How tall towers can be brought downHow tall towers can be brought down
“Bending and buckling (deformation) of steel beams and columns occurs when the steel temperature exceeds approximately 538 degrees C (1000 degrees F). At elevated temperatures, steel exhibits a progressive loss of strength. When there is a greater fire exposure, the load required to cause deformation is reduced. Deformation is not the result of melting. A deformed element is not one that has melted during the fire, and therefore the occurrence of such deformation does not indicate that the material was heated above its melting temperature.” – Technical Committee on Fire Investigations, Sec. 6.2.9.1, NFPA 921 Guide for Fire and Explosion Investigations (2011 Edition)