The story...

The [Madrid] Windsor Building was of a similar truss design to the twin towers, the fire started 11 storeys from the top of the building, and it burned at temperatures of 800ºC for more than 18 hours [AFP]. The core of the building did not fail.

The fire in WTC 1 is reported to have burned at 800ºC and was located roughly 17 storeys from the top of the building meaning the inner core supported only 6 additional floors of weight above the fire zone in comparison to the Windsor Building. WTC 1 collapsed after only 85 minutes, reportedly through core failure.

Don't you find this odd?
http://www.whatreallyhappened.com/wtc1_core.html

Our take...

The Madrid Windsor fire is sometimes cited as being relevant to the WTC collapse, but in reality there are major differences between the two situations.

No plane flew into the Madrid Windsor Tower, for instance. It didn't sustain any structural damage prior to the fire beginning. (And for those who keep emailing us to say that neither did WTC7, reports of the damage there are covered here.)

The Madrid Windsor Tower was much smaller than the WTC, too, at 32 storeys. 

More significantly, the design of the Madrid Windsor Tower was entirely different to that of the WTC.

The building totalled 32 storeys, with 29 floors above ground and three below. A concrete core and concrete frame supported the first 16 floors. Above that was a central support system of concrete columns, supporting concrete floors with steel perimeter columns. An additional feature was the presence of two 'technical floors' - concrete floors designed to give the building more strength. One was just above the ground level and the other at the 17th floor.
http://www.concretecentre.com/main.asp?page=1095

No reliance on steel frames here, the core was mostly concrete. And what happened to the steel that it did include?

The steel columns above the 17th floor suffered complete collapse, partially coming to rest on the upper technical floor.
http://www.concretecentre.com/main.asp?page=1095

Yes, it failed. Other photos reveal how the concrete was all that was left on the upper floors.



The same story suggests it’s only the key design differences from the WTC that kept the Madrid Windsor Tower standing.

An investigation is underway between Spanish technical agency Intemac and UK authorities including Arup Fire, the University of Edinburgh and the concrete industry including Cembureau, BCA and The Concrete Centre. Preliminary findings suggest that a combination of the upper technical floor and the excellent passive fire resistance of the tower's concrete columns and core prevented total building collapse

The fire is significant in terms of its potential similarities between the collapse of the building's steel frame above the 17th floor and the experience seen at the World Trade Center. Notably, one of the recommendations of NIST's interim report on the World Trade Center disaster is for tall building design to incorporate 'strong points' within the frame.
http://www.concretecentre.com/main.asp?page=1095

Others confirm the advantages offered by the Windsor Tower design.

Dr. Pal Chana of the British Cement Association demonstrated the relative likelihood of floor collapse in a steel versus concrete framed building, using the vivid example of the Madrid Windsor Tower fire which raged over 26 hours on 14-15 February 2005. This former landmark office block of 30 storeys featured a concrete core throughout, but with concrete columns up to the 21st floor and steel columns between the 22nd and 30th floors. Remarkably, despite the intensity and duration of the fire, the concrete floors and columns remained intact however, the steel supported floors above the 21st floor collapsed, leaving the concrete core in-situ and exposed.
http://www.concretefireforum.org.uk/main.asp?page=0

So what does the Madrid Windsor Tower fire show? That steel columns will collapse in a fire, that concrete is more fire-resistant, and, uh, that’s about it. It’s hard to see how any of this, especially in such a different building design, can have much meaning for the WTC case.