From 'Sudden Building Collapse: An Evaluation of a New Risk in Operational Fire-fighting' written by Paul Kayley of Firefighters for 9/11 Truth.
"The fires in Building 7 are reported by NIST to have started in the building shortly after the second tower came down at 10:28am. The official report states that falling debris from the second tower’s collapse ignited the fires.
The building was not hit by an aircraft. It did incur some damage to its south face from falling debris from the disintegration of the north tower but this is not the reason provided for the eventual collapse of the building many hours later.
According to NIST, the fires were said to be on floors 7-13, excluding floor 10, plus a couple of higher floors.
The debris, which is blamed for starting the fires, fell at 10:28am. However, the starting time of the fires is contradicted by a number of witnesses. Barry Jennings and Michael Hess were trapped in the building that morning and reported thick smoke, a lot of heat, and an explosion
sometime close to 9:30am, which is before the second tower collapsed and the falling debris. NIST disregarded these reports. The fire alarm control center also registered a “fire condition” on its system for Building 7 at 10:00:52am (NIST, NCSTAR 1-9, WTC Investigation, p.69.), but NIST decided this was most likely due to dust from the collapse of the first tower at 9:58am. The first
photographic evidence of fires from the outside of Building 7 wasn't until 12:15pm.
By NIST’s own accounts, “there was no evidence of floor-to-floor fire spread.” (NIST NCSTAR 1-9: 341.) This means that the explained source of ignition, falling debris, managed to ignite fires on ten floors, in an environment consisting of large amounts of suffocating gypsum and concrete powder which was coating all surfaces. This is not entirely impossible, but would best be described as being improbable rather than a probable cause of ignition. Once ignited, these fires managed to spread north through the building against a brisk north-westerly wind. To NIST’s
credit, they did admit that the idea that the fires were ignited by debris from the North Tower as only being a “likely” cause (NIST NCSTAR 1A: 16.). The two adjacent buildings, Verizon building, and U.S. Post Office did not experience any fire ignition, even though they too incurred significant damage from the falling debris of the North Tower.
Under all the aforementioned circumstances of multiple successful seats of fire igniting and developing against the odds and earlier witness reports of “thick smoke” within the building, a fire investigation officer tasked with establishing the true cause of this fire, would not eliminate arson as a possible cause.
There have been previously misplaced beliefs that the entire south face of Building 7 was on fire, probably due to the amount of smoke that was issuing from that side. It was indeed engulfed in smoke and there is a good reason for that. The wind was travelling predominantly from the north-west. Most of the windows on the north, east, and west faces were intact. The fires inside the building on the previously specified floors were obviously producing smoke. Hot fire gases travel up and into areas of lower air pressure via the most well-ventilated route. In the case of Building 7 the smoke from its fires was traveling up and out through the damaged and open south face into the negative air pressure created by the north-westerly wind. This does not mean that the whole of that face was on fire. As the NIST report confirms, fires were confined to a limited number of floors.
Information from witness testimonies, film footage, and photographs identify that the fires were small in number relative to the overall size of the building and involved only normal office contents. Initially, in the investigation it was suspected that diesel fuel stores for generators might have contributed to the fires, however, NIST’s final report states that “fuel oil fires did not play a role in the collapse of WTC 7.” (NIST NCSTAR 1A: xxxvi.)
An independent Fire Protection Engineer, Scott Grainger, studied the fires and reported them to be scattered and travelling, as they searched for new fuel when existing areas burned out. In his opinion, the fires would have only had sufficient fuel to remain in any one area for no longer than an hour.
In their description of the fires, NIST states that “WTC 7 endured fires for almost seven hours”, “the fires burned for sufficient time to cause significant distortion and/or failure to the building structure” and repeatedly reaffirms that the fires were “long lasting and uncontrolled”.
A person reading their report with no understanding of actual fire travel might easily believe that static locations within WTC7 were subjected to 7 hours of stress from uncontrolled fires. However, it is impossible for a fire to exist in one location for a period greater than the length of time taken for the fuel in that area to burn away. As NIST rightly points out, the fuel for the fires was ordinary office combustibles at ordinary combustible load levels, there was no use of accelerants, and the spread of fire from combustible to combustible was governed by ordinary fire physics.
On a number of occasions within the official report, the described fires do not match with the photographic evidence. For example, the fires on the 12th floor are observed photographically to have extinguished by 3:40pm yet are reported by NIST in their fire simulation graphics to be highly active between 4:00 pm and 5:00 pm.
Normal office fires, under the circumstances reported at WTC7, would have moved organically, following normal fire spread patterns from the exhausted fuel source to fresh fuel sources where possible, therefore staying fully developed in one area for only approximately 30 to 40 minutes at most. NIST openly admit this fact themselves, in fact, they are less generous and cite fires only being able to persist for between 15-30 minutes (Ref1 and Ref2). As documentation indicates, WTC7 had 3-hour fire resistance ratings for the columns and 2-hour fire resistance ratings for the floor assemblies (FEMA 2002).
In agreement with historical evidence of much more aggressive and prolonged fires in similar buildings, the reported and observed extent of the fire at this incident should not have compromised the structural integrity of Building 7, and certainly not to such an extent that the building’s complete failure would be realistically anticipated.
However, NIST is very confident that fire, and fire alone, was the cause of the building’s failure. “Even without the structural damage, WTC7 would have collapsed from the fires that the debris initiated.”-NIST
NIST’s explanation for WTC7’s unique collapse due to fire is blamed primarily upon poor water supply for the sprinkler system and fire-fighting operations. When comparing WTC7 with other similar structures involved in fires it states, “While the fires in the other buildings were actively fought by firefighters to the extent possible, in WTC 7, no efforts were made to fight the fires because of the lack of a water supply.”