World Trade Center collapse article

Tom's 2001 article (written three weeks after 9/11) used as a handout to teach flame chemistry. The teaching point: steel did not melt — it can barely be melted with oxy-acetylene in air. Bessemer's 1856 process exists *because* melting steel is hard.

The first thing we need to know is, if we want to know the temperature of a flame, what's the enthalpy of the reaction? How much chemical heat is released when we burn this fuel? We then also need to know the stoichiometry — do we have the right ratio of hydrogen and oxygen? And we need to know if we have any inerts left over, such as nitrogen. If I have nitrogen, the nitrogen is just carried along as baggage. I gave you a copy — actually I told you to pick one up, but there's one in the packet too in black and white. This is my World Trade Center paper. About three weeks after the World Trade Center, a metallurgical editor asked me if I'd write an article. I was so sick of hearing people say that the steel melted in the fire — it's all over the news, and I knew it wasn't true. Because I teach combustion. If I could melt steel that easily, then we didn't need Sir Henry Bessemer in 1856 to teach us how to melt steel and bring us into the steel age. You can barely melt steel with an oxy-acetylene flame, and you certainly can't melt it in the air.