An Australian company has described the epic task of cleaning the windows of the world's biggest skyscraper in Dubai, using squeegees, buckets and 3 million US dollars of high-tech equipment.
Dale Harding, general manager of Cox Gomyl, said the firm designed and installed the Burj Khalifa's unique window-cleaning carousels which were in action ahead of its official opening this week.
Twelve machines weighing 13 tonnes carry up to 36 cleaners, who use ordinary soapy water to wash down the Burj's 24,830 reflective windows in a process that takes three months, top to bottom.
"It's the same as an average shop front cleaner would use - there's nothing complex about it at all," he told AFP Tuesday.
The cleaners stand on the specially designed machines, which emerge from cavities in the skyscraper and track along rails skirting its curved towers.
He said the company had been working overtime to get the 828-metre (2,717-foot) building gleaming for Monday's extravagant opening ceremony.
"It's an enormous challenge. The architects had some fairly high expectations," Harding said.
"It's an iconic building with high exposure. They wanted it as clean as possible, particularly for the opening. There have been some fairly tight deadlines over the past few months."
He said the Burj, which towers over the Dubai desert, has 120,000 square metres of glass (1,292,500 square feet) and 45,000 square metres of aluminium and stainless steel panels.
"It's an incredible construction. People are focusing on the height of the building but the sheer size of it, the footprint, is huge. It's really 10-15 conventional buildings," Harding said.