Nice video, Dave!
I have some criticism though:
You burned elemental steel. Yes, that's a way to create iron-rich microspheres, but I don't know that anyone has a theory about such spheres at GZ that would involve the burning of elemental iron. There is a reason why you picked steel wool: Because it is such a thin material. Which steel at the WTC would have been as fine yet close to elemental?
Metal fires can get a lot hotter that organic combustibles, on account of their oxides not being gaseous. You did not determine the temperature of the flame when you burned your sample. How can you be so sure it's only like 700°C?
At 6:23, you commit a blunder, a false statement: "...spheres were indeed pure
iron". Urr say what? I see a big peak for O in the XEDS graph, and uhm didn't you burn - oxidize
- that stuff? I am pretty sure you are not looking at pure
(elemental) iron in those spheres but iron oxide
At 7:47, you claim that the office fires got a lot hotter than a BIC lighter flame. I believe this is wrong. Check out http://en.wikipedia.org/wiki/Gas_flame
Gas flames can burn up to 1500°C (methane) - 1700°C (propane).
All kinds of numbers abound on teh interwebz about the actual temp of ordinary lighters. The english Wikipedia
has storm lighters "in excess of 1100°C", the French
goes even to 1200-1500°C.
Just look at your BIC flame: It appears blueish at its base, indicating an oxygen-rich, hot flame. That would be much hotter than most flames in room fires.
Your conclusion is of course correct: Iron-rich spheres are not indicative of exotic. high-tech incendiaries and malicious intent, but can be produced under quite mundane conditions and are not as such proof of anything.
I still don't see though that we know real well where the iron-rich spheres that for example RJ Lee reported came from. Not from steel wool, that's for sure.
I suspect that such spheres are not normally formed from elemental iron, but from
a) combustion of chemical compounds that contain iron atoms (Myriad explained that this happens in ordinary wood fires, though I know no mass proportions)
b) Heating of very small particles of irom oxides, such as pigments, in orgamnic matrix (paint!)
c) Were present in the buildings to start with, e.g. in the flyash portion of lightweight concrete
If someone could show that the burning of flaked-off steel primer (the epoxy therein, for example) made the adhering iron oxide condense to spheres, that would be swell...