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Computer Simulation of the Fires in the World Trade Center Towers. Federal Building and Fire Safety Investigation of the World Trade Center Disaster (NIST NCSTAR 1-5F) ***DRAFT for Public Comments***



Kevin B. McGrattan, Charles E. Bouldin, Glenn P. Forney


This report presents the results of numerical simulations of the fires in World Trade Center (WTC) 1 and WTC 2 on September 11, 2001. The calculations were performed with the National Institute of Standards and Technology (NIST) Fire Dynamics Simulator, a computational fluid dynamics model that describes the flow of smoke and hot gases from a fire. Before performing the simulations, the model was validated by comparing its predictions with measurements from a series of large scale fire experiments performed at NIST. The model also was enhanced to better describe the pyrolysis of charring fuels, like wood; and the computer program was re-configured to run on multiple processors. Input data for the simulations of WTC 1 and WTC 2 consisted of descriptions of the properties of typical office furnishings and jet fuel, floor layouts, exterior damage, and interior damage estimates. Results of the simulations were compared with visual observations. Predicted temperatures and gas concentrations were subsequently used to analyze the temperatures within steel trusses and columns.
National Construction Safety Team Act Reports (NIST NCSTAR) - 1-5
Report Number


World Trade Center, high rise buildings, building collapse, disasters, fire safety, fire investigations, terrorists, terrorism, computer simulation, computational fluid dynamics, smoke flow, high temperature gases, large scale fire tests, pyrolysis, wood, floors
Created September 1, 2005, Updated February 19, 2017