CTBUH Height Committee discusses the height criteria at the Trump Tower of Chicago (September 2009). Source: CTBUH.
The Council on Tall Buildings and Urban Habitat (CTBUH)—the international
body that arbitrates on tall building height and determines the title of “The
World’s Tallest Building”—has announced a change to its height criteria, as a
reflection of recent developments with several super-tall buildings.
The new criteria wording—“Height is measured from the level of the lowest,
significant, open-air, pedestrian entrance to…” allows for the recognition of
the increasing numbers of multi-use tall buildings with often several different
entrances at different levels, whilst also accommodating buildings constructed
in non-traditional urban or suburban locations. The CTBUH Height Committee has
determined that the previous description of where to measure tall building
height from—“Height is measured from the sidewalk outside the main entrance to…”
is now no longer sufficient.
This will have an impact on both the height of tall buildings and their
relative international height rankings. Burj Dubai, set to open as the world’s
tallest building in January 2010, will now be measured from the lowest of its
three main entrances (which opens into the entrance lobby for the tower’s
corporate suite office function), while the recently completed Trump
International Hotel & Towers in Chicago will be measured from the lower, publicly accessible Chicago Riverwalk. In the case of Trump, this additional 27 feet means that it will surpass the Jin Mao Tower in Shanghai to occupy the rank of 6th tallest on the current list of completed buildings.
“Beginning in 2007, with the knowledge that Burj Dubai would be significantly
taller than any structure ever built, the CTBUH Height Committee met to review
the criteria by which we recognize and rank the height of buildings,” said Peter
Weismantle, Chair of the CTBUH Height Committee and Director of Supertall
Building Technology at Adrian Smith + Gordon Gill Architecture in Chicago. “As
one might guess, with the committee being made up of architects, engineers,
contractors, developers, building owners and academics, a variety of opinions
and views were expressed. The resulting revisions almost two years later reflect
a general consensus of the committee in recognizing the most recent trends in
tall building development around the world.”
Also in response to the changing designs and forms of tall buildings, the
Height Committee has elected to discard its previous “Height to Roof” category.
“The roof category just doesn’t make sense anymore,” said CTBUH Executive
Director Antony Wood. “In the era of the flat-topped modernist tower, a clearly
defined roof could usually be identified, but in today’s tall building
world—which is increasingly adopting elaborate forms, spires, parapets and other
features at the top of the building—it is becoming difficult to determine a ‘roof’
at all, even less so to measure to it.”
The tallest 10 buildings in the world as of November 2009 are shown in the
diagrams below, ranked according to the three height categories now recognized
by CTBUH. These are: (i) Height to Architectural Top, measured to the topmost
architectural feature of the building including spires, but not including
antennae, signage, flag poles or other functional-technical equipment; (ii)
Height to Highest Occupied Floor, measured to the level of the highest,
consistently occupied floor in the building (thus not including service or
mechanical areas which experience occasional maintenance access); and (iii)
Height to Tip, measured to the highest point of the building, irrespective of
material or function of the highest element.
CTBUH Tall Building Height Categories
The CTBUH recognizes tall building height in three categories:
1. Height to Architectural Top: Height is measured from the level1 of the
lowest, significant2, open-air3, pedestrian4 entrance to the architectural top
of the building, including spires, but not including antennae, signage, flag
poles or other functional-technical equipment5. This measurement is the most
widely utilized and is employed to define the Council on Tall Buildings and
Urban Habitat (CTBUH) rankings of the Tallest Buildings in the World
World's tallest ten buildings according to Height fo Architectural Top as of November 2009. CTBUH
2. Highest Occupied Floor: Height is measured from the level1 of the lowest,
significant2, open-air3, pedestrian4 entrance to the highest occupied6 floor
within the building.
World's tallest ten buildings according to Heighest Occupied Floor as of November 2009. CTBUH
3. Height to Tip: Height is measured from the level1 of the lowest,
significant2, open-air3, pedestrian4 entrance to the highest point of the
building, irrespective of material or function of the highest element (i.e.
including antennae, flagpoles, signage and other functional-technical equipment).
World's tallest ten buildings according to Height to Tip as of November 2009. CTBUH
About the CTBUH
The Council on Tall Buildings and Urban Habitat, based at the Illinois Institute
of Technology in Chicago, is an international organization sponsored by
architecture, engineering, planning, and construction professionals, designed to
facilitate exchanges among those involved in all aspects of the planning,
design, construction and operation of tall buildings.
The CTBUH is the world’s leading body in the field of tall buildings, and the
recognized source of information on tall buildings internationally. It is the
arbiter of tall building height and determiner of the title of “The World’s
Tallest Building.” It maintains a significant database of built, under
construction and proposed tall buildings.
To download a PDF of the revised CTBUH Height Criteria, click
Criteria for the Defining and Measuring of Tall Buildings .
Further Information:
Council on Tall Buildings and Urban Habitat
eMail: info@ctbuh.org
web: www.ctbuh.org
Further Information on CTBUH height criteria:
Jan Klerks
Research & Communications Manager
Illinois Institute of Technology, S.R. Crown Hall
3360 South State Street, Chicago, IL 60616-3796, USA
Tel.: 1 (312) 567-3286
Fax: 1 (312) 567-3820
eMail: jklerks@ctbuh.org
web: criteria.ctbuh.org
Footnotes:
1 Level: finished floor level at threshold of the lowest entrance door
2 Significant: the entrance should be predominantly above existing or
pre-existing grade and permit access to one or more primary uses in the building
via elevators, as opposed to ground floor retail or other uses which solely
relate/connect to the immediately adjacent external environment. Thus entrances
via below-grade sunken plazas or similar are not generally recognized. Also note
that access to car park and/or ancillary/support areas are not considered
significant entrances.
3 Open-air: the entrance must be located directly off of an external space at
that level that is open to air.
4 Pedestrian: refers to common building users or occupants and is intended to
exclude service, ancillary, or similar areas.
5 Functional-technical equipment: this is intended to recognize that
