7 World Trade Center
Encyclopedia
7 World Trade Center is a building in New York City
New York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...

 located across from the World Trade Center site
World Trade Center site
The World Trade Center site , also known as "Ground Zero" after the September 11 attacks, sits on in Lower Manhattan in New York City...

 in Lower Manhattan
Lower Manhattan
Lower Manhattan is the southernmost part of the island of Manhattan, the main island and center of business and government of the City of New York...

. It is the second building to bear that name and address in that location. The original structure was completed in 1987 and was destroyed in the September 11 attacks. The current 7 World Trade Center opened in 2006 on part of the site of the old 7 World Trade Center. Both buildings were developed by Larry Silverstein
Larry Silverstein
Larry A. Silverstein is an American businessman, and real estate investor and developer in New York City.Silverstein was born in Brooklyn, and became involved in real estate, together with his father, establishing Silverstein Properties...

, who holds a ground lease
Ground rent
Ground rent, sometimes known as a rentcharge, is a regular payment required under a lease from the owner of leasehold property, payable to the freeholder. A ground rent is created when a freehold piece of land or a building is sold on a long lease...

 for the site from the Port Authority of New York and New Jersey
Port Authority of New York and New Jersey
The Port Authority of New York and New Jersey is a bi-state port district, established in 1921 through an interstate compact, that runs most of the regional transportation infrastructure, including the bridges, tunnels, airports, and seaports, within the Port of New York and New Jersey...

.

The original 7 World Trade Center was 47 stories tall, clad in red exterior masonry, and occupied a trapezoid
Trapezoid
In Euclidean geometry, a convex quadrilateral with one pair of parallel sides is referred to as a trapezoid in American English and as a trapezium in English outside North America. A trapezoid with vertices ABCD is denoted...

al footprint. An elevated walkway connected the building to the World Trade Center
World Trade Center
The original World Trade Center was a complex with seven buildings featuring landmark twin towers in Lower Manhattan, New York City, United States. The complex opened on April 4, 1973, and was destroyed in 2001 during the September 11 attacks. The site is currently being rebuilt with five new...

 plaza. The building was situated above a Consolidated Edison
Consolidated Edison
Consolidated Edison, Inc. is one of the largest investor-owned energy companies in the United States, with approximately $14 billion in annual revenues and $36 billion in assets...

 (Con Ed) power substation, which imposed unique structural design constraints. When the building opened in 1987, Silverstein had difficulties attracting tenants. In 1988, Salomon Brothers
Salomon Brothers
Salomon Brothers was a bulge bracket, Wall Street investment bank. Founded in 1910 by three brothers along with a clerk named Ben Levy, it remained a partnership until the early 1980s, when it was acquired by the commodity trading firm Phibro Corporation and then became Salomon Inc. Eventually...

 signed a long-term lease, and became the main tenants of the building. On September 11, 2001, 7 WTC was damaged by debris when the nearby North Tower of the WTC collapsed
Collapse of the World Trade Center
The twin towers of the World Trade Center collapsed on September 11, 2001, as a result of al-Qaeda's September 11 attacks, in which terrorists affiliated with al-Qaeda hijacked four commercial passenger jet airliners, flying one into the North Tower and another into the South Tower...

. The debris also ignited fires, which continued to burn throughout the afternoon on lower floors of the building. The building's internal fire suppression system lacked water pressure to fight the fires, and the building collapsed completely at 5:21:10 pm.

Construction of the new 7 World Trade Center began in 2002 and was completed in 2006. It is 52 stories tall, making it the 29th tallest building in New York, and is still situated above the Con Ed power substation. Built on a smaller footprint than the original to allow Greenwich Street to be restored from TriBeCa
TriBeCa
Tribeca is a neighborhood in Lower Manhattan, New York in the United States. Its name is an acronym based on the words "Triangle below Canal Street", and is properly bounded by Canal Street, West Street, Broadway, and Vesey Street...

 through the World Trade Center site and south to Battery Park
Battery Park
Battery Park is a 25-acre public park located at the Battery, the southern tip of Manhattan Island in New York City, facing New York Harbor. The Battery is named for artillery batteries that were positioned there in the city's early years in order to protect the settlement behind them...

, the new building is bounded by Greenwich
Greenwich Street (Manhattan)
Greenwich Street is a north-south street in the New York City borough of Manhattan. It extends from the intersection of Ninth Avenue and Gansevoort Street in the Meatpacking District at its northernmost end to its southern end at Battery Park, interrupted between Vesey and Liberty Streets by the...

, Vesey
Vesey Street (Manhattan)
Vesey Street is a street in New York City that runs east-west in Lower Manhattan. The street is named after Rev. William Vesey , the first rector of nearby Trinity Church....

, Washington
Washington Street (Manhattan)
Washington Street is a north-south street in the New York City borough of Manhattan. Running from 14th Street in the Meatpacking District at its northernmost end to its southern end at Hubert Street in TriBeCa, Washington Street is, for its entire length, the westernmost street in lower Manhattan...

