Photo © Adam Mørk
Finally, if applicable, review the leaf projection of the door to the exterior to prevent it from protruding onto the sidewalk area and possibly obstructing pedestrian traffic. While traditional doors have a circular arc projection, the elliptical swing path of a balanced door reduces door leaf projection by one-third. In many cities, sidewalk space is valuable. If there is heavy foot traffic, a door opening into the flow of traffic can interrupt passersby. Only two-thirds of a balanced door leaf project to the exterior of the building. Many cities, such as New York City, have stringent door projection codes—the balanced door’s reduced leaf projection is especially useful in these situations.
Performance to code compliance
When choosing an appropriate entrance system, it is very critical to follow the American with Disabilities Act (ADA) to not only avoid legal ramifications, but also ensure easy access for everyone. The most updated version of the regulation, the 2010 revised requirements (with a compliance date on or after March 15, 2012), is consistent with the International Building Code (IBC) guidelines.
Among the most pertinent guidelines associated with entry systems is ADA 404.2.3, “Clear Width,” and involves clear opening space. It reads:
Door openings shall provide a clear width of 815 mm [32 in.] minimum. Clear openings of doorways with swinging doors shall be measured between the face of the door and the stop, with the door open 90 degrees. Openings more than 610 mm [24 in.] deep shall provide a clear opening of 915 mm [36 in.] minimum. There shall be no projections into the required clear opening width lower than 865 mm [34 in.] above the finish floor or ground. Projections into
the clear opening width between 865 mm and 2030 mm [80 in.] above the finish floor or ground shall not exceed 100 mm [4 in.].
When considering balanced door manufacturers, it is important to choose one with extensive knowledge about ADA guidelines to ensure the proper measurements are taken into account. For a single door, it is typically possible to meet the 815 mm minimum width requirement, provided the leaf is at least 940 mm (37 in.) with a 1092 mm (43 in.) total frame width. This allows the 102 mm (4 in.) required for balanced hardware, the approximately 25 mm (1 in.) required for door stop material on the opposing side, and the 76-mm (3-in.) door jambs at each side. A pair of doors with a 1981-mm (78-in.) frame (914 mm [36 in.] per door) would also provide an 815-mm opening with one door fully open, bringing in similar opening dimensions to a swing or pivot door.
A second pertinent consideration for ADA responsibility is opening force requirement. The Act does not have guidelines for opening force for exterior doors because it would be too inhibiting. Exterior doors are often large and heavy, and also have panic or latching devices, which must function properly. ADA does not limit the use of such devices with a strict guideline, but does pose an advisory in section 404.2.9, “Door and Gate Opening Force,” which reads:
The maximum force pertains to the continuous application of force necessary to fully open a door, not the initial force needed to overcome the inertia of the door. It does not apply to the force required to retract bolts or to disengage other devices used to keep the door in a closed position.
Although ADA does not universally require power operation functionality on entry systems, some cities (e.g. Chicago) need at least one power-operated entry on every new public building. Therefore, it is important to choose a balanced door manufacturer with the ability to make power-operated balanced doors. If power operation is desired, it must be a low-energy, power-operated door complying with the American National Standards Institute (ANSI) A 156.19, Power-assist and Low-energy Power-operated Doors.
Beauty
Since its invention in 1927, balanced door assemblies have graced the entrances of well-known museums, libraries, government facilities, flagship retail entrances, and corporate headquarters. From the Art Institute of Chicago and the Smithsonian buildings in Washington, D.C., to World Trade Center and the Empire State Building, balanced doors have been specified for high-profile projects because of their sheer craftsmanship and beauty.
