Download What is a Tall Building?

Criteria for Defining and Measuring
Tall Buildings
CTBUH
How is the height of a tall building measured?
What is a Tall Building?
The CTBUH recognizes tall building height in four categories:
There is no hard, fast division on what constitutes a 'tall building'. It is a building that exhibits some element of
'tallness' in one or more of the following categories:
a) Height relative to context
It is not just about height, but about the urban situation in which it exists. Thus whereas a 12-story building may
not be considered a tall building in a high-rise city such as Chicago or Hong Kong, in a provincial European city
this may be distinctly taller than the urban norm.
1. Height to Architectural Top
b) Proportion
Again, a tall building is not just about height but about proportion. There are numerous buildings which are not
particularly high, but are slender enough to give the appearance of a tall building, especially against low urban
backgrounds. Conversely, there are numerous big / large footprint buildings which are quite tall but their size /
floor area rules them out as being classed as a tall building.
Height is measured from the sidewalk level outside the main entrance to the architectural top of the
building, including spires, but not including antennae, signage or flag poles. This measurement is
the most widely utilized and is used to define the rankings of the 100 Tallest Buildings in the World.
c) Tall Building Technologies
If a building contains technologies which may be attributed as being a product of 'tall' - e.g. specific vertical
transport technologies, structural wind bracing as a product of height, etc, then this building can be classed as a
tall building.
800m+/2600ft+ (est.)
Although number of floors is a poor indicator of defining a tall building due to the changing floor to floor height
between differing buildings and functions (e.g. office versus residential usage), a building of perhaps 14 or more
stories (or over 50 meters / 165 feet in height) could perhaps be used as a threshold for considering it a 'tall
building'.
509m/1670ft
450m/1476ft
452m/1483ft
1
Burj Dubai
Dubai
2009
What is a Super-Tall Building?
492m/1614ft
2
3
Shanghai World
Financial Center
Shanghai
2008
Taipei 101
Taipei
2004
4
5
442m/1451ft
440m/1444ft
6
Petronas Towers 1 & 2
Kuala Lumpur
1998
Nanjing Greenland
Financial Center
Nanjing
2009
421m/1381ft
415m/1362ft
Again, opinions on this differ internationally. Although great heights are now being achieved with built tall
buildings (in excess of 800 metres / 2600 feet), as of early 2010 there are expected to be only 50 buildings in
excess of 300 meters completed and occupied globally. The CTBUH thus defines ‘super-tall’ as being any building
over 300 metres / 984 feet in height.
7
8
9
10
Willis Tower
Chicago
1974
West Tower
Guangzhou
2009
Jin Mao Building
Shanghai
1999
Trump International
Hotel & Tower
Chicago
2009
What is the difference between a tall
building and a telecommunications /
observation tower?
A tall 'building' can be classed as such (as opposed to a telecommunications / observation tower) and is eligible
for the ‘Tallest’ lists if at least 50% of its height is occupied by usable floor area.
2. Highest Occupied Floor
Height is measured from the sidewalk level of the main entrance to the highest continually-occupied
floor within the building (i.e. not including maintenance areas).
< 50%
=
TELECOMMUNICATIONS
/ OBSERVATION TOWER
> 50%
=
BUILDING
Usable Floor Area
Oriental Pearl TV Tower
(Shanghai)
550+m/1800+ft (est.)
Jin Mao Tower
(Shanghai)
474m/1555ft
439m/1440ft
425m/1395ft
413m/1354ft
388m/1271ft
375m/1229ft
Building Status
373m/1224ft
348m/1143ft
When is a tall building considered to be ‘completed’?
A completed building can be considered such - and added to the 'tallest' lists - if it fulfils all three of the following
criteria:
1) topped out structurally and architecturally,
2) fully-clad,
3) open for business, or at least partially occupied
1
2
Burj Dubai
Dubai
2009
Shanghai World
Financial Center
Shanghai
2008
3
Taipei 101
Taipei
2004
4
5
6
7
West Tower
Guangzhou
2009
Willis Tower
Chicago
1974
Two International Finance
Centre
Hong Kong
2003
8
Petronas Towers 1 & 2
Kuala Lumpur
1998
9
10
Empire State Building
New York
1931
Jin Mao Building
Shanghai
1999
When is a tall building considered to be ‘topped out’?
A tall building is ‘topped out’ architecturally when it has reached its ultimate architectural height. e.g. including
spires, parapets, etc.
