World Trade Center collapse

Tom's three-hour-research *JOM* article that became his most-cited publication, used as an example of (a) the principle that good engineering reasoning can illuminate any subject quickly, (b) the truther-conspiracy follow-on, and (c) the thermal-conductivity error in the truther rebuttal book. The "you don't melt steel in a building fire" point is the technical anchor.

Come to class, ask questions. I would rather answer your question than give a lecture. There are other things on Stellar right now if you want to read things. There's an article that I wrote about six weeks after the World Trade Center collapsed, because I was so sick of reading things in the paper that were just outright wrong about the collapse of the World Trade Center. People said, oh, the fire was so hot it melted the steel. If you could melt steel that easily, we didn't need Henry Bessemer in the 1860s to teach us how to melt steel. You don't melt steel in any type of building fire. I've seen oil rigs where you have a 60-foot flame — I can show you a video of a 60-foot flame in an oil rig and the thing lasts four hours. Finally it collapses, not because the steel melted, but because it just got so hot and so weak it falls over like cooked spaghetti.

Tom's role as published commentator and ongoing target of conspiracy-theorist correspondence. Used pedagogically to show how observed phenomena (sparks during the collapse) admit multiple explanations — thermite reaction vs. electrical arcing of high-power conductors.

There are people who believe the World Trade Center didn't fail because the planes hit it, but because of a government plot — they actually set off thermite reactions inside and cut the beams in two. 18% of Americans apparently believe the US government destroyed the World Trade Center. It's called the 9/11 conspiracy theory. I'm a major foil for this because I wrote an article on the World Trade Center, why it collapsed. As of yesterday — there's something called 9/11 TV, and they sent me two DVDs and they want me to watch their theory. They look at the World Trade Center, see all these sparks coming out, and they say, see, that's proof of a thermite reaction. I said, when did they turn off the electricity in the building? Because if you have a fire and two electrical conductors with four megawatts of electrical power behind them touch each other, you'll get a shower of sparks too. All these things they say are proof usually have another explanation. But I've been listening to this for years on the World Trade Center.

Not a forensic case as discussed here — rather, the paper itself ("Why the World Trade Center Collapsed," Eagar & Musso) as an example of writing-for-non-specialists. Tom contrasts the three hours he spent on it (and its outsized citation impact) with the hundreds of obscure peer-reviewed papers he wrote that nobody read. The paper's substantive content (the steel-melting misconception) is mentioned but not developed in this lecture. ## Figures referenced (not cases)

There's another paper I'm going to give you, "Why the World Trade Center Collapsed." A lot of you have seen this paper before. I give these out to a lot of students. I've written in my career a couple of hundred peer-reviewed publications. I remember the first day I made as an assistant professor, I met with Walter Owen, the department head. He said, no matter what anyone tells you, it really is publish or perish. That was the only advice he gave me in the next six years while I was a young assistant professor. But you have to publish.

Cited rhetorically, not as a developed case. Tom mentions the article he wrote two weeks after the collapse, which led the Google results for "WTC collapse" for nearly a decade. Used to make the writing-for-a-general-reader point — the article succeeded because it was pitched at a high-school science student.

I've given you some other handouts. One's an article I wrote a couple weeks after the World Trade Center collapsed, which for about eight or ten years was the number one article if you looked up Google "WTC collapse." The reason it was the number one article is I was asked by an editor to write it. I was so sick of hearing false information, like the steel melted in the fire. Anyone who's ever been to a fire knows that steel doesn't melt in a fire. If steel melted in the fire, we didn't need Sir Henry Bessemer in 1856 to teach us how to melt steel — we would have been melting it for a few thousand years before that. I wrote this in three hours, which is less time than it took for me to write any of my several hundred publications. I've gotten more comments on this, positive and negative, than any paper I've ever written, or actually all of the papers combined. Why? Because I wrote it for a high school science student. I was trying to write it so someone could understand it.

First of all, you have to know who you're writing for. There's an article I wrote. Joel Clarke was asked to write an article on the World Trade Center a couple weeks after it collapsed, and he said, "Oh, that's Tom Eagar." So the journal editor called me in. I was so sick of hearing the news reports about the steel melting. I'd been to fire scenes — no steel melts in a regular fire, and I knew that. So I wrote an article. I spent about three hours writing this paper, and within six months it was the most requested or most read article on the World Trade Center, and it stayed there for about nine years, even ahead of the government report. The reason is because I knew who I was writing it for. When I sat down to write this, I said, I'm going to write this for a good high school science student. I want to write it so that people can understand it. You don't have to be a scientist to understand this. As a result, a lot of people liked it and could understand it. But also as a result, a lot of people hate me. There are whole websites — they were writing to the president of MIT saying I should lose my tenure, he's just a government shill. Anybody who knows me knows I'm not a government shill.