, and Barclay streets. A small park across Greenwich Street was created in a space that was part of the original building's footprint. The current 7 World Trade Center is designed to emphasize safety, with a reinforced concrete
Reinforced concrete
Reinforced concrete is concrete in which reinforcement bars , reinforcement grids, plates or fibers have been incorporated to strengthen the concrete in tension. It was invented by French gardener Joseph Monier in 1849 and patented in 1867. The term Ferro Concrete refers only to concrete that is...

 core, wider stairways, and thicker fireproofing of steel columns. It also incorporates numerous green design features. The building was the first commercial office building in New York City to receive the U.S. Green Building Council's Leadership in Energy and Environmental Design
Leadership in Energy and Environmental Design
Leadership in Energy and Environmental Design consists of a suite of rating systems for the design, construction and operation of high performance green buildings, homes and neighborhoods....

 (LEED) certification, where it won a gold rating and was one of the first projects accepted to be part of the Council's Pilot Program for Leadership in Energy and Environmental Design – Core and Shell Development (LEED-CS).

The first 7 World Trade Center (1983–2001)

The original 7 World Trade Center was a 47-story building, designed by Emery Roth & Sons
Emery Roth
Emery Roth was an American architect who designed many of the definitive New York City hotels and apartment buildings of the 1920s and 30s, incorporating Beaux-Arts and Art Deco details...

, with a red granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...

 facade. The building was 610 feet (185.9 m) tall, with a trapezoid
Trapezoid
In Euclidean geometry, a convex quadrilateral with one pair of parallel sides is referred to as a trapezoid in American English and as a trapezium in English outside North America. A trapezoid with vertices ABCD is denoted...

al footprint that was 330 ft (100.6 m) long and 140 ft (42.7 m) wide. Tishman Realty & Construction
Tishman Realty & Construction
Tishman Realty & Construction is an American corporation that owns and operates Tishman Construction Corporation and Tishman Hotel & Realty.-Tishman Construction Corporation:...

 managed construction of the building, which began in 1983. In March 1987, the building opened, becoming the seventh structure of the World Trade Center
World Trade Center
The original World Trade Center was a complex with seven buildings featuring landmark twin towers in Lower Manhattan, New York City, United States. The complex opened on April 4, 1973, and was destroyed in 2001 during the September 11 attacks. The site is currently being rebuilt with five new...

.

The building was constructed above a Con Edison
Consolidated Edison
Consolidated Edison, Inc. is one of the largest investor-owned energy companies in the United States, with approximately $14 billion in annual revenues and $36 billion in assets...

 substation
Electrical substation
A substation is a part of an electrical generation, transmission, and distribution system. Substations transform voltage from high to low, or the reverse, or perform any of several other important functions...

 that had been on the site since 1967. The substation had a caisson
Caisson (engineering)
In geotechnical engineering, a caisson is a retaining, watertight structure used, for example, to work on the foundations of a bridge pier, for the construction of a concrete dam, or for the repair of ships. These are constructed such that the water can be pumped out, keeping the working...

 foundation designed to carry the weight of a future building of 25 stories containing 600000 sq ft (55,741.8 m²). The final design for 7 World Trade Center was for a much larger building covering a larger footprint than originally planned when the substation was built.

The structural design of 7 World Trade Center included features to allow a larger building than originally planned to be constructed. A system of gravity column transfer trusses and girders was located between floors 5 and 7 to transfer loads to the smaller foundation. Existing caissons installed in 1967 were used, along with new ones, to accommodate the building. The fifth floor functioned as a structural diaphragm, providing lateral stability and distribution of loads between the new and old caissons. Above the seventh floor, the building's structure was a typical tube-frame design, with columns in the core and on the perimeter, and lateral loads resisted by perimeter moment frames.
A shipping and receiving ramp, which served the entire World Trade Center complex, occupied the eastern quarter of the 7 World Trade Center footprint. The building was open below the third floor, providing space for truck clearance on the shipping ramp. The spray-on fireproofing
Fireproofing
Fireproofing, a passive fire protection measure, refers to the act of making materials or structures more resistant to fire, or to those materials themselves, or the act of applying such materials. Applying a certification listed fireproofing system to certain structures allows these to have a...

 for structural steel elements was gypsum
Gypsum
Gypsum is a very soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is found in alabaster, a decorative stone used in Ancient Egypt. It is the second softest mineral on the Mohs Hardness Scale...

-based Monokote
Monokote
MonoKote is commercially available light weight plastic shrink wrap film available in various color schemes with an adhesive on one side, used to cover and form the surfaces of a model aircraft. The material is cut to size and applied to the airframe surfaces using a hobby iron or heat gun...

 which had a two-hour fire rating for steel beams, girders and truss, and a three-hour rating for columns.

Mechanical equipment was installed on floors four through seven, including 12 transformer
Transformer
A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field...

s on the fifth floor. Several generators in the building were used by the Office of Emergency Management, Salomon Smith Barney and others. Storage tanks contained 24,000 gallons (91,000 L) of diesel fuel to supply the generators. Fuel oil distribution components were located at ground level, up to the ninth floor. After the World Trade Center bombings of February 26, 1993, New York City mayor Rudy Giuliani decided to situate the emergency command center and associated fuel tanks at 7 World Trade Center. Although this decision was criticized in light of the events of 9/11, the fuel in the building is today not believed to have contributed to the collapse of the building. The roof of the building included a small west penthouse and a larger east mechanical penthouse.

