The 9/11 WTC fires - where's the inferno?

The official reason given for the collapse of the twin towers is structural failures occurred on the impacted floors due to infernos of 800ºC+.

Image Source: BBC

Not everyone is convinced by the official story of the towers collapse...

The laboratory director from a South Bend firm has been fired for attempting to cast doubt on the federal investigation into what caused the World Trade Center's twin towers to collapse on Sept. 11, 2001. Kevin R. Ryan was terminated Tuesday from his job at Environmental Health Laboratories Inc., a subsidiary of Underwriters Laboratories Inc., the consumer-product safety testing giant.

Ryan wrote that the institute's preliminary reports suggest the WTC's supports were probably exposed to fires no hotter than 500 degrees -- only half the 1,100-degree temperature needed to forge steel, Ryan said. That's also much cooler, he wrote, than the 3,000 degrees needed to melt bare steel with no fire-proofing.

"This story just does not add up," Ryan wrote in his e-mail to Frank Gayle, deputy chief of the institute's metallurgy division, who is playing a prominent role in the agency investigation. "If steel from those buildings did soften or melt, I'm sure we can all agree that this was certainly not due to jet fuel fires of any kind, let alone the briefly burning fires in those towers." [Salt Bend Tribune]

WTC 1

Eyewitness testimony and video evidence document no inferno at the aircraft impact level

WTC 2

Survivor testimony and firefighters transmissions document no inferno at the aircraft impact level

"It was noticeable that with the South Tower, the one that fell first, the ensuing ash was white and grey, whereas with the second tower that fell, the North Tower, it was black. Now, if that was because it burned longer or what I don't know, but it was a noticeable difference." [Nova Online]

This observation along with the above indicates two things:

There was little fire in WTC 2 prior to its collapse.
The black ash from WTC 1 indicates the presence of large amounts of soot. Soot is a byproduct of inefficient combustion, therefore the fires in WTC 1 did not burn at extreme temperatures.

9/11 Comparison Fires

October 2004

Venezuela

Fire duration:
17 hours

February 2005

Spain

Fire duration:
20+ hours

Both of the above buildings were of inferior build quality to the WTC, yet they burned hotter & far longer than the twin towers & WTC 7 AND REMAINED STANDING.

WTCs 1 & 2

WTC 2 fire duration:
56 minutes

WTC 1 fire duration:
85 minutes

WTC 7

No aircraft impact

Fire duration:
6 hours

The "truss theory" relies on the assumption that 800ºC+ infernos started a catastrophic chain of events which led to the collapse of the twin towers. There were fires in both buildings following the aircraft impacts, but no infernos - "most perimeter panels (157 of 160) saw no temperatures above 250ºC."

Engineers say heavy insulation protected the steel frames of the buildings [...]. They say that automatic sprinklers and firefighters probably could have extinguished the fires had they been fed by typical office contents desks, carpets and paper. [Birmingham Business Journal]

The fires were indeed fed by typical office contents, so the buildings should have remained standing.

They didn't.

Why?