When is a tall building considered to be ‘under construction’?
A tall building is considered to be ‘under construction’ when site clearing has been completed and foundation /
piling work has begun.
When is a tall building considered to be ‘on-hold’?
A tall building is considered to be ‘on hold’ when it is widely reported within the public domain that construction
has halted
3. Height to Top of Roof
When is a tall building considered to be a ‘real’ proposal?
Height is measured from the sidewalk level of the main entrance to the highest point of the building’s
main roof level, not including spires or antennas.
A 'real' proposed tall building can be considered such if it fulfils all of the following criteria:
1) Has a specific site,
2) Has a developer / financier who owns the site,
3) Has a full professional design team who are in the process of progressing the design beyond the
conceptual stage,
4) Has a dialogue with the local planning authorities with a view to obtaining full legal permission for
construction,
5) Has a full intention to progress the building to construction and completion.
700+m/2250+ft (est.)
Only buildings that are fully in the public domain and fulfil all the above criteria will be included in the CTBUH
'proposed' building listings. Also, note that due to the changing nature of early stage designs and client
information restrictions, some height data for 'proposed' tall buildings that appears on the CTBUH 'Tallest Lists' is
unconfirmed.
492m/1614ft
449m/1473ft
442m/1451ft
432m/1417ft
392m/1285ft
383m/1255ft
381m/1250ft
379m/1242ft
Single-Function and Mixed Use Buildings
A single-function tall building is defined as one where 85% or more of its total floor area is dedicated to a single
usage.
1
2
Burj Dubai
Dubai
2009
Shanghai World
Financial Center
Shanghai
2008
3
Taipei 101
Taipei
2004
4
5
6
7
8
9 10
Willis Tower
Chicago
1974
West Tower
Guangzhou
2009
Two International
Finance Centre
Hong Kong
2003
Jin Mao Building
Shanghai
1999
Empire State Building
New York
1931
Petronas Towers 1 & 2
Kuala Lumpur
1998
4. Height to Tip
A mixed-use tall building contains two or more functions, where each of the functions occupy at least 15% of the
tower’s total floor area. Ancillary / support areas such as car parks and mechanical plant space do not constitute
mixed-use functions. Functions are denoted on CTBUH 'Tallest' lists in ascending order, e.g. ‘office / hotel’
indicates hotel function above office function.
SINGLE
FUNCTION
MIXED
USE
> 15%
> 85%
Height is measured from the sidewalk level of the main entrance to the highest point of the building,
irrespective of material or function of highest element (thus including antennae, flagpoles and
signage).
Retail
Office
> 15%
Residential
Parking
Observatory
800m+/2600ft+ (est.)
John Hancock Center
(Chicago)
Willis Tower
(Chicago)
Broadcast Equipment
/Antenna
Structural Material
527m/1729ft
509m/1670ft
A steel tall building is defined as one where the main vertical and lateral structural elements and floor systems
are constructed from steel. A concrete tall building is defined as one where the main vertical and lateral
structural elements and floor systems are constructed from concrete.
494m/1622ft
457m/1499ft
452m/1483ft
450m/1476ft
443m/1455ft
440m/1444ft
A composite tall building utilizes a combination of both steel and concrete acting compositely in the main
structural elements.
A mixed structure tall building is any building that utilizes distinct steel or concrete systems above or below each
other. There are two main types of mixed structural system: A concrete/steel tall building indicates a steel
structural system located above a concrete structural system, with the opposite true of a steel/concrete building.
1
Burj Dubai
Dubai
2009
2
Willis Tower
Chicago
1974
3
Taipei 101
Taipei
2004
4
5
Shanghai World
Financial Center
Shanghai
2008
John Hancock Center
Chicago
1969
6
7
Petronas Towers 1 & 2
Kuala Lumpur
1998
Note: The diagrams above represent the Ten Tallest Buildings in the World in each category as they are projected to be by early 2010.
8
9
10
Nanjing Greenland
Financial Center
Nanjing
2009
Empire State Building
New York
1931
West Tower
Guangzhou
2009
Additional Notes:
1. If a tall building is of steel construction with a floor system of concrete planks on steel beams, it's considered a
steel tall building.
2. If a tall building is of steel construction with a floor system of a concrete slab on steel beams, it's considered a
steel tall building.
3. If a tall building has steel columns plus a floor system of concrete beams, it's considered a composite tall
building.