Each floor had 47000 sq ft (4,366.4 m²) of rentable office space which made the building's floor plans considerably larger than most office buildings in the City.
In all, 7 World Trade Center had 1868000 sq ft (173,542.9 m²) of office space. Two pedestrian bridges connected the main World Trade Center complex, across Vesey Street, to the third floor of 7 World Trade Center. The lobby of 7 World Trade Center had three murals by artist Al Held
Al Held
Al Held was an American Abstract expressionist painter. He was particularly well known for his large scale Hard-edge paintings.-Background and education:...

: The Third Circle, Pan North XII, and Vorces VII.

Tenants

In June 1986, before construction was completed, Silverstein signed Drexel Burnham Lambert
Drexel Burnham Lambert
Drexel Burnham Lambert was a major Wall Street investment banking firm, which first rose to prominence and then was forced into bankruptcy in February 1990 by its involvement in illegal activities in the junk bond market, driven by Drexel employee Michael Milken. At its height, it was the...

 as a tenant to lease the entire 7 World Trade Center building for $3 billion over a term of 30 years.
In December 1986, after the Boesky
Ivan Boesky
Ivan Frederick Boesky is an American stock trader who is notable for his prominent role in a Wall Street insider trading scandal that occurred in the United States in the mid-1980s.-Life and career:...

 insider-trading
Insider trading
Insider trading is the trading of a corporation's stock or other securities by individuals with potential access to non-public information about the company...

 scandal, Drexel Burnham Lambert canceled the lease, leaving Silverstein to find other tenants.
Spicer & Oppenheim agreed to lease 14 percent of the space, but for more than a year, as Black Monday
Black Monday (1987)
In finance, Black Monday refers to Monday October 19, 1987, when stock markets around the world crashed, shedding a huge value in a very short time. The crash began in Hong Kong and spread west to Europe, hitting the United States after other markets had already declined by a significant margin...

 and other factors adversely affected the Lower Manhattan
Lower Manhattan
Lower Manhattan is the southernmost part of the island of Manhattan, the main island and center of business and government of the City of New York...

 real estate market, Silverstein was unable to find tenants for the remaining space. By April 1988, Silverstein had lowered the rent and made other concessions.

In November 1988, Salomon Brothers
Salomon Brothers
Salomon Brothers was a bulge bracket, Wall Street investment bank. Founded in 1910 by three brothers along with a clerk named Ben Levy, it remained a partnership until the early 1980s, when it was acquired by the commodity trading firm Phibro Corporation and then became Salomon Inc. Eventually...

 withdrew from plans to build a large new complex at Columbus Circle
Columbus Circle
Columbus Circle, named for Christopher Columbus, is a major landmark and point of attraction in the New York City borough of Manhattan, located at the intersection of Eighth Avenue, Broadway, Central Park South , and Central Park West, at the southwest corner of Central Park. It is the point from...

 in Midtown
Midtown Manhattan
Midtown Manhattan, or simply Midtown, is an area of Manhattan, New York City home to world-famous commercial zones such as Rockefeller Center, Broadway, and Times Square...

 and agreed to a 20-year lease for the top 19 floors of 7 World Trade Center.
The building was extensively renovated in 1989 to accommodate the needs of Salomon Brothers.
Most of three existing floors were removed as tenants continued to occupy other floors, and more than 350 tons (U.S.) of steel were added to construct three double-height trading floors. Nine diesel generators were installed on the 5th floor as part of a backup power station. "Essentially, Salomon is constructing a building within a building – and it's an occupied building, which complicates the situation," said a district manager of Silverstein Properties. The unusual task was possible, said Larry Silverstein
Larry Silverstein
Larry A. Silverstein is an American businessman, and real estate investor and developer in New York City.Silverstein was born in Brooklyn, and became involved in real estate, together with his father, establishing Silverstein Properties...

, because it was designed to allow for "entire portions of floors to be removed without affecting the building's structural integrity, on the assumption that someone might need double-height floors."

At the time of the September 11, 2001 attacks, Salomon Smith Barney was by far the largest tenant in 7 World Trade Center, occupying 1202900 sq ft (111,753.1 m²) (64 percent of the building) which included floors 28–45. Other major tenants included ITT Hartford Insurance Group
The Hartford
The Hartford Financial Services Group, Inc. , usually known as The Hartford, is a Fortune 500 company and one of America’s largest investment and insurance companies...

 (122,590 sq ft/11,400 m²), American Express
American Express
American Express Company or AmEx, is an American multinational financial services corporation headquartered in Three World Financial Center, Manhattan, New York City, New York, United States. Founded in 1850, it is one of the 30 components of the Dow Jones Industrial Average. The company is best...

 Bank International (106,117 sq ft/9,900 m²), Standard Chartered Bank
Standard Chartered Bank
Standard Chartered PLC is a multinational financial services company headquartered in London, United Kingdom with operations in more than seventy countries...

 (111,398 sq ft/10,350 m²), and the Securities and Exchange Commission (106,117 sq ft/9,850 m²). Smaller tenants included the Internal Revenue Service
Internal Revenue Service
The Internal Revenue Service is the revenue service of the United States federal government. The agency is a bureau of the Department of the Treasury, and is under the immediate direction of the Commissioner of Internal Revenue...

 Regional Council (90,430 sq ft/8,400 m²) and the United States Secret Service
United States Secret Service
The United States Secret Service is a United States federal law enforcement agency that is part of the United States Department of Homeland Security. The sworn members are divided among the Special Agents and the Uniformed Division. Until March 1, 2003, the Service was part of the United States...

