Plain and simple. The failure of the structure was due mostly to thermal expansion. You see, Terral would like you to think that the connections and steel columns/beams needed to reach temperatures of 2800F in order to MELT. The columns, connections, and beams didn't need to melt to cause structural failure in the building. Think of this. If you have two columns with a beam between them bolted to each and applied heat to the beam, what happens? The steel GROWS as it is heated. One inch of steel grows .00000645 of an inch per degree F. So a 30 foot beam equals 360 inches. 360 x .00000645 equals .002322 inches. .002322 inches x 100F equals .2322 inches. So a 30 foot beam at 100F grows almost a 1/4 inch. According to NIST, the fireproofing kept the temperatures of the columns in WTC7 to 570F and no higher. So 30 feet of steel column at 570F would have grown by (570F x .002322 equals 1.32 inches) more than 1 1/4 inches. According to NIST, the floor beams in the east side of the building reached 1, 100F. So a 30 foot beam would have grown (1,100F x .002322 equals 2.5543 inches) over 2 1/2 inches. What does that do to the bolted connections on the columns? Let's look at this. I worked in steel mills. They use steam and superheated steam all the time. Here is a picture what they call an "expansion loop" designed into the steam line. As the pipelines grow and shrink from use, the two lower "elbows" grow toward and shrink away from each other. The pipes utilize what's called a "roller" to allow the pipe to expand/contract. Here is a picture of a roller which is installed under the pipe. Here is a drawing of where the "roller" is located under the pipe. I have seen welded pipe supports sheared off of support beams because of improper placement of expansion "rollers" and "expansion loops". What do you think happens to the bolted connections of floor beams? Steam in steel mills run at temperatures of 500F to 1100F. Not only did we have thermal expansion amongst the beams/columns, but let's throw in the fact that the steel columns and beams also WEAKENED due to the fire. Did you ever turn on your hot water at home and hear the "creaking" noises? That's the copper pipes expanding due to the hot water running through them. So now we have connections popping from thermal expansion, but add in the strength of the steel weakening. This all lead to the collapse of the main column in the building, below the mechanical penthouse, which has been shown to have collapsed in the video I present and why Terral only shows you the part of the video AFTER that happens. Quite dishonest eh? So, the columns did not need to "melt" for the steel structure to fail. This is why they use arguments like "melted steel" and "no fire can melt steel". They don't understand thermal expansion and steel weakening and try to divert people away from the actual explanation. This is why Dr. Quintiere says HIS theory is that heat caused the CONNECTIONS to fail, not the beams as NIST says. THAT'S why he wants the study to be looked at again. Not because of thermite or explosives. The fact still remains that Terral disproves his own claims about thermite being used when he says that no "burning" or "melting" is evident in this next photo that HE annotated. Kind of disproves thermite being used huh? There's a whole site and PDFs that discuss how thermal expansion and fires caused the WTC7 to collapse. Terral is making shit up in his own theory which is why he won't answer any of my questions in the other thread he made.