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Visual Evidence, Damage Estimates, and Timeline Analysis (Chapters 1-8) Federal Building and Fire Safety Investigation of the World Trade Center Disaster (NIST NCSTAR 1-5A)



William M. Pitts, Kathryn M. Butler, Valentine Junker


This report summarizes the collection and analysis of visual material used for the National Institute of Standards and Technology (NIST) World Trade Center (WTC) Investigation. The task consisted of four major subtasks: 1) identification, collection, data basing, and cataloging of visual material, 2) timing of material incorporated into the NIST visual database, 3) development of fire time lines and additional analyses based on the visual material, and 4) documentation. Procedures used for subtasks 1 and 2 are summarized. Two data bases were assembled containing 6,899 photographs and 6,977 video clips, with 3,279 of the photographs and 2,772 of the videos timed with 3 second or better accuracy. The primary output of the task is a series of Excel data sheets describing individual window observations (fire, smoke, and whether window is open or closed) on the four faces of both towers as a function of time. Fire behaviors are discussed and documented by a large number of images. Additional analyses include initial façade damage and fire behavior due to aircraft impacts, aircraft speeds, and the motion of WTC 2 resulting from the aircraft impact. Unusual fire behaviors are documented for both towers. Several hanging objects (possibly floor slabs) observed inside WTC 2 and their changes with time are described. Other observations, including falling victims, falling streamers, and smoke marks on façade columns, are documented and related to the observed fire behaviors.
National Construction Safety Team Act Reports (NIST NCSTAR) - 1-5
Report Number
Created December 1, 2005, Updated February 19, 2017