 (85,343 sq ft/7,900 m²). The smallest tenants included the New York City Office of Emergency Management, National Association of Insurance Commissioners
National Association of Insurance Commissioners
The National Association of Insurance Commissioners is an Internal Revenue Code Section 501 non-profit organization which seeks to organize the regulatory and supervisory efforts of the various state insurance commissioners from around the United States. The NAIC was formed in 1871. Its current...

, Federal Home Loan Bank, First State Management Group Inc., Provident Financial Management
PNC Financial Services
PNC Financial Services Group, Inc. is a U.S.-based financial services corporation, with assets of approximately $264.3 billion...

, and the Immigration and Naturalization Service. The Department of Defense
United States Department of Defense
The United States Department of Defense is the U.S...

 (DOD) and Central Intelligence Agency
Central Intelligence Agency
The Central Intelligence Agency is a civilian intelligence agency of the United States government. It is an executive agency and reports directly to the Director of National Intelligence, responsible for providing national security intelligence assessment to senior United States policymakers...

 (CIA) shared the 25th floor with the IRS. Floors 46–47 were mechanical floors, as were the bottom six floors and part of the seventh floor.

9/11 and collapse

As the North Tower collapsed on September 11, 2001, heavy debris hit 7 World Trade Center damaging the south face of the building and starting fires that continued to burn throughout the afternoon. The collapse also caused damage to the southwest corner with other possible damage including a large vertical gash near the center of the south face. The building was equipped with a sprinkler system, but had many single-point vulnerabilities for failure: the sprinkler system required manual initiation of the electrical fire pumps, rather than being a fully automatic system; the floor-level controls had a single connection to the sprinkler water riser; and the sprinkler system required some power for the fire pump
Fire pump
A fire pump is a part of a fire sprinkler system's water supply and can be powered by electric, diesel or steam. The pump intake is either connected to the public underground water supply piping, or a static water source . The pump provides water flow at a higher pressure to the sprinkler system...

 to deliver water. Also, water pressure was low, with little or no water to feed sprinklers.

After the North Tower collapsed, some firefighters entered 7 World Trade Center to search the building. They attempted to extinguish small pockets of fire, but low water pressure hindered their efforts. Over the course of the day fires burned out of control on several floors of the 7 World Trade Center. At approximately 2:00 pm, firefighters noticed a bulge in the southwest corner of 7 World Trade Center between the 10th and 13th floors, a sign that the building was unstable and might collapse. During the afternoon, firefighters also heard creaking sounds coming from the building. Around 3:30 pm FDNY Chief Daniel Nigro decided to halt rescue operations, surface removal, and searches along the surface of the debris near 7 World Trade Center and evacuate the area due to concerns for the safety of personnel. At 5:20:33 pm EDT the building started to collapse, with the crumble of the east mechanical penthouse, and at 5:21:10 pm EDT 7 World Trade Center collapsed completely. There were no casualties
Casualty (person)
A casualty is a person who is the victim of an accident, injury, or trauma. The word casualties is most often used by the news media to describe deaths and injuries resulting from wars or disasters...

 associated with the collapse.

In May 2002, the Federal Emergency Management Agency
Federal Emergency Management Agency
The Federal Emergency Management Agency is an agency of the United States Department of Homeland Security, initially created by Presidential Reorganization Plan No. 1 of 1978 and implemented by two Executive Orders...

 (FEMA) issued a report on the collapse based on a preliminary investigation conducted jointly with the Structural Engineering Institute of the American Society of Civil Engineers
American Society of Civil Engineers
The American Society of Civil Engineers is a professional body founded in 1852 to represent members of the civil engineering profession worldwide. It is the oldest national engineering society in the United States. ASCE's vision is to have engineers positioned as global leaders who strive toward...

 under leadership of Dr. W. Gene Corley
W. Gene Corley
Dr. W. Gene Corley, P.E. is an American structural engineer and "preeminent expert on building collapse investigations and building codes." Corley has been the Senior Vice President of CTLGroup since 1987, where he leads structural engineering projects, including numerous evaluations of buildings...

, P.E. FEMA made preliminary findings that the collapse was not primarily caused by actual impact damage from the collapse of 1 WTC and 2 WTC but by fires on multiple stories ignited by debris from the other two towers that continued unabated due to lack of water for sprinklers or manual firefighting. The report did not reach conclusions about the cause of the collapse and called for further investigation.

Responding to FEMA's concerns, the National Institute of Standards and Technology
National Institute of Standards and Technology
The National Institute of Standards and Technology , known between 1901 and 1988 as the National Bureau of Standards , is a measurement standards laboratory, otherwise known as a National Metrological Institute , which is a non-regulatory agency of the United States Department of Commerce...

 (NIST) was authorized to lead an investigation into the structural failure and collapse of the World Trade Center twin towers and 7 World Trade Center. The investigation, led by Dr S. Shyam Sunder, drew upon in-house technical expertise as well as the knowledge of several outside private institutions, including the Structural Engineering Institute of the American Society of Civil Engineers
American Society of Civil Engineers
The American Society of Civil Engineers is a professional body founded in 1852 to represent members of the civil engineering profession worldwide. It is the oldest national engineering society in the United States. ASCE's vision is to have engineers positioned as global leaders who strive toward...

