A revolving door in Turkey (counter-clockwise rotation)
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. To use a revolving door, a person enters the enclosure between two of the doors and then moves continuously to the desired exit while keeping pace with the doors.
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 allowing large numbers of people to pass in and out. They are also energy efficient; they act as an airlock to prevent drafts, decreasing the loss of heating or cooling for the building as compared to a standard door.[1]
Construction
Diagram of a revolving door, viewed from above
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 pushchairs and wheeled luggage racks - such large capacity doors are sometimes H-shaped to split the circle into only two (hence larger) parts.
Some revolving door displays incorporate a small glass enclosure, permitting small objects such as sculpture, fashion mannequins, 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) 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.[2]
Skyscraper design requires a means of draft block, such as 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 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 three or four 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,[3] revolving doors revolve clockwise,[4] but door rotations are mixed in Britain.[5] Direction of rotation is often enforced by the door governor mechanism, or by the orientation of the door seal brush (weatherstrips).
Security
An unusual pair of revolving doors at City Hall in London: one revolves clockwise; the other revolves counterclockwise.
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. 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 that person to exit, while also notifying security of the attempt.
A one-way High Entrance/Exit Turnstile
Turnstile exit-only doors are also often used in subways and other rapid transit facilities to prevent people from bypassing fare payment. They are similarly used at large sports stadiums, amusement parks, 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
On November 28, 1942, the Cocoanut Grove, a popular nightclub in Boston, Massachusetts, 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, 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 OntarioBuilding 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".[6]
History
Patent drawing by Theophilus Van Kannel for a "Storm-Door Structure", 1888Large revolving door with a central display case (counter-clockwise rotation). Revolving door is flanked on both sides by conventional doors with arrows pointing inward towards the preferred entry.
H. Bockhacker of Berlin was granted German patent DE18349[7] 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".[8] 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 [sic] 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.[9]
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, there is no evidence to support this.[10]
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,[14][15] who worked for the van Kannel revolving door company at the time. Simpson's study was followed by a study by Schutrum et al.[16] in 1961, and more recently a study by van Schijndel et al.[17] in 2003. These studies 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. However, none of these studies are referenced by existing design codes.[citation needed]
The aforementioned studies are specific to the type of door which they were acquired for, namely 2m ×2m (6.6ft ×6.6ft) doors with four compartments.[18] Although it appears that these dimensions were standard for four-compartment doors at the time, this is not the case nowadays.[citation needed] A more recent experimental study[19][20][21] carried out at Imperial College London's Department of Civil and Environmental Engineering, 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.[22] and by Schutrum et al.[16] 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.[23] 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.[24]
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 by controlling access to the doorway (portal). Conventionally, it is a panel that fits into the doorway of a building, room, or vehicle. Doors are generally made of a material suited to the door's task. They are commonly attached by hinges, but can move by other means, such as slides or counterbalancing.
A window is an opening in a wall, door, roof, or vehicle that allows the exchange of light and may also allow the passage of sound and sometimes air. Modern windows are usually glazed or covered in some other transparent or translucent material, a sash set in a frame in the opening; the sash and frame are also referred to as a window. Many glazed windows may be opened, to allow ventilation, or closed to exclude inclement weather. Windows may have a latch or similar mechanism to lock the window shut or to hold it open by various amounts.
Heating, ventilation, and air conditioning (HVAC) is the use of various technologies to control the temperature, humidity, and purity of the air in an enclosed space. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer. "Refrigeration" is sometimes added to the field's abbreviation as HVAC&R or HVACR, or "ventilation" is dropped, as in HACR.
Ventilation is the intentional introduction of outdoor air into a space. Ventilation is mainly used to control indoor air quality by diluting and displacing indoor pollutants; it can also be used to control indoor temperature, humidity, and air motion to benefit thermal comfort, satisfaction with other aspects of the indoor environment, or other objectives.
A blower door is a machine used to perform a building air leakage test. It can also be used to measure airflow between building zones, to test ductwork airtightness and to help physically locate air leakage sites in the building envelope.
A fire escape is a special kind of emergency exit, usually mounted to the outside of a building—occasionally inside, but separate from the main areas of the building. It provides a method of escape in the event of a fire or other emergency that makes the stairwells inside a building inaccessible. Fire escapes are most often found on multiple-story residential buildings, such as apartment buildings.
An air door or air curtain is a device used to prevent air, contaminants, or flying insects from moving from one open space to another. The most common implementation is a downward-facing blower fan mounted over an entrance to a building, or over an opening between two spaces conditioned at different temperatures.
A building envelope or building enclosure is the physical separator between the conditioned and unconditioned environment of a building, including the resistance to air, water, heat, light, and noise transfer.
Building insulation is material used in a building to reduce the flow of thermal energy. While the majority of insulation in buildings is for thermal purposes, the term also applies to acoustic insulation, fire insulation, and impact insulation. Often an insulation material will be chosen for its ability to perform several of these functions at once.
Passive ventilation is the process of supplying air to and removing air from an indoor space without using mechanical systems. It refers to the flow of external air to an indoor space as a result of pressure differences arising from natural forces.
Infiltration is the unintentional or accidental introduction of outside air into a building, typically through cracks in the building envelope and through use of doors for passage. Infiltration is sometimes called air leakage. The leakage of room air out of a building, intentionally or not, is called exfiltration. Infiltration is caused by wind, negative pressurization of the building, and by air buoyancy forces known commonly as the stack effect.
A thermal bridge, also called a cold bridge, heat bridge, or thermal bypass, is an area or component of an object which has higher thermal conductivity than the surrounding materials, creating a path of least resistance for heat transfer. Thermal bridges result in an overall reduction in thermal resistance of the object. The term is frequently discussed in the context of a building's thermal envelope where thermal bridges result in heat transfer into or out of conditioned space.
