Council on Tall Buildings and Urban Habitat
From Free net encyclopedia
The Council on Tall buildings and Urban Habitat (CTBUH) was founded at Lehigh University in 1969. Its office remained at Lehigh until October 2003, when it moved to the Illinois Institute of Technology in Chicago, Illinois. Although its stated mission is to study and report "on all aspects of the planning, design, and construction of tall buildings", it is best known to the general public for its compilation and ranking of the World's 100 Tallest Buildings.
The ranking of tall buildings was originally based on a building's height from the sidewalk level of the main entrance to the architectural top of the building. The "architectural top" included towers, spires (but not antennas), masts or flagpoles. In 1996, as Petronas Twin Towers was nearing completion, CTBUH expanded its system to rank the tallest buildings in three additional categories -- the highest occupied floor, the top of the roof, and the top of the pinnacle (the heighest point in the structure of the building). These categories are listed and defined below:
- Pinnacle Height/Spire Height: the height from the sidewalk level of the building to the architectural top of the tower. This vague definition can lead to confusion, but basically any structure beyond occupiable floors that is architecturally significant in its design and structurally integrated into its height is considered a spire. A spire and an antenna can sometimes coincide, as in the new design for Freedom Tower, but generally they do not.
- Heighest Occupied Floor: the height from sidewalk level to the level of the heighest occupied floor.
- Roof Height: the height from sidewalk level to the roof of the building. In many cases buildings terminate with a spire or decorative feature of some sort that is not occupied, in the case of Roof Height, buildings with unoccupied spires are measured in this category by the height from sidewalk level to the top of the ceiling of the heighest occupied level.
- Pinnacle Height: the height from sidewalk level to the top of the structure of the building. This height may include antennas.
In 2005 the CTBUH partnered with Emporis to develop a much larger database of high-rise buildings with height data and expanded categories of technical data. The Emporis and CTBUH building databases have been integrated, and have always used the same standards for measurement of tall buildings.
See also
External links
