The building’s parapet rises to a height of 1,368 feet, the same height as the original World Trade Center Tower 1. It is topped by a 408-foot needle that was completed in May. The CTBUH, which certifies building heights and record-setting buildings, decided that the needle was a spire, “a vertical element that completes the architectural expression of the building and is intended as permanent.” The organization counts spires as structural elements, but not antennas, signs, or flagpoles.
Chief architect David Childs, of Skidmore, Owings & Merrill, originally intended for the needle to be enclosed in a radome, an architectural structure constructed of fiberglass and steel. However, that idea was scrapped because the radome would not have been able to be serviced or maintained.
The building’s 104 floors and three million square feet of interior space will be home to offices, restaurants, and retailers. An observation deck will allow the public to enjoy an impressive view of the New York skyline.
One World Trade Center’s sustainable design incorporates renewable energy, interior daylighting, reuse of rainwater, and recycled construction materials and debris. It will be connected to New York’s impressive public transportation network.
Given the building’s height, its engineers had to design creative ways to transport people efficiently. Thyssen Krupp designed the world’s fastest and most advanced elevator system for the project, with 73 elevators and 11 escalators.
One World Trade Center’s developers expect 14,000 people per day, over five million per year, to visit the observation deck. Ten elevators will travel directly from the ground floor to the top in one minute.
Over 10,000 people are expected to work in offices throughout the building. Engineers have developed a “Destination Dispatch” system that will know where people work based on the identification cards they present when going through security. It will use an intranet to group passengers together based on their destinations and tell them which elevator to take to get to their offices as quickly as possible. People working above the 64th floor will take an express elevator to the sky lobby and then another elevator to their offices.
Safety was an important consideration for the building’s designers. The engineers who designed the elevator system took into consideration lessons learned on September 11, 2001. The building has a stronger core than its predecessor. In the past, in the event of a fire, an elevator would stop below the affected floor, and firefighters would have to get out and climb the stairs to battle the blaze. The new elevators will have a second door that opens into a second corridor. The building also incorporates structural redundancy, fireproofing, biochemical filters, extra-wide pressurized stairs, multiple backups for emergency lighting, concrete protection for sprinklers, exits designed for easy evacuation, and safety systems encased in the core wall.
Once it is completed next year, One World Trade Center will be the world’s third-tallest building, after only the Burj Khalifa in Dubai and Makkah Royal Clock in Mecca, Saudi Arabia.