Making criteria robust

There was a need to tighten the criteria for tall buildings, says Antony Wood, CTBUH Executive Director. (SUPPLIED)

This year, the Council on Tall Buildings and Urban Habitat (CTBUH) will set up a new working committee for wind engineering. In a telephone interview, Emirates Business spoke to Antony Wood, Executive Director, CTBUH, who cleared up the air on the sudden change in height criteria for tall buildings and the history behind the decision.


When did you start the process to change the criteria for tall buildings?

AThe CTBUH has the remit to arbitrate on heights of tall buildings and has had a Height Committee for the past 20 years. Its first real work was in the mid-90s, with the issue between the Sears Towers and the Petronas Towers. In May 2007, the group was reconvened in Chicago and that is when we took this decision to debate and change the whole height criteria. The attention is always at the top of the tower and on spires and antennae. But the base of the tower has also been an increasingly contentious issue, because our criteria – as it has been worded – not robust enough for many of the tall buildings that we see today, such as the Burj Dubai.

So what do you do when the building has multiple entrances?

APrior to the change, the criteria used to say that height should be measured from the level of the sidewalk outside the main entrance. But of course, if you have a building that has more than one main entrance – which is increasingly the case – then that does not make sense. Therefore, we changed the criteria to say that height is measured from the level of the lowest open air pedestrian entrance. The Burj Dubai has three entrances and we measured from the lowest one, which is the hotel. We have taken the opportunity to introduce the word "open air" (see page 25) because buildings have entrances from underground car parks and that should not be counted in the height of the building. Basically, the idea was to tighten the criteria.

How many members are in the Heights Committee?

ASome 36 members. Peter Weismantle is the Chair of the CTBUH Height Committee and Director of Supertall Building Technology at Adrian Smith + Gordon Gill Architecture in Chicago.

Will having someone from the architect's office affect the objectivity of this criteria?

ANo. There are some 36 people in the project. Though the chairman on the committee was formerly with Som, this was not an exercise in making the Burj Dubai taller. We don't need to do that. The Burj Dubai is so much taller than any other building, a few more metres would not make any difference. The aim was to make the criteria more robust. But the council will never allow any one to influence such decisions. What we have done is not controversial; it is sensible.

The Burj Dubai also has an entrance from the Dubai Mall, which goes straight into the Burj Dubai observatory. Will you take this as an entrance?

ANo, we are not looking at measuring the height from the mall. The tower has three functions – residential, hotel and office. We will measure the height from the entrance lobby of the corporate suite offices, which is slightly lower than the Dubai Mall. That is not going to change. When the High Committee looked at the drawings, the observatory entrance was never mentioned.

When will you take this decision?

AThat will happen when we get the drawings and inspect them.

So do you have the height?

ANo. We have the drawings without the measurements on them. It is all about the client feeling comfortable to issue the height of the building, then we can ratify the height. Until then, we cannot announce anything.

Is the office entrance considerably lower than the other two levels?

AYes, it is a few metres lower than the other entrances.

What are the plans for the CTBUH in 2010?

AWe have a conference in February. We've also launched our new division on regional research on tall buildings. Our traditional role has been as a disseminator, but we want to be involved in original research. We have launched a new database on tall buildings on our website, which will be a free service, features more than 10,000 tall buildings and helping you create your own lists.

So far, the Council on Tall Buildings and Urban Habitat has working groups on sustainability, fire and safety, seismic design, progressive collapse, awards committee, the Height Committee, legal aspects of tall buildings, finance and economic and construction logistics.

This year, the organisation will set up a new committee on wind engineering and harnessing wind energy.

 

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