Exactly correct except for the insulation on the steel beams...there wasn't any that was fireproof. It was for protection against condensation forming and causing water damage. IOW there wasn't any on internal beams of any sort but there was some on external beams... albeit not flame retardant.
And where most of the materials in the building weren't combustible the jet fuel in the airplanes most definitely was.
I assume by water damage you are suggesting that the water damage, from condensation, would be corrosion which would weaken the structural integrity of the building. The floor trusses are a much lighter member than what a steel beam would have been if it had been used. The trusses were used to reduce the dead load on the building columns.
The spray on covering to protect the trusses from corrosion also acts as a thermal retardant in a fire to slow down the rate of temperature increase of the steel trusses so that there is a safety time provided to evacuate the towers in the case of a fire. The Ultimate Tensile Strength of steel is halved when steel reaches a temperature around 600°C such that the load carrying ability of the steel structure is drastically reduced and failure is the outcome that the trusses will experience.
Any compromised protective covering of the steel trusses is a an area where the UTS of the truss structure will be compromised and the truss will likely fail at. The following link explains impact on the properties of steel at elevated temperatures: -
Temperature Effects on Metals Strength (tubingchina.com)
In the fire that resulted from plane fuel, the hottest area of the fire was around the outer shell of the building and the weak points for the building structure are the bolted connection of the floor trusses to the outer skin columns and the higher temperatures because of the available oxygen from the outside of the building would have cause the bolt there to fail from creep initially and since the bolted connections would have been torqued to 80-95% of their UTS, these connections were vulnerable to failure which would have caused the floors to fall unto the floor below.
The energy of the floor above falling onto the floor below would have been enough to cause the bolted floor connections to fail under shear because of the impact loads generated by the floor above falling onto the floor below. As the floors began to fall, the slenderness ration of the outer columns would have rapidly increased and they would have failed due to the buckling of each individual column because of the load of the floors above.
With the impact of falling material from the twin towers landing on the top of building seven, this would have been enough to cause the top level bolted connections to shear and as such, as the top floors began to fail because of the falling debris the pancaking of build 7 also began causing building 7 to also collapse in a similar manner like the two twin towers.
To the "novice" observer with a very limited understanding of structural steel building engineering principles, it is very easy to associate the loud "bangs" of the bolts shearing under the impact of the building floors above it falling onto that floor, as an explosion as the coincidence of the bolts shearing and the building collapsing would have happened at the same time by observation and their conclusion that the building had been rigged will explosive charges to collapse in a similar manner to what they have observed occurring during the deliberate demolition of buildings with explosives that has been shown on television numerous times.
Ignorance is a wonderful means to explain what they believe that they saw during the collapse of the WTC TT on 9/11.
A little like the understanding of many Christians when they read the scriptures, they come to many conclusions like the conspiracy theorists do, many of which are very wrong.
Shalom
