DOB Findings and Recommendations for WTC, Feb 2003

NYC 9/11 Public Portal Document

1 Executive Summary I

The September 11, 2001 terrorist attack and subsequent collapse of the World Trade Center were a national tragedy with an enormous impact oh New York City. In light of these events, the Department of Buildings deemed it imperative to establish a Task Force to ensure that requirements, standards and practices in the design and construction of buildings provide safety for occupants of tall buildings. While the Task Force found that the current NYC Building Code contains stringent safety provisions, in a world of unknown and elevated risks we must ensure that our standards are the highest we can make them without compromising our ability to live, ) work, and build in New York City.

The overall performance of the World Trade Center towers and the surrounding buildings t demonstrated a significant ability to protect human life during catastrophic and unforeseen events. As noted in the July 2002 report by the FEMA Building Performance Study Report: 1 The fact that the structures were able to sustain this level of damage and remain standing for an extended period of time is remarkable, and Is the reason that many building occupants were able to evacuate safely. Events of this type, resulting in such substantial damage, are generally not considered in building design, and the ability of these structures tp successfully withstand such damage is noteworthy.

However, as with every major failure of a building or structure in New York City, it is incumbent upon the Department of Buildings to review the events and conditions leading to the failure and the associated standards for the construction and operation of buildings. This report outlines its findings and recommendations.

1.1 Scope and Participation On March 19, 2002 the NYC Department of Buildings convened the World Trade Center Building Code Task Force (Task Force) to review current building design, construction and operating requirements and determine if modifications for extreme events were needed to ensure public safety in new and existing buildings.

The Task Force, made up of an Executive Committee and five Working Groups, represents a i broad coalition of stakeholders and experts from the public and private sectors.

1.2 Sources and Deliberation The Task Force gathered input from other government entities, professional design and engineering societies, the construction industry, private real estate owners associations, private and academic experts, and individuals directly affected by the disaster. Inspection reports, news articles, research reports and, in some cases, empirical test results were also reviewed. A critical source of information regarding the events of September 11th was the FEM A World Trade Center Building Performance Study Report (BPS Report). Its conclusions point to several areas in our current standards and code requirements that may require modification. Based on the above sources, issues were presented to the Executive Committee and Working Groups for deliberation. Working Groups examined the study issues and formulated both general recommendations and specific proposals for Building Code changes where they were deemed appropriate given the limited amount of technical information available.

The Task Force diligently worked to identify and differentiate where information already exists, where it is currently being developed, and where additional study is required to adequately Page 10 WTC Building Code Task Force February 2003 Findings and Recommendations

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