page_title: One World Trade Center
section_title: Specifications and operations
hierarchical_section_title: One World Trade Center / Original building (1971–2001) / Specifications and operations
caption_attribution_description: English: A photo of the World Trade Center lobby taken on 19 August, 2000. Digitally altered with Photoshop 7 to remove a small but distracting white chain across the lobby and to desaturate the ceiling lights to remove a purple tint.
context_page_description: One World Trade Center is the main building of the rebuilt World Trade Center complex in Lower Manhattan, New York City. One WTC is the tallest building in the United States, the tallest building in the Western Hemisphere, and the seventh-tallest in the world. The supertall structure has the same name as the North Tower of the original World Trade Center, which was destroyed in the terrorist attacks of September 11, 2001. The new skyscraper stands on the northwest corner of the 16-acre World Trade Center site, on the site of the original 6 World Trade Center. The building is bounded by West Street to the west, Vesey Street to the north, Fulton Street to the south, and Washington Street to the east.
  The building's architect is David Childs, whose firm Skidmore, Owings & Merrill also designed the Burj Khalifa and the Willis Tower. The construction of below-ground utility relocations, footings, and foundations for the new building began on April 27, 2006. One World Trade Center became the tallest structure in New York City on April 30, 2012, when it surpassed the height of the Empire State Building. The tower's steel structure was topped out on August 30, 2012.
context_section_description: After Seven World Trade Center was built in the 1980s, the World Trade Center complex had a total of seven buildings; however, the most notable ones were the main Twin Towers built in the 1970s—One World Trade Center was the North Tower, and Two World Trade Center was the South Tower. Each tower was over 1,350 feet (410 m) high, and occupied about 1 acre (0.40 ha) of the total 16 acres (6.5 ha) of the site's land. During a press conference in 1973, Yamasaki was asked, "Why two 110-story buildings? Why not one 220-story building?" His response was, "I didn't want to lose the human scale."
  When it was topped out on October, 1971, One World Trade Center became the tallest building in the world, surpassing the Empire State Building, which had held the record for 40 years. The North Tower was 1,368 feet (417 m) tall, and in 1978, a telecommunications antenna was added to the top of the roof; by itself, the antenna was 360 feet (110 m) tall. With the 360-foot (110 m)-tall antenna, the highest point of the North Tower reached 1,728 ft (527 m). However, the tower only held its record until May 1973, when Chicago's Sears Tower (now Willis Tower), which was 1,450 feet (440 m) tall at the rooftop, was completed. At 110 floors, the World Trade Center towers had more floors than any other building at that time. This number was not surpassed until the construction of the Burj Khalifa (163 floors), which opened in 2010.
  Of the 110 stories, 8 were set aside as mechanical floors (floors 7/8, 41/42, 75/76, and 108/109), which were 4 two-floor areas that were spaced up the building in even intervals. All the remaining floors were open for tenants. Each floor of the tower had 40,000 square feet (3,700 m²) of available space. The North and South tower had 3,800,000 square feet (350,000 m²) of total office space. The entire complex of seven buildings had a combined total of 13,400,000 square feet (1,240,000 m²) of office space.
  The complex initially failed to attract the expected clientele. During the early years, various governmental organizations became key tenants of the World Trade Center, such as the State of New York. In the 1980s, the city's perilous financial condition eased, after which an increasing number of private companies—mostly financial firms related to Wall Street—became tenants. During the 1990s, approximately 500 companies had offices in the complex, including financial companies such as Morgan Stanley, Aon Corporation, and Salomon Brothers. The basement concourse of the World Trade Center included The Mall at the World Trade Center, and a PATH station. The North Tower became the main corporate headquarters of Cantor Fitzgerald, and it also became the headquarters of the Port Authority of New York and New Jersey.
  The tower's electrical service was supplied by Consolidated Edison (ConEd) at 13,800 volts. The electricity passed through the World Trade Center Primary Distribution Center (PDC), and was then sent up the building's core to electrical substations located on the mechanical floors. The substations lowered the 13,800 primary voltage to 480/277 volts, and the voltage was then further lowered to 208/120 volts for general power and lighting services. The complex was also served by emergency generators located in the sub-levels of the towers and on the roof of Five World Trade Center.
  The 110th floor of One World Trade Center (the North Tower) housed radio and television transmission equipment. The roof of the North Tower contained a vast array of transmission antennas, including the 360 feet (110 m) center antenna mast, rebuilt by Dielectric Inc. to support DTV in 1999. The center mast contained the television signals for almost all NYC television broadcasters: WCBS-TV 2, WNBC-TV 4, WNYW 5, WABC-TV 7, WWOR-TV 9 Secaucus, WPIX 11, WNET 13 Newark, WPXN-TV 31 and WNJU 47 Linden. It also had four NYC FM broadcasters: WPAT-FM 93.1, WNYC 93.9, WKCR 89.9, and WKTU 103.5. Access to the roof was controlled by the WTC Operations Control Center (OCC), located in the B1 level of the South Tower. After the September 11 attacks of 2
caption: Lobby of Tower 1, looking south along the east side of the building, August 19, 2000
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