 (SEI/ASCE), the Society of Fire Protection Engineers
Society of Fire Protection Engineers
The Society of Fire Protection Engineers is a professional society for fire protection engineering established in 1950. SFPE publishes the Journal of Fire Protection Engineering, published on behalf of the society by SAGE Publications and Fire Protection Engineering magazine is published...

 (SFPE), the National Fire Protection Association
National Fire Protection Association
The National Fire Protection Association is a United States trade association that creates and maintains private, copywrited, standards and codes for usage and adoption by local governments...

 (NFPA), the American Institute of Steel Construction (AISC), the Council on Tall Buildings and Urban Habitat
Council on Tall Buildings and Urban Habitat
The Council on Tall Buildings and Urban Habitat is an international body in the field of tall buildings and sustainable urban design...

 (CTBUH), and the Structural Engineers Association of New York
National Council of Structural Engineers Associations
The National Council of Structural Engineers Associations is a professional society in the United States, with subchapters in 45 states and the District of Columbia. NCSEA was established in 1993, in Chicago...

 (SEAoNY).

NIST's investigation of the building's collapse was delayed until after reports were completed on the collapse of the World Trade Center
Collapse of the World Trade Center
The twin towers of the World Trade Center collapsed on September 11, 2001, as a result of al-Qaeda's September 11 attacks, in which terrorists affiliated with al-Qaeda hijacked four commercial passenger jet airliners, flying one into the North Tower and another into the South Tower...

 twin towers. In the meantime, NIST provided a preliminary report about 7 World Trade Center in June 2004, and thereafter released occasional updates on the investigation. According to NIST, the investigation of 7 World Trade Center was delayed for a number of reasons, including that NIST staff who had been working on 7 World Trade Center were assigned full-time from June 2004 to September 2005 to work on the investigation of the collapse of the twin towers. In June 2007, Shyam Sunder explained, "We are proceeding as quickly as possible while rigorously testing and evaluating a wide range of scenarios to reach the most definitive conclusion possible. The 7 WTC investigation is in some respects just as challenging, if not more so, than the study of the towers. However, the current study does benefit greatly from the significant technological advances achieved and lessons learned from our work on the towers."

In November 2008, NIST released its final report on the causes of the collapse of 7 World Trade Center. This followed their August 21, 2008 draft report which included a period for public comments. In its investigation, NIST utilized ANSYS to model events leading up to collapse initiation and LS-DYNA
LS-DYNA
LS-DYNA is an advanced general-purpose multiphysics simulation software package developed by the Livermore Software Technology Corporation...

 models to simulate the global response to the initiating events. NIST determined that diesel fuel did not play an important role, nor did the structural damage from the collapse of the twin towers, nor did the transfer elements (trusses, girders, and cantilever overhangs). But the lack of water to fight the fire was an important factor. The fires burned out of control during the afternoon, causing floor beams near Column 79 to expand and push a key girder off its seat, triggering the floors to fail around column 79 on Floors 8 to 14. With a loss of lateral support across nine floors, Column 79 soon buckled – pulling the East penthouse and nearby columns down with it. With the buckling of these critical columns, the collapse then progressed east-to-west across the core, ultimately overloading the perimeter support, which buckled between Floors 7 and 17, causing the entire building above to fall downward as a single unit. The fires, fueled by office contents, along with the lack of water, were the key reasons for the collapse.

When the first 7 World Trade Center collapsed, debris caused substantial damage and contamination to the Borough of Manhattan Community College
Borough of Manhattan Community College
The Borough of Manhattan Community College is one of six two-year colleges within the City University of New York system and the only one in Manhattan. Founded in 1963, BMCC originally offered business-oriented and liberal arts degrees for those intending to enter the business world or transfer...

's Fiterman Hall building, located adjacent at 30 West Broadway, to the extent that the building was not salvageable. The adjacent Verizon Building
Verizon Building
The Verizon Building is a 32-story Art Deco building in New York City, located in Lower Manhattan. It is named for Verizon Communications, for which it is the headquarters. The building is located at 140 West Street, adjacent to the World Trade Center site and 7 World Trade Center, and is bounded...

, an art deco
Art Deco
Art deco , or deco, is an eclectic artistic and design style that began in Paris in the 1920s and flourished internationally throughout the 1930s, into the World War II era. The style influenced all areas of design, including architecture and interior design, industrial design, fashion and...

 building constructed in 1926, had extensive damage to its east facade from the collapse of 7 World Trade Center, though it was able to be restored at a cost of US$1.4 billion.

7 World Trade Center housed SEC files relating to numerous Wall Street investigations, as well as other federal investigative files. All the files for approximately 3,000 to 4,000 SEC cases were destroyed. Although some were backed up elsewhere, others were not, especially those classified as confidential. Files relating to Citigroup's connection to the WorldCom scandal were lost. The Equal Employment Opportunity Commission estimated over 10,000 cases were affected. Investigative files in the Secret Service's largest field office, with more than 200 employees, were also lost in the collapse of WTC 7. One Secret Service agent said, “All the evidence that we stored at 7 World Trade, in all our cases, went down with the building.”

