{"id":9807,"date":"2015-06-26T10:13:30","date_gmt":"2015-06-26T14:13:30","guid":{"rendered":"http:\/\/www.constructionspecifier.com\/?p=9807"},"modified":"2016-12-20T15:59:31","modified_gmt":"2016-12-20T20:59:31","slug":"the-ins-and-outs-of-revolving-doors","status":"publish","type":"post","link":"https:\/\/www.constructionspecifier.com\/the-ins-and-outs-of-revolving-doors\/","title":{"rendered":"The ins and outs of revolving doors"},"content":{"rendered":"
\"Figure<\/a>
All images courtesy Boon Edam<\/span><\/figcaption><\/figure>\n

by Glen Tracy
\n<\/strong>The built environment<\/a> is an energy-guzzler. The U.S. Green Building Council (USGBC) states in this country alone, buildings account for 41 percent of energy use, 73 percent of electricity consumption and 38 percent of all CO2 <\/sub>emissions, and 13.6 percent potable water consumption. Globally, buildings use 40 percent of raw materials, or about 3 billion tons annually. Fortunately, the type of doors we select can have a big impact on a building\u2019s energy profile.<\/p>\n

Revolving doors can be up to eight times more energy-efficient than their hinged counterparts\u2014all while allowing large numbers of people to pass in and out, boosting security, and adding architectural interest. In other words, not only can revolving doors efficiently handle bi-directional pedestrian traffic and reduce energy costs by maintaining an airlock, but they can also improve comfort for building occupants and offer more usable space at entrances compared to vestibules.<\/p>\n

This article discusses the green features of revolving doors and considers design elements as they relate to user comfort and safety. It also offers a checklist of must-dos in properly specifying a revolving door for a given project.<\/p>\n

ABCs of revolving doors
\n<\/strong>A revolving door generally consists of door wings that hang on a central shaft and rotate around a vertical axis within a cylindrical enclosure called a drum. There are usually two, three, or four wings that typically incorporate glass. The opening of the drum enclosure is referred to as the throat.<\/p>\n

Manual revolving doors rotate with push-bars, causing all wings to move. Large-diameter revolving doors use a motor to rotate automatically, and can accommodate strollers, wheelchairs, and wheeled luggage. A speed control (or \u2018governor\u2019) mounted in either the ceiling or floor prevents the door moving at an unsafe speed.<\/p>\n

Automatic revolving doors are powered above or below the central shaft, or along the perimeter. Sensors in the door wings and the enclosure frame ensure the speed with which the door revolves is limited. Other sensors can prevent or minimize the force of impact of the door wing on users.<\/p>\n

Revolving doors were invented in Philadelphia\u2028in 1888 by Theophilus Van Kannel to reduce air infiltration. His company\u2019s original motto was, \u201cAlways open, always closed\u201d\u2014that is, always open to people, always closed to the elements.<\/p>\n

A basic understanding of the way air behaves in a building sheds light on the benefits of revolving doors. Generally speaking, per the stack effect, air flows in and out of a building because of differences in air pressure and humidity. In the winter, heated air rises toward the top of a building and as long as there are any openings on the ground floor, cold air rushes in to replace the heated air. The opposite happens in the summer.<\/p>\n

Energy saved by revolving doors
\n<\/strong>In 2006, a team of graduate students at the Massachusetts Institute of Technology (MIT) conducted an analysis<\/a> of door use in one building on campus, where they found just 23 percent of visitors used the revolving doors. According to MIT\u2019s calculations, the swinging door allowed as much as eight times more air to pass through the building than the revolving door.<\/p>\n

According to the subsequent April 2009 MIT Tech<\/em> Talk publication:<\/p>\n

students indicated that if everyone were to use the revolving doors in this one building alone, MIT would save almost $7,500 in natural gas a year. That\u2019s enough to heat five houses over the same timeframe, and it also adds up to nearly 15 tons of CO2<\/sub>.<\/span><\/p>\n

The MIT findings on how revolving door usage affects energy consumption are shown in Figure 1.<\/p>\n

\"Figure<\/a>
Figure 1:<\/strong> Results from a Massachusetts Institute of Technology (MIT) study conducted by students to determine the energy savings of revolving doors compared to their traditional hinged counterparts.<\/span><\/figcaption><\/figure>\n

<\/p>\n

\"Figure<\/a>
The anatomy of a revolving door.<\/span><\/figcaption><\/figure>\n

Key elements of revolving door design
\n<\/strong>A building\u2019s entrance is its calling card\u2014its first contact with visitors\u2014and its design is a key element to its success. To specify the right revolving door for a given project, several factors must be considered.<\/p>\n

\"Figure<\/a>
Revolving doors have maintained an \u2018always open to people, always closed to the elements\u2019 approach since 1888.<\/span><\/figcaption><\/figure>\n

Fa\u00e7ade
\n<\/em>Revolving doors are an opportunity to enhance the drama of a building fa\u00e7ade. Today\u2019s all-glass fa\u00e7ades are the most popular building design and have virtually universal aesthetic appeal. Available in a wide variety of heights and widths with different canopy heights and heights under the canopy, an all-glass revolving door complements the appeal of a glass fa\u00e7ade.<\/p>\n

