Big Buildings - Dirty Secrets

The CTBUH uses the term "vanity spires" to describe tops of buildings where a ton of extra height is added, even though that space isn't used for people.

The List: how big buildings are cleaned - How big buildings are cleaned – from the Burj Khalifa in Dubai to the Empire State Building in New York. This week, a specialist team ascended London’s Houses of Parliament to clean the clock faces of the Elizabeth Tower – home to the famous Big Ben bell. The hands on each of the clock’s four faces were frozen for the week-long task but its chimes still rang out and the workers on the 96m-tall tower wore ear defenders to protect their hearing. Kasia Delgado reveals how four other big buildings around the world are cleaned.

1. Burj Khalifa, Dubai

The 24,830 windows of the world’s tallest building are made from a million sq ft of glass. When the 830m tower was cleaned in 2012 a team of 36 people needed three months to wash them. They started from the top floor and worked down, standing on specially designed machines that emerged from cavities in the skyscraper and moved along rails skirting its curved towers. The project manager at Grako, the cleaning company that took on the task, said that coping with the height was “all about mindset”.

2. Empire State Building, New York

Window-washers at the 6,500-window Manhattan landmark have reported how, in winter, food and drink thrown out of windows of high-up floors often freezes on glass lower down – and that frozen coffee and yoghurt, for example, can be particularly difficult to scrub off. This is, of course, far from the only problem when cleaning a New York skyscraper. Richard Hart, head of the Empire State window-washing team in 1937, remarked casually that, “I’ll be working away, and a gust of wind will come screaming up from 34th Street and for a moment I’ll be doing a tap dance on nothing. Anyway, it keeps me interested.”

3. Petronas Towers, Malaysia

When the Petronas Towers were opened in Kuala Lumpur in 1996 there was a dispute over whether they were taller than the Sears building in Chicago (now called the Willis Tower) – the world’s tallest when it was completed in 1973. What is not in doubt is the cleanliness of the skyscrapers’ glass. The two towers are fitted with a total of 11 cranes that allow cleaners to move up and down between the 32,000 windows. It takes workers a month to clean the panes on each tower and, when they finish, they go back to the top and begin again.

4. Hearst Tower, New York

It took engineers three years to build a machine that would enable cleaners to wash Norman Foster’s 182m tall skyscraper, which opened in 2006. The windows, made up of concave diamond shapes, were impossible to access using ordinary means so a rectangular steel box the size of a small car was designed to move around the roof of the tower on an elevated steel track. The project’s construction manager described the car as “like a ride at Disneyland”.

The 10 Tallest Vanity Spires - click to enlarge.

The World's Tallest Skyscrapers Have A Dirty Little Secret - The Burj Khalifa in Dubai and the Bank of America tower in New York count among the worst offenders: Supertall skyscrapers aren't necessarily built to fit as many people inside as possible, sometimes they're just aiming to be, well, really tall. Large portions of these buildings are designed to increase height, but remain unoccupied. Wasteful!

The Council on Tall Buildings and Urban Habitat (CTBUH), a not for profit organization that tracks the world's skyscrapers, just released some data on that subject. Surprise! Some really tall buildings don't need to be so tall. The CTBUH uses the term "vanity spires" to describe tops of buildings where a ton of extra height is added, even though that space isn't used for people. By unused height, above are the 10 buildings with the most ridiculous spires (click to enlarge picture).

So the Burj Khalifa, the tallest building in the World at nearly 830 meters, has 244 meters of unoccupied space. To put that in context, as the CTBUH does, if that 244 meters were itself a building, it would be the 11th tallest in Europe. Pretty crazy, right? But it's also not new. Think about classic skyscrapers like the Empire State Building and the Chrysler Building, which were similarly designed with big spires. You might notice that the skyscrapers with the largest vanity spires were all built fairly recently (the oldest is from 1999) but there are also just more supertall buildings being erected. It would take a little more math to say buildings like this are on the rise, so to speak.

It's also not clear how these spires change the buildings' environmental footprints, although we know at least one of them listed above, the Bank of America Tower in New York, has some pretty serious efficiency issues. One of the study's authors, CTBUH's Daniel Safarik, wrote in an email to PopularScience that "we did not explicitly look at how vanity height affects environmental footprint for this study, but that is clearly one of the most vital issues implied by the findings." Just having the title of "tallest" is a draw for a building, he says, it matters less what all that space is used for. So what to do? "If [a tallest building] criteria were based on 'highest occupied floor,' in theory, there would be less of an incentive to have the 'vanity height,'" Safarik writes.

Until that changes, more buildings may add vanity height just to top other structures. Or maybe we can keep things the way they are, and just have a skyscraper where you can't go above the lobby.

So the Burj Khalifa, the tallest building in the world at nearly 830 meters, has 244 meters of unoccupied space. To put that in context, as the CTBUH does, if that 244 meters were itself a building, it would be the 11th tallest in Europe. Here, meanwhile, are those buildings broken down geographically. Click to enlarge.