Tom mentions his WTC paper as a course handout, notes it was long the top-Googled WTC-collapse article, and flags an upcoming BBC documentary interview. Asserts "it was the airplanes" against conspiracy theorists.

There's a copy of my World Trade Center paper. We'll probably talk about that at some point. For a long time, that was the most referenced article on the World Trade Center collapse. I was number one on Google, I think I'm number two now. All the conspiracy theorists hate me because I explained it. In fact the BBC is doing a documentary, and next Thursday — not this Thursday but next Thursday — I'll be down in the Washington area and they want me to meet with them, because they're doing a documentary on the World Trade Center. By the way, it was the airplanes. It wasn't a government conspiracy. I'll tell you some of my favorite stories on those things later. It's amazing what people can believe.

Used as an example of writing simply and quantitatively; also as anecdote about online conspiracy attacks on Tom.

One important teaching secret is: why would someone spend an entire lecture doing a derivation on the board? You've all been in an engineering class or a science class where they solve some fourth-order partial differential equation, and they screw it up all the time. Why would they do that? The simple answer is they didn't have time to prepare a lecture. There are some articles to read. I suggest you read "Why Did the World Trade Center Collapse?" — not because I wrote it, but I did. And for nine years I was number one. If you looked up "WTC collapse" on the internet, you would find this paper was number one. The reason was, I wrote it simply. So this is, I think, an example of how I would like you to write your papers. It's also quantitative. I put real numbers in there. I've also become the brunt of all the conspiracy theorists in the world about the World Trade Center. They've had websites against me and they've written to the president of MIT saying I should lose my tenure because I'm a shill for the government. I'm just trying to make America great again. Geez.

The American Welding Society structural welding code has a static and a dynamic side. Static for buildings is 5/3. The World Trade Center was 5/3. I gave you an article I wrote, and I used that 5/3. That building would have been built to the AWS structural welding code. The AWS structural welding code is a companion to the boiler code — something for bridges dynamic, something for buildings static. Bridges are dynamic with trucks going over them — dynamic why? Because you've got fatigue. Buildings, it's not really fatigue, not at the high level of stress. So those things make sense.

Tom's three-hour-write *Journal of Metals* article. Used as the pedagogical model for the course: write so a high school senior can follow it, but anchor in fundamental principles (color pyrometry, Planck's law). The conspiracy-theorist response and the 500°F vs. 900°F dispute.

If I knew how to teach it, I would try to do that for you too. I don't know exactly how to teach it, but I'm going to hand out a paper which out of my several hundred publications is the most referenced paper I've ever written. It took me less time to write this paper than any other paper I've ever written. About three hours. Two weeks after the World Trade Center collapse, the editor of the Journal of Metals called Joel Clark first — Professor Clark — and said, "Would you write an article on the World Trade Center collapse?" He says, "Well, why don't you call Tom Eagar?" So he called me. I was so sick of hearing people tell me in the newspapers, "This fire was so hot that it melted steel."

To give you an example of some of the things I just said: I was asked in late September of 2001, right after 9/11, by the editor of a metallurgical journal if I would write an article. Actually he didn't ask me, he asked Professor Clark, and Professor Clark said, "Oh, you ought to get Professor Eagar to do it." So he asked me, and I was so sick and tired of reading newspaper accounts about how the steel melted in the fire of the airplanes. Anyone who's ever been to a fire scene knows that steel doesn't melt in a fire. If steel melted in a fire, why did we need Sir Henry Bessemer in 1856 to tell us how to melt steel? The typical temperature of a fire is about 1,000° centigrade. Steel melts at 1500. I've seen a steel derrick where they had a blowout at 10,000 PSI of natural gas from a gas well in Oklahoma, and it catches on fire for three days, and the flames are 300 feet in the air, and the whole derrick is engulfed in flames for three days, and the steel didn't even transform to austenite above 900 centigrade. And I'm reading these great scholars, the newspaper reporters, talking about — or they interview great experts — "Well, the steel melted in the fire."

Towers were built to 1.67 safety factor and survived the airplane impact as designed. Failure was from 20,000 gallons of jet fuel fire per floor, which exceeded combustible-load fire design basis. Code response was not to increase steel (Tom argues this would have priced people out of buildings) but to improve egress standards and public announcement protocols. No-fly zone post-attack prevented rooftop helicopter rescue of victims above the fire floors.

Not necessarily the safety factor, but the design rules. For example, the Twin Towers were built to a safety factor 1.67. They were designed to survive an airplane impact, and they did. It was the fire afterwards. They were designed to survive fires, small fires like the combustibles in the room. They weren't designed to survive 20,000 gallons of fuel on one floor all at once. You can see some pictures where the whole floor is glowing red, and all the beams everywhere were getting weak, and eventually they just started pancaking and going down. What they tightened up after the World Trade Center was not, well, we've got to start putting more steel in buildings — you can barely afford to build the buildings anyway. If you double the steel, you've got to make not just the steel but the windows, everything else goes up in price.

