Council on Tall Buildings and Urban Habitat
CTBUH Height Committee Meeting

View the CTBUH's current Criteria for Defining and Measuring Tall Buildings and the CTBUH Tallest Database

The world of tall building design has changed much in the past decade, with non-orthogonal and iconic, sculptural forms for tall buildings being increasingly proposed. It is timely to discuss and debate the criteria on which tall building height is measured – and thus also the ‘world’s tallest’ determined – since the criteria established in the mid-1990’s may no longer be relevant. Certainly the distinctions between ‘spire’ and ‘antennae’ in the classifications seem less distinct in many of today’s proposals, and there are varying situations at the ground plane (e.g. ‘artificial’ berms?) and with elements such as parapets and roof-mounted features. Should the highest occupied floor now take more dominance in determining the world’s tallest building?

The Council on Tall Buildings and Urban Habitat, the historic arbitrator of tall building height criteria, together with the College of Architecture at Illinois Institute of Technology thus called for all interested CTBUH organizational members to send one representative to an international meeting in Chicago to discuss / debate the issues and perhaps redefine the criteria for the next decade or more. This meeting took place on Thursday 24th May 2007 at the Illinois Institute of Technology.

Agenda for the Meeting:
The meeting considered the following key issues:

• How can you distinguish between an architectural spire and a communications ‘antennae’, and what should be included in determining the height of a building?

• Where should the ‘base’ of a building be considered for measurement, with today’s raised earth-berms, elevated roadways, riverfront access etc?

• What is the difference between a telecommunications ‘tower’ and a tall ‘building’, and how do you classify the several shades of variation in between?

• Should a consideration of building mass, form and highest occupied floor have a role in determining the world’s highest?

• Should rooftop features, e.g. chimneys, water towers, wind turbines, signage etc contribute to the building height?