An energy audit is an inspection survey and an analysis of energy flows for energy conservation in a building. It may include a process or system to reduce the amount of energy input into the system without negatively affecting the output. In commercial and industrial real estate, an energy audit is the first step in identifying opportunities to reduce energy expense and carbon footprint.
Air changes per hour, abbreviated ACPH or ACH, or air change rate is the number of times that the total air volume in a room or space is completely removed and replaced in an hour. If the air in the space is either uniform or perfectly mixed, air changes per hour is a measure of how many times the air within a defined space is replaced each hour. Perfectly mixed air refers to a theoretical condition where supply air is instantly and uniformly mixed with the air already present in a space, so that conditions such as age of air and concentration of pollutants are spatially uniform.
Underfloor air distribution (UFAD) is an air distribution strategy for providing ventilation and space conditioning in buildings as part of the design of a HVAC system. UFAD systems use an underfloor supply plenum located between the structural concrete slab and a raised floor system to supply conditioned air to supply outlets, located at or near floor level within the occupied space. Air returns from the room at ceiling level or the maximum allowable height above the occupied zone.
A dedicated outdoor air system (DOAS) is a type of heating, ventilation and air-conditioning (HVAC) system that consists of two parallel systems: a dedicated system for delivering outdoor air ventilation that handles both the latent and sensible loads of conditioning the ventilation air, and a parallel system to handle the loads generated by indoor/process sources and those that pass through the building enclosure.
ANSI/ASHRAE/IES Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings is an American National Standards Institute (ANSI) standard published by ASHRAE and jointly sponsored by the Illuminating Engineering Society (IES) that provides minimum requirements for energy efficient designs for buildings except for low-rise residential buildings. The original standard, ASHRAE 90, was published in 1975. There have been multiple editions to it since. In 1999 the ASHRAE Board of Directors voted to place the standard on continuous maintenance, based on rapid changes in energy technology and energy prices. This allows it to be updated multiple times in a year. The standard was renamed ASHRAE 90.1 in 2001. It has since been updated in 2004, 2007, 2010, 2013, 2016, and 2019 to reflect newer and more efficient technologies.
Radiant heating and cooling is a category of HVAC technologies that exchange heat by both convection and radiation with the environments they are designed to heat or cool. There are many subcategories of radiant heating and cooling, including: "radiant ceiling panels", "embedded surface systems", "thermally active building systems", and infrared heaters. According to some definitions, a technology is only included in this category if radiation comprises more than 50% of its heat exchange with the environment; therefore technologies such as radiators and chilled beams are usually not considered radiant heating or cooling. Within this category, it is practical to distinguish between high temperature radiant heating, and radiant heating or cooling with more moderate source temperatures. This article mainly addresses radiant heating and cooling with moderate source temperatures, used to heat or cool indoor environments. Moderate temperature radiant heating and cooling is usually composed of relatively large surfaces that are internally heated or cooled using hydronic or electrical sources. For high temperature indoor or outdoor radiant heating, see: Infrared heater. For snow melt applications see: Snowmelt system.
Building airtightness can be defined as the resistance to inward or outward air leakage through unintentional leakage points or areas in the building envelope. This air leakage is driven by differential pressures across the building envelope due to the combined effects of stack, external wind and mechanical ventilation systems.
Ductwork airtightness can be defined as the resistance to inward or outward air leakage through the ductwork envelope. This air leakage is driven by differential pressures across the ductwork envelope due to the combined effects of stack and fan operation.
↑ The city in slang: New York life and popular speech. Irving Lewis Allen. Publisher: New York; Oxford University Press, 1993. Page 126. ISBN0-19-509265-1
↑ Simpson, A. M. and Atkinson, K. B. InfInfiltration Problem of Multiple Entrances. Heating, piping and air conditioning, vol. 8 no. 6 pp 345 - 351, 1936
↑ Simpson, A. M. Infiltration Characteristics of Entrance Doors. Journal of refrigerating engineering, vol. 31 no. 6 pp 345 -350, 1936
1 2 Schutrum, L. F., Ozisik, N., Baker, J. T. and Humphreys, C. M. Air Infiltrations through Revolving Doors, ASHRAE transactions, vol. 3 no. 1 pp. 43 - 50, 1961
↑ Van Schijndel, H., Zmeureanu, R., Stathopoulos, T. Simulation of Air Infiltration through Revolving Doors, Proceedings of Building simulations 2003 conference, pp. 1193 - 2000, 2003
↑ Beardmore, A. The Revolving Door Since 1881: Architecture in Detail, Boon Edam P.V., 2000
↑ Allgayer, D. M. and Hunt, G. R., Air Movement by Revolving Doors, Proceedings of the RoomVent 2004 conference, 2004
↑ Allgayer, D. M. and Hunt, G. R., Hybrid Ventilation by Revolving Doors, Proceedings of the HealthyBuildings 2006 conference, vol. 4 pp. 215 - 220, 2006
↑ Allgayer, D. M. Air and Heat Movement by Revolving Doors, PhD Thesis, Imperial College London, 2006 {dead link, Sept 2024}
↑ Zmeureanu, R., Stathopoulos, T., Schopmeijer, M. E. D. Air Leakage Through the Building Envelope via Revolving Doors, Proceedings of the International conference on building envelopes, systems and technology, pp. 467 - 472, 2001
↑ ASHRAE ASHRAE/IESNA Standard 90.1-1999: Energy Standard for Buildings Except Low-Rise Residential Buildings, US, 1999
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