The NIST report found no evidence supporting conspiracy theories that 7 World Trade Center was brought down by controlled demolition. Specifically, the window breakage pattern and blast sounds that would have resulted from the use of explosives were not observed. The suggestion that an incendiary material such as thermite
Thermite
Thermite is a pyrotechnic composition of a metal powder and a metal oxide that produces an exothermic oxidation-reduction reaction known as a thermite reaction. If aluminium is the reducing agent it is called an aluminothermic reaction...

 was used instead of explosives was considered unlikely by NIST because of observations of the fire and the building's structural response to the fire, and because it is unlikely the required quantity of material could have been planted without discovery.

The old 7 World Trade Center was the first tall building known to have collapsed primarily due to uncontrolled fires. Based on its investigation, NIST reiterated several recommendations it had made in its earlier report on the collapse of the twin towers, and urged immediate action on a further recommendation: that fire resistance should be evaluated under the assumption that sprinklers are unavailable; and that the effects of thermal expansion on floor support systems be considered. Recognizing that current building codes are drawn to prevent loss of life rather than building collapse, the main point of NIST's recommendations was that buildings should not collapse from fire even if sprinklers are unavailable.

The second 7 World Trade Center (2002 - Present)

The new 7 World Trade Center has 52 stories and is 741 ft (225.9 m) tall. The building has 42 floors of leasable space, starting at the 11th floor, and a total of 1700000 sq ft (157,935.2 m²) of office space. The first ten floors house an electrical substation, which provides power to much of Lower Manhattan. The office tower has a narrower footprint at ground level than its predecessor so the course of Greenwich Street could be restored to reunite TriBeCa
TriBeCa
Tribeca is a neighborhood in Lower Manhattan, New York in the United States. Its name is an acronym based on the words "Triangle below Canal Street", and is properly bounded by Canal Street, West Street, Broadway, and Vesey Street...

 and the Financial District.

Design

David Childs
David Childs
David M. Childs is the Consulting Design Partner at Skidmore, Owings and Merrill. He is best known for his redesign of the new One World Trade Center in New York....

 of Skidmore, Owings and Merrill
Skidmore, Owings and Merrill
Skidmore, Owings and Merrill LLP is an American architectural and engineering firm that was formed in Chicago in 1936 by Louis Skidmore and Nathaniel Owings; in 1939 they were joined by John O. Merrill. They opened their first branch in New York City, New York in 1937. SOM is one of the largest...

 worked in conjunction with glass artist and designer James Carpenter to create a design that uses ultra-clear, low-iron glass to provide reflectivity and light, with stainless-steel spandrels behind the glass to help reflect sunlight. Stainless steel used in the building façade is molybdenum
Molybdenum
Molybdenum , is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores...

-containing Type 316, which provides improved resistance to corrosion. To enclose the power substation and improve its aesthetics, the base of the building has a curtain wall with stainless steel
Stainless steel
In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....

 louver
Louver
A louver or louvre , from the French l'ouvert; "the open one") is a window, blind or shutter with horizontal slats that are angled to admit light and air, but to keep out rain, direct sunshine, and noise...

s that provide ventilation for the machinery. During the day, the curtain wall reflects light, while at night it is illuminated with blue LED
Light-emitting diode
A light-emitting diode is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting...

 lights. The curtain wall around the lobby uses heavily laminated, heat-strengthened glass that meets high standards for blast resistance. At night, a large cube of light above the lobby also emanates blue light, while during the day it provides white light to the lobby, and at dusk it transitions to violet and back to blue. Inside the main lobby, artist Jenny Holzer
Jenny Holzer
Jenny Holzer is an American conceptual artist. Holzer lives and works in Hoosick Falls, New York.-Education:...

 created a large light installation with glowing text moving across wide plastic panels. The entire wall, which is 65 ft (19.8 m) wide and 14 ft (4.3 m) tall, changes color according to the time of day. Holzer worked with Klara Silverstein, the wife of Larry Silverstein, to select poetry for the art installation. The wall is structurally fortified as a security measure.

The building is being promoted as the safest skyscraper in the U.S. According to Silverstein Properties, the owner of the building, it "will incorporate a host of life-safety enhancements that will become the prototype for new high-rise construction". The building has 2 ft (60 cm) thick reinforced-concrete
Reinforced concrete
Reinforced concrete is concrete in which reinforcement bars , reinforcement grids, plates or fibers have been incorporated to strengthen the concrete in tension. It was invented by French gardener Joseph Monier in 1849 and patented in 1867. The term Ferro Concrete refers only to concrete that is...

 and fireproofed
Fireproofing
Fireproofing, a passive fire protection measure, refers to the act of making materials or structures more resistant to fire, or to those materials themselves, or the act of applying such materials. Applying a certification listed fireproofing system to certain structures allows these to have a...

 elevator and stairway access shafts. The original building used only drywall
Drywall
Drywall, also known as plasterboard, wallboard or gypsum board is a panel made of gypsum plaster pressed between two thick sheets of paper...

 to line these shafts. The stairways are wider than in the original building to permit faster egress.

7 World Trade Center is equipped with Otis
Otis Elevator Company
The Otis Elevator Company is the world's largest manufacturer of vertical transportation systems today, principally focusing on elevators and escalators...

 destination elevators. After pressing a destination floor number on a lobby keypad, passengers are grouped and directed to specific elevators that will stop at the selected floor (there are no buttons to press inside the elevators). This system is designed to reduce elevator waiting and travel times. The elevator system is integrated with the lobby turnstile and card reader system that identifies the floor on which a person works as he or she enters and can automatically call the elevator for that floor.

