and other space. Throughout the late 20th century, the original layout of the offices was changed. The partitions originally reached from the floor to the ceiling, but they were replaced with half-height partitions in 2010, when each story was converted into an open plan space. Floor 17 contained an interpreters' lounge and the UN's art and cartography divisions, while floor 20 contained an in-house barber shop. Floor 38 contained offices and an apartment for the Secretary-General of the United Nations. In addition, floor 38 contained a private switchboard and an office for the President of the United Nations General Assembly; most Secretariat employees were not allowed to visit this story. The offices are divided into modules measuring wide, with movable partitions that align with the mullions on the facade. Originally, the offices included French desks as well as aluminum chairs. Some of the original furnishings were restored in 2010, while others were replaced with replicas. The building uses over of acoustic ceiling tiles. Each ceiling contains lighting fixtures spaced at regular intervals, which are outfitted with egg-crate louvers to reduce glare. The ceilings slope up near each window. Each office had a set of Venetian blinds, allowing occupants to adjust natural light levels as necessary; there were 2,200 Venetian blinds in total. The New York Times reported that the building contained of partitions, of electrical wiring, 11,000 electrical outlets, and of pipes. The Secretariat Building contained an air-conditioning system with 4,000 individual sets of controls. This system not only reduced cooling costs by at least 25 percent, but also allowed delegates and staff to customize the temperatures of their own offices. Offices within of a window are cooled by high-velocity air conditioning units underneath the windows. For offices near the center of the building, cool air is delivered through low-velocity units in the ceilings. The cool air was provided by a pair of centrifugal compressors, which could collectively generate 2,300 tons of air. There are hot-water heating units beneath the windows, within the north and south walls of the building, and underneath the floor slab of the first story; in addition, there are steam heaters in the pipe galleries. The dehumidifiers on each story are supplied by chilled water from the East River at a rate of more than per minute. The use of East River water precluded the need for a dedicated cooling tower, which would have required increasing