ MIT
2. ^ ehotelier.com. "Hotel News In Brief | ehotelier.com News Archives". Ehotelier.com. http://ehotelier.com/browse/news_more.php?id=A9942_0_11_0_M. Retrieved 2009-07-08. 
3. ^ "About automatic door accident at Roppongi Hills - MORI BUILDING". Web.archive.org. http://web.archive.org/web/20080126101814/http://www.mori.co.jp/apology/en_040328.html. Retrieved 2009-07-08. 
4. ^ "Which side of the road do they drive on?". Brianlucas.ca. http://www.brianlucas.ca/roadside/. Retrieved 2009-07-08. 
5. ^ "esp@cenet — Original document". V3.espacenet.com. http://v3.espacenet.com/publicationDetails/originalDocument?CC=DE&NR=18349C&KC=C&FT=D&date=&DB=EPODOC&locale=en_V3. Retrieved 2009-07-08. 
6. ^ International Revolving Door Company Overview at the Internet Archive
7. ^ The city in slang: New York life and popular speech. Irving Lewis Allen. Publisher: New York ; Oxford University Press, 1993. Page 126. ISBN 0195092651
8. ^ ""Inventors Hall of Fame". http://invent.org/hall_of_fame/368.html. 
9. ^ [1]

Further reading

• Alan Beadmore, The Revolving Door since 1881: Architecture in Detail, 2000, ISBN 90-901374-3-2
• Harvey E. Van Kannel and Joanne Fox Marshall, T. Van Kannel, the inventor : his autobiography and journal, 1988, Library of Congress control number 88091258

See also

• Revolving door (politics)

External links

• Sustainability/Energy Savings/Stack pressures (MIT study)
• Revolving Door usage & sustainablity (MIT study)PDF (2.7 MB)
• Modernism/Modernity : Perpetual Revolution
• International Revolving Doors History

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