Nearly 30 percent of structural steel used in the building consists of recycled steel. Rainwater is collected and used for irrigation of the park and to cool the building. Along with other sustainable design features, the building is designed to allow in plenty of natural light, power is metered to tenants to encourage them to conserve energy, the heating steam is reused to generate some power for the building, and recycled materials are used for insulation and interior materials.

Construction

Construction of the new 7 World Trade Center began on May 7, 2002 with the installation of a fence around the construction site. Tishman Construction Corporation of New York began work at the new 7 World Trade Center in 2002, soon after the site was cleared of debris. Restoring the Con Ed electrical substation
Electrical substation
A substation is a part of an electrical generation, transmission, and distribution system. Substations transform voltage from high to low, or the reverse, or perform any of several other important functions...

 was an urgent priority to meet power demands of Lower Manhattan. Because 7 World Trade Center is separate from the main 16 acres (6.5 ha) World Trade Center site
World Trade Center site
The World Trade Center site , also known as "Ground Zero" after the September 11 attacks, sits on in Lower Manhattan in New York City...

, Larry Silverstein
Larry Silverstein
Larry A. Silverstein is an American businessman, and real estate investor and developer in New York City.Silverstein was born in Brooklyn, and became involved in real estate, together with his father, establishing Silverstein Properties...

 required approval only from the Port Authority
Port Authority of New York and New Jersey
The Port Authority of New York and New Jersey is a bi-state port district, established in 1921 through an interstate compact, that runs most of the regional transportation infrastructure, including the bridges, tunnels, airports, and seaports, within the Port of New York and New Jersey...

 and rebuilding was able to proceed quickly. Building Seven was not included in the original World Trade Center master plan by Daniel Libeskind
Daniel Libeskind
Daniel Libeskind, is an American architect, artist, and set designer of Polish-Jewish descent. Libeskind founded Studio Daniel Libeskind in 1989 with his wife, Nina, and is its principal design architect...

, but was designed by Skidmore, Owings & Merrill
Skidmore, Owings and Merrill
Skidmore, Owings and Merrill LLP is an American architectural and engineering firm that was formed in Chicago in 1936 by Louis Skidmore and Nathaniel Owings; in 1939 they were joined by John O. Merrill. They opened their first branch in New York City, New York in 1937. SOM is one of the largest...

 under the leadership of David Childs
David Childs
David M. Childs is the Consulting Design Partner at Skidmore, Owings and Merrill. He is best known for his redesign of the new One World Trade Center in New York....

, who largely redesigned One World Trade Center.

Once construction of the power substation was complete in October 2003, work proceeded on building the office tower. An unusual approach was used in constructing the building; erecting the steel frame before adding the concrete core. This approach allowed the construction schedule to be shortened by a few months. Construction was completed in 2006 at a cost of $700 million. Though Silverstein received $861 million from insurance on the old building, he still had $400 million remaining in mortgage to pay off. Costs to rebuild were covered by $475 million in Liberty Bonds
Liberty bond
A Liberty Bond was a war bond that was sold in the United States to support the allied cause in World War I. Subscribing to the bonds became a symbol of patriotic duty in the United States and introduced the idea of financial securities to many citizens for the first time. The Act of Congress which...

, which provide tax-exempt financing to help stimulate rebuilding in Lower Manhattan and insurance money that remained after other expenses.

A 15000 sq ft (1,393.5 m²) triangular park was created between the extended Greenwich Street and West Broadway by David Childs with Ken Smith and his colleague, Annie Weinmayr, of Ken Smith Landscape Architect. The park comprises an open central plaza with a fountain and flanking groves of sweetgum trees and boxwood
Buxus
Buxus is a genus of about 70 species in the family Buxaceae. Common names include box or boxwood ....

 shrubs. At the center of the fountain, sculptor Jeff Koons
Jeff Koons
Jeffrey "Jeff" Koons is an American artist known for his reproductions of banal objects—such as balloon animals produced in stainless steel with mirror finish surfaces....

 created Balloon Flower (Red), whose mirror-polished stainless steel represents a twisted balloon in the shape of a flower.

Building opened

The building was officially opened at noon on May 23, 2006, with a free concert featuring Suzanne Vega
Suzanne Vega
Suzanne Nadine Vega is an American songwriter and singer known for her eclectic folk-inspired music.Two of Vega's songs reached the top 10 of various international chart listings: "Luka" and "Tom's Diner"...

, Citizen Cope
Citizen Cope
Clarence Greenwood is an American songwriter and producer. His eclectic mix of blues, laid-back rock, soul, and folk has a large and profoundly dedicated following, built over the past decade of touring due to solid word of mouth....

, Bill Ware Vibes, Brazilian Girls
Brazilian Girls
Brazilian Girls was a band from New York City known for their eclectic blend of electronic dance music with musical styles as diverse as tango, chanson, house, reggae and lounge. None of the members are actually from Brazil and the only female in the band is Sabina Sciubba. Other members include...