Minimal stainless steel trim and patch fittings contribute to a clean, sleek look. However, it is critical to note that all-glass revolving doors are typically manually operated in the USA. This is because automatic doors require safety sensors on the door wings per ANSI\/BHMA A156.27-2011, American National Standard for Power and Manual Operated <\/em>Revolving Pedestrian Doors<\/em>, and all-glass revolving door wings typically do not include the metal framing elements to mount the safety sensors.<\/p>\n

Connections to the building
\n<\/em>Revolving doors can be connected to buildings at the mid-post, throat opening, and in several \u2018keyhole\u2019 configurations including standard, double-bent glass, and angled. The common connection used is the mid-post. However, since half the door protrudes beyond the building envelope, it would not be recommended where pedestrian space is limited or without a protective building overhang. An interior keyhole may be used when the lobby is large enough that the door will not encroach on a nearby elevator lobby, stairs, and escalators.<\/p>\n

With an interior throat opening or keyhole connection, a door is completely mounted into the interior of a building and there is no part of the door itself exposed beyond the building envelope. This eliminates any rain or snow accumulating atop the door and greatly reduces accumulation inside the door. It also greatly benefits useful life and reduces the amount of maintenance needed. Finally, an interior mounted door creates a mini overhang or awning effect that protects users from rain or snow as they enter the door.<\/p>\n

Dimensional elements
\n<\/em>The diameter of the door, the width of vertical styles, and the height of the door opening, canopy, sidewall enclosure base, and bottom rail sideline can be optimized to create the desired look and complement surrounding building elements and doors. When these dimensional elements are specified with consideration of surrounding features, a fluid and harmonious sightline is created. For dramatic appeal, an additional curved glass enclosure can be constructed above the revolving door to elevate the door\u2019s visual impact.<\/p>\n

Security
\n<\/em>Security against human and natural hazards is a growing concern, and entry doors are a key focus. Most revolving door manufacturers offer various night locking options that can ensure the building is securely closed during non-opening hours. Options include different types of locking mechanisms that secure the door wings in their standard resting position, and night sliding doors that close over the throat opening of the revolving door.<\/p>\n

Doors can be locked from a remote location, and access control systems can be integrated with the door\u2028to allow authorized users to enter or exit the building. Along these lines, many employee-only entrances use security revolving doors to prevent \u2018tailgating\u2019 and \u2018piggybacking.\u2019 Vandal- and bullet-resistant glass is also available.<\/p>\n

Recommended surrounding features
\n<\/em>A popular strategy in colder sections of the country, building overhangs provide shelter from weather and keep snow and rain from getting inside the door. However, as described earlier, interior throat opening or keyhole connections can create the same benefit within the entry itself\u2014this makes for a simpler, cost-effective solution by requiring less of an exterior overhang to be built.<\/p>\n

Additionally, if access control is used, an overhang provides protection during the brief pause when\u2028a user must gain authorization before entering a security revolving door. Adequate attention should also be paid to flooring. Although there is no industry standard, most door manufacturers require the floor surface beneath the door\u2019s footprint to be perfectly dead level (or within a few millimeters) to ensure proper operation and correct weather seal along the bottom of the door wings.<\/p>\n

Using different flooring materials for the circular footprint of the revolving door itself visually signifies to users the actual path of the moving door wings and makes for less confusion and hesitation upon entering. The installation of the matting materials at the exterior and interior will help avoid slips and falls.<\/p>\n

Many buildings also employ stainless steel floor grates on either the exterior or interior side of the door or even under the entire door to collect dirt and debris before entry to decrease maintenance costs. Grating or matting that continues 3 m (10 ft) or more into the interior space can also help qualify for points under USGBC\u2019s rating program, Leadership in Energy and Environmental Design (LEED), working toward Indoor Environmental Quality (EQ) Credit 5, Indoor Chemical and Pollutant Source Control<\/em>.<\/p>\n

\"Figure<\/a><\/strong><\/p>\n

Capacity and type of use
\n<\/strong>While the above concerns are certainly important, the biggest issues in the specification of a revolving door are capacity and character of expected traffic. Architects will have to consider how many and what type of people are expected to enter and exit a facility. Will rush hours be a concern or will traffic be spread throughout the day? Will doors have to accommodate individuals with luggage or shopping carts? Capacity is based on type of facility and user demographic.<\/p>\n

Automatic doors<\/a> of any wing configuration, with large compartments, safety sensors and \u201cpush to slow\u201d buttons are generally applicable for facilities accommodating families, children, the elderly, or rolling baggage and carts, including museums, hospitals, airports, large retail establishments, and hotels and casinos. Small office buildings, restaurants, and specialty, high-end retail buildings are ideal for three- or four-wing manual revolving doors. Optimal capacity is reserved for \u2018trained traffic\u2019\u2014users familiar with the doors and the building who are either residents or employees who come and go on a regular basis.3<\/sup><\/p>\n

\"Figure<\/a>
An interior keyhole connection provides a mini-overhang to protect people and door from the elements.<\/span><\/figcaption><\/figure>\n

The various factors affecting capacity and user comfort include:<\/p>\n