Wow... this thread has been busy...
I'll add my two cents
On the matter of the cars...
For whatever reason, in my line of work I have had the experience of setting alight quite a few cars.
I can say with conviction that the fires produced are incredibly unpredictable, as is the resultant damage.
Nothing about the pictures of car fires I have seen seems odd or unlikely to me.
For anyone who does find them odd, I would respectfully suggest they do not have any experience with witnessing car fires.
Onto the collapse mechanism of the towers...
NIST has often cited the loss of fireproofing as a primary factor in the collapse. Severed columns alone would not have produced collapse. Neither would resulting fires.
It was the stripping of the fire proofing that exposed the steel to fatal heat. Someone has linked to a NIST test that demonstrates how well the steel would have resisted collapse had fireproofing been in place.
What hasn't been mentioned is the NIST tests on unprotected steel from the WTC. They found the steel lost critical strength in 20 minutes of flame exposure.
Likewise, the Kader Toy Factory (the world's worst industrial fire), with an unprotected steel frame, collapsed in 15 minutes.
The dislodging of fireproofing is vital in the collapse mechanism.
So.
Are NIST making it up? No. To suggest they are, to me, clearly indicates the person making the claim has not read the NIST report. I did read it. Their report includes pages and pages of photographs of the burning towers, with clearly identifiable exposed steel where the fireproofing had been removed.
(The steel was coated with a dull red primer paint which is easily identifiable in the photographs).
NIST estimate, from extensive photographic evidence, that the removal of fireproofing was extensive and ultimately was what brought the towers down.
Lastly, we have the "extent of the fires" argument.
The 78th Floor fires are cited. First, let's learn a little about what happened on the 78th floor.
As some know, people began evacuating WTC2 when WTC1 was hit. When it was announced WTC2 was safe, some decided to return to their offices. Others continued to evacuate. As you can imagine, the elevators would have been busy.
The 78th floor is one of the sky lobbies. As such, at this moment it was crowded with people. When UA175 hit the WTC the wingtip slammed into the 78th Floor, killing an estimated 50 - 200 people instantly.
How do we know this?
Because people who were waiting for those same elevators on that same floor survived. They lived to tell off the carnage and destruction that occured on that floor.
Of course, fire was not the primary killer. The fuel tanks on a 767 don't extend to the wingtips. And a skylobby does not have as much furniture as other floors. If any jet fuel did find its way into the 78th floor, it would have had little fuel to spread to.
This is in contrast to the upper floors. In a modern office a high percentage of material is made from hydrocarbons. Carpet, furniture, pens, folders, computers, all synthetic. All hydrocarbons. All rich fuel for a hungry fire.
What other evidence is there of the heat?
Well, there's the NYPD helicopter, for a start.
After the 93 WTC bombing, many people were rescued by helicopter from the roof of the building.
On 9/11 the heat coming off the top of the buildings was so severe the NYPD police helicopter could not get near the roof as the engine on their aircraft would overheat.
Later, some short time before collapse, the NYPD police helicopter reported the steel in the building was glowing "red hot".
Not an extensive fire?
Indeed.
-Gumboot
