Buildings, bridges, and other structures are not supposed to fall down. But sometimes they do, and for different reasons: fire, earthquakes, high winds, errors in design and construction, flaws in materials, and even terrorist attacks. The Disaster and Failure Studies Program uses authorities granted by the National Construction Safety Team (NCST) Act, the National Earthquake Hazard Reduction Program (NEHRP), the National Windstorm Impact Reduction Program (NWIRP), and the NIST Organic Act to establish teams to assess building and infrastructure performance and emergency response and evacuation procedures in the wake of disaster and failure events that have resulted in substantial loss of life or posed significant potential for substantial loss of life.
The objectives of NIST's disaster and failure studies may include (1) establishing the likely technical factor or factors responsible for the damage, failure, and/or successful performance of buildings and/or infrastructure in the aftermath of a disaster or failure event; (2) evaluating the technical aspects of evacuation and emergency response procedures that contributed to the extent of injuries and fatalities sustained during the event; (3) determining the procedures and practices that were used in the design, construction, operation, and maintenance of the buildings and/or infrastructure; (4) recommending, as necessary, specific improvements to standards, codes, and practices as well as any research and other appropriate actions based on study findings. NIST studies are documented in technical reports containing data, findings, and recommendations for consideration by private sector bodies responsible for developing relevant national building and fire model codes, standards and/or practices; federal, state and local building and fire officials for adoption and enforcement of national model codes and standards; and research performing organizations such as universities, national laboratories, and private sector entities. NIST promotes, enables, and tracks adoption of recommendations through improved standards, codes, and practices as well as any research and other appropriate actions based on study findings.
The primary focus of disaster and failure studies is on events that occur within the United States and its territories, however, NIST may conduct reconnaissance of international disaster or failure events when lessons can be learned that are relevant to U.S. construction. NIST's involvement in international disaster or failure studies generally will be undertaken in cooperation with other U.S. agencies, industry or private organizations, governments of other nations, or international organizations, for the purpose of establishing and/or improving U.S. practices, codes, and standards.
NIST uses a set of defined decision criteria, including the mortality, exposed population, hazard and/or failure intensity, consequences to resilience, and evacuation and emergency response challenges to determine whether to conduct a Preliminary Reconnaissance. To the extent practicable, NIST will deploy a preliminary reconnaissance team in a timely manner after a disaster or failure event. The NIST Director will consider the evaluation results from using the decision criteria, outcomes of the preliminary reconnaissance, as well as factors including staff availability, resource availability, staff safety, and the quality and adequacy of information and artifacts available to conduct a meaningful study in considering whether to establish an NCST Technical Investigation. Congress or the Administration may also issue a directive to respond to an event, which will result in a Preliminary Reconnaissance or a Technical Investigation being conducted, based on written criteria and procedures.
NIST may use any one or a combination of the study options below in conducting a preliminary reconnaissance or a technical investigation:
NIST has more than 40 years of experience studying building fire and structural failures. Since NIST is not a regulatory agency and does not issue building standards or codes, the institute is viewed as a neutral, "third party." Other federal agencies and state and local governments, as well as private-sector and non-profit organizations, may request assistance in conducting building fire and failure investigations.
Typically, NIST researchers conduct an extensive field study at a disaster site to determine conditions before and after failures. Documents such as drawings, specifications, and inspection reports, as well as eyewitness accounts and videos, are reviewed to gain information about the design and construction of structures, and the events of the actual failure incident. When necessary, laboratory tests are conducted to determine physical properties of failed materials. NIST may fabricate mockups or replicas of structure parts and test these. In addition to laboratory tests, analytical models and computer simulations may help determine likely causes of failure.
The NIST laboratories are well-equipped to conduct investigations. For example, NIST has several types of universal testing machines that can apply tension and compression forces on structural components up to 18 meters (60 feet) tall. Other labs include a large fire laboratory with the capability of conducting well-controlled experiments in fires releasing heat up to 10 megawatts (typical of a multi-room fire).
By understanding the technical causes leading to structural failures and then making that information public, NIST engineers and researchers strive to prevent similar failures in the future. Studies conducted by NIST have led to significant changes in practices, standards, and codes to enhance the health and safety of the American public. Examples include: