Dr. Arden L. Bement, Jr.
Director
National Institute of Standards
and Technology
United States Department of Commerce
House of Representatives
United States Congress
March 6, 2002
Good
afternoon Chairman Boehlert, Ranking Member Hall, and Members of the
Committee. I want to thank you for this
opportunity to testify on the investigation into the collapse of the World
Trade Center Towers. The tragedy that
the United States experienced on September 11, 2001, was unprecedented when
compared with any prior accident, natural disaster, or terrorist/war attack. The collapse of the twin World Trade Center
towers was the worst building disaster in human history. Engineers, emergency responders, and the
nation did not anticipate, and were largely unprepared for, such a
catastrophe. Among other national needs,
these events highlight the following technical priorities:
·
To establish the probable
technical causes of the collapses and derive the lessons to be learned;
·
To develop and disseminate
immediate guidance and tools to assess and reduce future vulnerabilities; and
·
To produce the technical
basis upon which cost-effective changes to national practices and standards can
be developed.
Shortly
after the attacks on the World Trade Center, NIST’s building and fire
researchers began assisting federal and local agencies in many ways to
investigate the spread of fire through the buildings and their subsequent
collapse. Our researchers used
previously developed models along with preliminary information from videos of
the attack and other sources to simulate the spread of fire and smoke in the
buildings. At the request of the Federal
Emergency Management Agency (FEMA), NIST conducted a comparison and analysis of
the current building and fire codes of New York City with national codes, and
we contributed to the Army Corps of Engineers’ study of the structural and fire
damage to the Pentagon. In addition,
NIST experts participated in the initial assessment of the collapse conducted
by the American Society of Civil Engineers (ASCE) Coalition that comprised a
Building Performance Assessment Team (BPAT) funded by FEMA. The ASCE Coalition Team also included
professional members of the Society of Fire Protection Engineers (SFPE), the
National Fire Protection Association (NFPA), the American Institute of Steel
Construction (AISC), and the Structural Engineers Association of New York
(SEAoNY). NIST is lending its expertise in structural
disasters to ASCE and the Structural Engineers Association of New York (SEAoNY)
to store WTC steel at its Gaithersburg, MD, headquarters for further scientific
study.
However, more needs to be
done. A growing number of technical
experts, industry leaders, and families of victims are pressing for a
broad-based Federal investigation to study the building construction, the
integrity of the materials used, and all the technical conditions that combined
to cause the building disaster at the World Trade Center [Witness would like to submit for
the record, letters received supporting a federal investigation]. NIST has begun working informally with a
coalition of organizations – representing key industry, standards, codes, and
professional groups – in an effort to launch a comprehensive public-private
response program that includes such an investigation. NIST is also working very closely with FEMA,
since an in-depth technical investigation would go well beyond the scope of the
building performance assessments conducted by FEMA following major
disasters. The implementation of the
results of such an investigation would be critical to restore public confidence
in the safety of tall buildings nationwide, enhance the safety of fire and
emergency responders, and better protect people and property in the
future. To cite one example, the
February 4th issue of “Crain’s New York Business” reports that an increasing
number of tenants are leaving the Empire State Building, which is again the
tallest building in New York City, because of fears of another terrorist
attack. Anecdotal evidence also suggests
that building vacancy rates have doubled in Manhattan, despite the 15 million
square feet of space that was lost on September 11th.
NIST has received policy
approval from the Secretary of Commerce to initiate and, after consultation
with local officials, to conduct an independent and comprehensive “National
Building and Fire Safety Investigation of the World Trade Center Disaster”
under NIST’s existing legislative authorities (15 U.S.C. 281a). Among Federal laboratories, NIST
is uniquely qualified to conduct such a comprehensive investigation. The Building and Fire Research Laboratory is
the foremost fire research laboratory in the United States, and through the
National Earthquake Hazards Reduction Program (NEHRP) NIST is the principal
agency for research and development to improve building codes and
standards. NIST has extensive experience
and expertise in conducting disaster investigations following
structural/construction failures, fires, earthquakes, hurricanes, and
tornadoes. These have included the
well-known investigations into the 1981 collapse of a walkway in the Kansas
City Hyatt Regency Hotel, the 1986 Dupont Plaza Hotel fire in San Juan Puerto
Rico, the 1994 Northridge earthquake collapses, and the 1995 Kobe, Japan
earthquake building collapses, to name just a few. In compliance with statutory requirements
NIST has already consulted with local authorities in New York, including the
Port Authority of NY & NJ, the Mayor’s Office of
Emergency Management, the New York City Department of Design and
Construction, and the Fire Department of New York. These organizations have expressed support
for NIST and agreed to cooperate in its it’s
investigation.
The proposed
investigation wouldwill
involve world-class experts from industry, academia, and other laboratories to
complement NIST’s excellent in-house technical expertise. Supplementing the outstanding work done
through the building performance assessment team initially assembled through
FEMA, NIST would willdelve
deeper into the factors related to the collapse. NIST would use the results of the soon to be
released ASCE Coalition team’s study as a valuable source of input into the
investigation. The objectives of the
NIST investigation would be to determine technically:
·
Why and how the World Trade
Center buildings collapsed following the impacts of the planes;
·
Why the injuries were so
high or low depending on location, including all technical aspects of fire
protection, response, evacuation, and occupant behavior and emergency response;
·
Whether or not
state-of-the-art procedures and practices were used in the design,
construction, operation, and maintenance of the World Trade Center Buildings;
and
·
Whether there are new
technologies or procedures that should be employed in the future to reduce the
potential risks of such a collapse.
The NIST investigation would
focus primarily on World Trade Center Buildings 1 and 2 (the Twin Towers) for
several reasons. First, the collapse of
the Towers was the triggering event that caused much of the collateral damage
to the adjacent properties. Second, many
structural and fire protection design features and construction details found
in the Towers are widely used in the building construction industry. Third, to study procedures and practices
used to assess the safety of innovative structural systems and building designs
not covered by existing building codes or prior in-use experience as was the case of the twin towers, and whether such
practices are adequate to detect and remedy inherent vulnerabilities. Fourth, to study procedures and
practices used to provide adequate structural reserve capacity to resist
abnormal loads (e.g. blast, explosion, impact due to aircraft or flying debris
from tornadoes, accidental fires, and faulty design and construction),
especially those that can be anticipated prior to construction (e.g. impact of
a Boeing 707). Fifth, the Twin Towers would provide the opportunity to study
the effectiveness of fire protection and firefighting technologies and
practices for tall buildings, including emergency mobility and egress,
and communication systems. And lastly, the analytical tools used in
these investigations would be experimentally verified and widely applicable to
other building types. Besides the Towers, the investigation would possibly
consider examining WTC Building 7, which collapsed later in the day.
NIST would use an open and inclusive process
in formulating its work plan for the investigation. This would involve the participation of
technical experts from industry, academia, and other laboratories as well as
liaison with federal, state, and local authorities. NIST would expect to
complete its investigation and issue a final report in 24 months.
The results of the proposed
investigation would be extremely valuable in establishing the probable
technical causes of the disaster and deriving the lessons to be learned, but it
would be meaningless unless we take the knowledge gained and put it to
practical use. That is why NIST, in
partnership with FEMA and a number of private sector organizations, has
developed a broader response program.
This broader program would address critically and urgently needed
improvements to national building and fire standards, codes, and practices that
have begun to be recognized in recent years. The events of September 11th
have brought even more focus and priority to this already important issue.
The goal of this broader
program would be to produce cost-effective retrofit and design measures and
operational guidance for building owners and emergency responders. The program would develop and disseminate
guidance and tools to assess, and produce the technical basis and recommendations
for cost-effective changes to reduce vulnerabilities.
Over the course of the
proposed investigation and broader program there would be a number of
short-term and interim work products that would provide guidance, tools, and
technical assistance to better prepare facility owners, contractors, designers,
and emergency personnel for future disasters.
Some of these products, based on prior NIST work, would be disseminated
broadly as soon as possible. Others that
need further refinement would be disseminated within a year, and the rest after
the completion of the investigation. I
would like to note that the President’s FY 2003 budget request for NIST
contains a $2 million funding increase, which will go towards this effort and
related research.