, Ollabelle
Ollabelle
Ollabelle is a New York based folk music group named after the influential Appalachian songwriter Ola Belle Reed. The group is composed of five singing multi-instrumentalists hailing from disparate parts of the United States, Canada and Australia.-History:...

, Pharaoh's Daughter
Pharaoh's Daughter
Pharaoh's Daughter is a world music band from New York City. Their music is a mix of American folk, Jewish klezmer, and Middle Eastern sounds.The bandleader is Basya Schechter...

, Ronan Tynan
Ronan Tynan
Ronan Tynan is a singer in the classical Irish style. He is most famous for his renditions of "God Bless America" at Yankee Stadium during important New York Yankees games, such as Opening Day, nationally-televised games, the last game at the old Yankee Stadium, and playoff games...

 (of the Irish Tenors
Irish Tenors
The Irish Tenors is the PBS musical singing trio from Ireland started in 1998 by a group of television producers for a of PBS special The Irish Tenors. They have since recorded 5 PBS specials and 7 albums...

), and special guest Lou Reed
Lou Reed
Lewis Allan "Lou" Reed is an American rock musician, songwriter, and photographer. He is best known as guitarist, vocalist, and principal songwriter of The Velvet Underground, and for his successful solo career, which has spanned several decades...

. Prior to opening, in March 2006, the new 7 World Trade Center frontage and lobby were used in scenes for the movie Perfect Stranger with Halle Berry
Halle Berry
Halle Berry is an American actress and a former fashion model. Berry received an Emmy, Golden Globe, SAG, and an NAACP Image Award for Introducing Dorothy Dandridge and won an Academy Award for Best Actress and was nominated for a BAFTA Award in 2001 for her performance in Monster's Ball, becoming...

 and Bruce Willis
Bruce Willis
Walter Bruce Willis , better known as Bruce Willis, is an American actor, producer, and musician. His career began in television in the 1980s and has continued both in television and film since, including comedic, dramatic, and action roles...

.
Since the building opened, several unleased upper floors have been used for events such as charity lunches, fashion shows, and black-tie galas. Silverstein Properties allowed space in the new building to be used for these events as a means to draw people to see the building. From September 8 to October 7, 2006, the work of photographer Jonathan Hyman was displayed in "An American Landscape", a free exhibit hosted by the World Trade Center Memorial Foundation at 7 World Trade Center. The photographs captured the response of people in New York City and across the United States after the September 11, 2001, attacks. The exhibit took place on the 45th floor while the space remained available for lease.

By March 2007, 60 percent of the building had been leased. In September 2006, Moody's
Moody's
Moody's Corporation is the holding company for Moody's Analytics and Moody's Investors Service, a credit rating agency which performs international financial research and analysis on commercial and government entities. The company also ranks the credit-worthiness of borrowers using a standardized...

 signed a 20-year lease to rent 15 floors of 7 World Trade Center. Other tenants that had signed leases in 7 World Trade Center, as of May 2007, include ABN AMRO
ABN AMRO
ABN AMRO Bank N.V. is a Dutch state-owned bank with headquarters in Amsterdam. It was re-established, in its current form, in 2009 following the acquisition and break up of ABN AMRO Group by a banking consortium consisting of Royal Bank of Scotland Group, Santander and Fortis...

, Ameriprise Financial
Ameriprise Financial
Ameriprise Financial, Inc. is one of the leading diversified financial services companies in the U.S. Ameriprise Financial engages in business through its...

 Inc., Darby & Darby P.C., Mansueto Ventures LLC, business publisher of Fast Company
Fast Company (magazine)
Fast Company is a full-color business magazine that releases 10 issues per year and reports on topics including innovation, digital media, technology, change management, leadership, design, and social responsibility...

 and Inc.
Inc. (magazine)
Inc. magazine, founded in 1979 and based in New York City, is a monthly publication focused on growing companies. The magazine publishes an annual list of the 500 fastest-growing private companies in the U.S., the "Inc...

, and the New York Academy of Sciences
New York Academy of Sciences
The New York Academy of Sciences is the third oldest scientific society in the United States. An independent, non-profit organization with more than members in 140 countries, the Academy’s mission is to advance understanding of science and technology...

.

The space occupied by Mansueto Ventures has been designed to use the maximum amount of natural light and has an open floor plan. The space used by the New York Academy of Sciences
New York Academy of Sciences
The New York Academy of Sciences is the third oldest scientific society in the United States. An independent, non-profit organization with more than members in 140 countries, the Academy’s mission is to advance understanding of science and technology...

 on the 40th floor, designed by H3 Hardy Collaboration Architecture, works with the parallelogram shape of the building. Keeping with the green design of the building, the NYAS uses recycled materials in many of the office furnishings, has zoned heating and cooling, and lights that detect motion, coming on automatically only when people are present, and adjust according to incoming sunlight.

Silverstein Properties
Larry Silverstein
Larry A. Silverstein is an American businessman, and real estate investor and developer in New York City.Silverstein was born in Brooklyn, and became involved in real estate, together with his father, establishing Silverstein Properties...

 also has offices in 7 World Trade Center, along with office space used by the architectural and engineering firms working on 1 World Trade Center, 150 Greenwich Street, 175 Greenwich Street, and 200 Greenwich Street. The building became fully leased on September 2011 when MSCI Inc. was reported to have leased a 125,000 square foot space on the top floor.

See also



External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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