Science Behind How the Towers Fell Peer Reviewed
Overview
The collapse of the WTC buildings post-obit the terrorist attacks on September eleven, 2001, was ane of the worst building disasters in US history, killing 2,749 people, including 400 emergency responders.
NIST responded to calls from Congress and the public to conduct out a federal investigation of why the buildings collapsed, the evacuation of building occupants and the emergency response. NIST was given this authority when Congress passed, and the President signed into law, the National Construction Prophylactic Team Deed of 2002.
More than 200 professionals and technical subject matter experts, including 85 NIST staff members, answered the phone call and participated in the investigation.
As part of the investigation, the NIST team gathered every bit of evidence they could find. Activities included:
- Interviews with ane,056 surviving occupants of the WTC buildings and 116 emergency responders.
- Extensive reviews of design, structure, maintenance and inspection documents for the buildings
- Examination of hundreds of structural steel components from WTC buildings
- Gathering and analyzing thousands of pieces of video, photographic, and audio evidence from professional sources and the public
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The Reports
Throughout the procedure, NIST held 23 public meetings and provided multiple opportunities for the public to review and comment on drafts of the reports. In add-on, all of the reports were reviewed by an external, non-NIST NCST advisory committee.
In the terminate, NIST released last versions of the 43 reports on the WTC towers, totaling some ten,000 pages, on October 26, 2005. NIST released concluding versions of the iii reports on WTC vii, totaling virtually one,000 pages, on November 25, 2008.
NIST is aware of other studies related to the WTC collapse and stands by its original findings.
The Legacy
Building and Burn Codes, Standards and Practices
The WTC investigation has had a significant legacy. In the reports, NIST fabricated 31 recommendations for improvements to edifice and burn codes, standards, and practices based on the WTC investigation. While the federal regime has no regulatory authority for edifice and fire codes, many U.Due south. codes and standards were subsequently updated to improve areas such as structural integrity, burn down resistance, occupant evacuation and emergency responder communications. NIST's recommendations have had a significant affect on design and construction practices for high-ascension buildings worldwide, including the new buildings at the rebuilt World Trade Center site.
In addition, NIST scientists conducted tests of steel from the WTC buildings to measure their mechanical properties at normal and elevated temperatures. These tests led to the evolution and validation of functioning criteria for burn resistive steel. This blazon of steel, which was not available at the time the WTC was built, would not necessarily prevent a building from collapsing during a burn, simply it would give occupants more time to escape.
DNA Identification
NIST also played a role in the effort to identify the victims of the 9/eleven attack. This effort was at the time — and still is — the largest forensic identification effort ever undertaken. This endeavor was particularly challenging because in many cases the Deoxyribonucleic acid of the victims was severely degraded by exposure to intense rut from burning jet fuel, equally well every bit moisture and disuse in the weeks and months following the assault. To brand an identification, experts analyzed segments of Dna called forensic markers. When Deoxyribonucleic acid degrades, these forensic markers break autonomously, which makes them difficult to analyze.
To cope with this challenge, researchers at NIST, Ohio University and Bode Technology developed new forensic markers involving shorter segments of Deoxyribonucleic acid, which by virtue of their small size are more likely to remain intact as the Dna degrades. This effort allowed forensic experts to identify thousands of remains that otherwise would take never been returned to their families. The research conducted at NIST in the backwash of ix/11 led to the evolution of new "mini-markers" that are now routinely used in criminal casework. These markers have helped investigators solve endless sexual assaults, homicides and other crimes that would otherwise accept gone cold.
Public Safety Communications
Among the victims were more than 400 first responders, including firefighters, police force officers, and Port Dominance officers. These deaths revealed a huge gap in public safety communications and fundamentally changed NIST's research focus in public safety communications. During the disaster, offset responders struggled to communicate due to lack of interoperability amid the radio systems and over-crowded advice channels. Equally a result, the 9/11 Committee made communications research for public condom a priority, and tasked NIST with finding solutions.
NIST established its Public Safety Communications Research division and became a technical advisor to Congress and the White House on issues surrounding public safety communications. This new research focus helped established FirstNet, a nationwide broadband network dedicated to first responder communications. In the 20 years since the attacks, NIST and its partnering research organizations and industry accept resolved many of the radio interoperability issues and now focus on modernizing communications technology for first responders.
National Fire Enquiry Laboratory & Disaster Resilience Program
As a result of the WTC investigation, NIST established the National Fire Research Laboratory, which has provided a unique capability to test performance of big-scale structures under realistic conditions. NIST likewise established a Disaster Resilience Program, focused on ways to amend the safety and resilience of buildings and communities in the face of multiple threats including wildfires, hurricanes, tornadoes and earthquakes. Improving resilience has emerged as a major theme of the 21st century, and the NCST Act, created in response to 9/11, has enabled NIST to conduct technical investigations of subsequent significant disasters. including the Joplin, Missouri, tornado in May 2011; the 2003 Station nightclub fire in Westward Warwick, Rhode Isle; the effects of 2017's Hurricane Maria on Puerto Rico and, most recently, the Champlain Towers Plummet in Miami, Florida, in June 2021.
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Source: https://www.nist.gov/world-trade-center-investigation
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