jaydeehess
Penultimate Amazing
,,, and automobiles in the garage areas, and transformers with their oil supply etc.. In point of fact Chris, your arguement seems to be that there is not enough combustible material in an office building to support a large fire. That is shown to be incorrect in that office fires do occur just fine with the amount of fuel available. The ratio of non-combustibles to combustibles remains the same in a building that has been destroyed as it was when the building stood.
The combustible material has also been shredded which would increase its ratio of surface area to volume meaning that more material can be presented to an available oxygen supply and thus burn more efficiantly.
BTW has anyone here actrually argued that any material burns hotter in low oxygen than in high oxygen. Fact is that the flame itself will always be at the same temp. If a specific reaction requires oxygen and s exothermic then it will aways release the same amount of heat. All that changes in a well ventilated situation is that more material is undergoing that reaction AND the air entering the combustion is taking heat away. By forcing air in you aloow more material to burn at the same time thus increasing the amount of heat produced which is then relaesed to the surroundings. So to increase the temp one can burn more stuff(ie increase the oxygen supply) or decrease the ability of the surroundings to take that heat away. In a room in which there is a fire and if one then slows the oxygen supply less material will now be burning BUT since the room(or woodstove for that matter) still can transfer heat away as well as it could before and so the room cools.
Take the same situation and as you slow the oxygen supply also blanket the room with an greater insulation and the room will cool slower and never get as cool as it would have without adding that insulation.
Insulate a woodstove enough and you will easily reach the point where the steel is red hot even if you restrict the airflow. (of course also restrict chimney size to allow gasses to exit only as fast as oxygen is entering the system so as to again decrease the hat loss.)
Specious arguement. An unventilated anything in which one means absolutly no oxygen supply means no fire and thus no heat being produced and thus the temperature of that room will depend soley on its heat loss by convection and radiation.
Why would a debris pile have "less air than in an unventilated room"? You still have not made that arguement stick Chris. Obviously there were some voids in the pile as people were found in the debris. You say they were on near the surface buit you also state that the pile was covered by concrete that had been reduced to gravel or smaller chunks as well as all office material reduced to chunks no bigger than a telephone. That would preclude any survivors at all, anywhere in the debris pile. In fact all survivors were people who were near the ground level when collapse started so 110 stories of debris came down around them. It has been pointed out that the subway allowed a way for air to enter, the hollow columns allow a way for air to enter[/quote]
What?? bunk beds??
As air came to a fire face it would burn only that material of the surface area it came in contact with. It would release heat and expanding gases. The heat is absorbed by the surrounding mass. The material burns through and the air supply follows the opening passage created by the smaller volume of materail as it is consumed in the fire and at the same time the heat being produced is not escaping readily thus the nearby volume heats up. Now the fire is more efficient as the material about to be burned is already close to or even at, its ignition temp when it gets oxygen.
You now have a situation in which much of the surrounding non-combustible amterial can reach a temp where it glows red hot. If aluminum or copper is present it can reach its melting point and become liquid. Steel and iron deform under any strain, torgue or tension as it has lost much of its strength.
Thermite requires no oxygen, it reacts rapidly, very rapidly, and even a large amount will be gone within minutes releasing a very large amount of heat in a very localised volume. It will chew through steel and spall concrete and fireball of such a large mass will head for the center of the earth creating something that will resemble a small volcanic pipe. It will not do what was seen to occur in the debris pile where the fire travelled around the pile.