Let me now give you three examples of work
that would be accomplished through this broader program.
First, fire played a
critical and visible role in the collapse of the WTC buildings and contributed
to damage to the Pentagon buildings.
Current building design practice does not consider fire as a design
condition. Instead, structural fire
endurance ratings are prescribed in building codes using standard tests on
individual components. The current
testing standards are based on work carried out at NIST in the 1920s. They do not represent real fire hazards in
modern buildings. They also do not
consider the fire performance of structural connections or of the structural
system as a whole, or the multiple performance demands on fire proofing
materials. NIST now has the capability
to simulate building fires on the computer to explain critical events and
outcomes to an extent previously not possible.
The proposed work would expand on this core competence in computational
methods, and adapt measurement techniques and test methods to support the
prediction of performance of building materials, products, structural elements,
and systems up to the point of the collapse of a tall building due to
fire. In short, NIST would provide the
technical basis and guidance for fire safety design and retrofit of structures,
the predictive tools and test methods for fire resistance determination, and
the performance criteria for fireproofing materials. In addition, NIST proposes to develop
guidance and retrofit technologies to enhance building egress in emergencies,
practical tools and guidance to enhance the safety and effectiveness of fire
and emergency responders, and improved models of occupant behavior and response
to enhance evacuation and communication in emergencies.
Second, progressive
collapse – which refers to the spread of failure by a chain reaction that
is disproportionate to the triggering event – was also responsible for the
extraordinary number of deaths in the 1995 bombing of the federal building in
Oklahoma City. Yet, the United States
has not developed standards, codes, and practices to assess and reduce this
vulnerability. Adding to the problem for
modern structures is their smaller margin of safety – and the reserve capacity
to accommodate abnormal loads – due to increased efficiency in the use of
building materials and refinements in analysis techniques. The work carried out at NIST in the early
1970s continues to provide the basis for the extremely limited guidance that is
available in current United States standards.
NIST would develop cost-effective solutions to reduce building
vulnerability to progressive collapse using a multi-hazard approach that
exploits synergies in resisting extreme loads from blast, impact, earthquakes,
and fires.
Third, vulnerability
reduction of commercial and institutional buildings and facilities. The
overwhelming majority of buildings in public use today are vulnerable to
terrorist attack on a number of fronts. Most lack state of the art sensing and
information management systems. Few have
electronic representations of the building documents or models, and standards
do not exist for such representations.
Most are not protected against chemical, biological, and radiological
(CBR) threats. While efforts are
underway to protect military buildings through Department of Defense's “immune
buildings” program, there are no standards and practices for civilian
buildings. NIST proposes to work with
the DoD to develop guidelines and advanced technologies to reduce the vulnerability
of such buildings to CBR attacks. NIST
also proposes to work with industry to develop standards for building
information models and information exchange, and practicable tools for helping
building owners make reasoned economic choices in reducing the vulnerabilities
of their buildings.
The final program element
supports a construction-industry-led roadmapping effort to reflect changed
priorities for development and deployment of safety and security standards,
technology, and practices. It would also
support the delivery and dissemination of practical guidance, tools, and
technical assistance to better prepare facility owners, contractors, designers,
and emergency personnel to respond to future disasters and to speed economic
recovery within the industry following disasters. The effort would complement and support
parallel efforts of technical organizations to improve standards, codes, and
practices.
In conclusion, I believe it
is imperative for the U.S. to learn from the worst-ever building disasters in
human history and take aggressive remedial action to minimize future
losses. As the events of September 11
demonstrated, the very stability of U.S. commerce and our economy depends upon
major buildings and critical facilities that provide a key part of our Nation’s
physical infrastructure. In the wake of
September 11th, the private sector’s willingness to take necessary
corrective action to strengthen building codes and standards is extraordinarily
strong. So with the envisioned Federal
technical leadership and partners from the private sector, changes can be made
to minimize the likelihood and consequences of future disasters. Thank you, Mr. Chairman. I would be happy to take questions from the
Committee.