With such an enormous tower to maintain and almost countless pieces of windows to keep spotless clean, it is such a wonder as to how windows could be cleaned. However, the issue of washing windows was most probably dealt with beforehand; even before the construction of the grand tower began.
To wash the 24,348 windows, totaling 120,000 m2 (1,290,000 sq ft) of glass, a horizontal track has been installed on the exterior of Burj Khalifa at levels 40, 73, and 109. Each track holds a 1,500 kg (3,300 lb) bucket machine which moves horizontally and then vertically using heavy cables. Above level 109, up to tier 27 traditional cradles from davits are used. The top of the spire, however, is reserved for specialist window cleaners, who brave the heights and high winds dangling by ropes to clean and inspect the top of the pinnacle.
Under normal conditions, when all building maintenance units will be operational, it will take 36 workers three to four months to clean the entire exterior façade. Unmanned machines will clean the top 27 additional tiers and the glass spire. Whew!
The cleaning system which is state-of-the-art machines was developed in Melbourne, Australia at a cost of A$ 8 million, by an Australian company , Cox Gomyl.