Tom's 2001 paper, written in three hours for a non-technical audience, is given to students as both a content reference (steel does not melt in ordinary fires) and a methodology example (writing for the lay reader). The paper has generated ongoing correspondence including continuing emails from conspiracy theorists fifteen years later.

I handed out a paper on the World Trade Center. I wrote this paper because some editor of a journal asked Professor Joel Clark about three weeks after the World Trade Center collapse if he would write an article. He said, well, why don't you ask Tom Eagar. I was so sick of reading newspaper articles about how the steel melted in the fire that I said yes. Any idiot who's ever been to a fire scene knows that steel doesn't melt in a regular old fire. But all the editors and reporters didn't know that. So I decided to write a paper.

Methodological aside on writing about a subject when you have no specialized expertise — go back to freshman physics and chemistry. Tom's paper as an example.

I handed out the World Trade Center paper. I spent three hours putting that paper together. I've had more comments on that than all the other several hundred publications combined. I wrote it because I was tired of hearing all this stuff that I knew was false, but I really didn't know anything about the World Trade Center. But I did know some basic physics and chemistry. What can you say about something when you know nothing at all about a subject? You can go back to your freshman physics and chemistry and start saying, what do I know? I knew about flames and thermodynamics and flame temperatures and various things, and that's what I wrote about. It still stands today. I just got a nice letter from some lady this weekend who was reading it because of 9/11. She thanked me for writing it. I wrote it because I'd done less work on that than anything else I'd ever worked on. But I wrote it in a way that people could understand, and on a subject people cared about, as opposed to my research — no one cares about my research. It's too specific, too narrow. People want to know about bigger, broader things, which is what I lecture about.

Tom's December 2001 JOM article (with co-author Christopher Musso) explaining the structural failure mode. Used pedagogically as the prime example of "write it so high schoolers can understand," and as the entry point for his lifelong argument with the 9/11 truther community. Three towers, each with 20,000 gallons of fuel; steel lost ~70% strength; not melted.

We talked about communications. When I started as a young faculty member, my department head Walter Owen brought me in and said, no matter what anyone else does, publish or perish. So I published papers and graduate students and research articles. But what happened is, after the World Trade Center collapse, about three weeks afterwards, Joel Clark got a request from the editor of a metallurgical journal saying, will you write an article about the World Trade Center collapse? Joel said, well, ask Tom Eagar. So they asked, would you write an article for the Journal of Metals, JOM? This was published in December 2001. It took me about three or four weeks to gather some information and write this article. Christopher Musso, my graduate student, helped me with some research, so he's co-author. The reason I was willing to write it: I was sick of hearing all the misinformation and incorrect information that was in the press.

Tom's National Geographic special appearance. Used to demonstrate (a) what shaped charges actually do and (b) that the thermite-reaction conspiracy theory was disproven by full-scale testing at the New Mexico Tech explosives research center.

[Tom produces a shaped-charge copper piece.] This is a shaped charge piece of copper. It's a saucer-shaped piece, and it's got little places where you would put a little bit of explosive in each one. When you set it off, the saucer inverts — you'll have a downward force on the outside rim, the thing inverts, and all the copper is squeezed into the center underneath. As it does that, you'll have adiabatic heating and the copper will melt, and you'll shoot out a jet of liquid copper. That jet will penetrate a piece of steel to about whatever the length of the piece of copper is, and it will do it in microseconds. So this is one shaped charge design.

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.

Tom's three-hour-written 2001 article for a metallurgical journal — produced from chemistry, physics, and fire-investigation first principles without specialized prior knowledge. Used to illustrate (a) the Tufte "fuzzy writing = fuzzy thinking" principle Tom was applying, (b) the unexpected reach of clear technical writing pitched at high-school level, (c) the conspiracy-theory backlash he received. Tom assigns the article as a reading.

There is an article on why the World Trade Center collapsed. I give you this because it's an article I wrote. I was asked, three weeks after the World Trade Center collapsed, by the editor of a metallurgical journal if I would write something. I was so sick of hearing all the falsehoods — fake news, I guess is the term today — that were being put out in the press. I said okay, I'll write an article. I spent three hours, with the help of a student, writing this article. I really didn't know much of anything about the World Trade Center, but I knew some chemistry and I knew some physics and I had done some fire investigations, so I just talked about what I knew and what the scientific principles were. And I also knew — remember, fuzzy writing is the result of fuzzy thinking — I was going to pitch it to a high school science student, that was the level.