Amanda Angelika wrote:

In news:1151394518.557162.174840@y41g2000cwy.googlegroups.com,
houlepn@attglobal.net <houlepn@attglobal.net> typed:

BornN2BS wrote:

The difference between heat and temperature is no more relevant than
the relationship between pressure and temperature where the 9/11
tragedy is concerned. It does, however, serve as another tool of
distraction for those who wish to clog the airways with obscure
prychobabble. Why do you choose to ignore the issue Mr. Graffiti. How
about we just get down to business here. (1) question: WHAT IS THE
MELTING POINT OF STEEL? answer: 2000 degrees farenheit. (2) question:
WHAT CAUSED THE STEEL INFRASTRUCTURE TO FAIL. answer:
??????????????????

Steel would lose half its strength at a temperature of 650C (1200F).

A gas cooker flame is around 800C. These flames regularly come into contact
with Steel, Copper and aluminium cookware for sustained periods without
having any adverse affect on the metal at all.

First, cookware is not under much stress. It does not have the
task if maintaining the integrity of a large building. It just sits
there
on the stove with the possible stress load incurred from the weight
of a mushroom omelet.

Second, a candle flame (paraffin) burns at roughly 1700C and yet
you can  move your finger through it and barely feel the heat.
Also, you can walk on a hot bed of coal up to 850C and not get
any burn. This is because the heat transfer is slow enough that
the temperature of your skin does not rise much.

Cookware on the gas stove gets heat pumped into it from the
hot flame that gets quickly dissipated away from it and then
radiated in the room or transferred to the food -- cooking
it and evaporating water. Metals conduct heat very well.

However hold a thin thread of steel (get it from a steel wool
pad), iron, copper, aluminium, etc. over the flame of a candle
and notice that it burns in less than a second. That is because
the thread being very thin in proportion to the flame, it is engulfed
in it and it can not efficiently conduct heat away. Its temperature
rises quickly to the melting and even the burning point. But put
cookware over the same candle and you can hardly get it to
reach 100C and boil a small puddle of water.

The same thing happens with steel in a fire. When the fire is
localized, steel beams dissipate the heat away and they do not
grow very hot. When the fire gets bigger, heat gets pumped at
a higher rate into greater lengths of the steel beams and they
do not dissipate it as efficiently. The temperature rises to
dangerous levels. See what sorts of empirical tests are
being conducted to get at the 600C-650C figures that I
mentioned :

http://irc.nrc-cnrc.gc.ca/pubs/fulltext/nrcc46290/nrcc46290.pdf

Note that three different common steel stud wall designs bearing
loads at or below specification failed when they reached
temperatures of 550C, 800C and 650C. Yet, these walls were
initially structurally intact. The WTC structures were already
severely damaged from the plane impacts.

The steel used in the construction of the WTCs was a special
steel with a higher melting point than ordinary steel somewhere
around 3000C.

What is your source for this?

Some forms of steel actually gets stronger when
heated.

That seems unlikely. What is your source? Tempered steel
that has been heated in the process of manufacturing it is hard
but it is also fragile. Could this be what you were thinking of?
Structural beams are never tempered. This would make them
too fragile. They would snap rather than bend under stress.

Its possible 650C would have no affect whatsoever on
the strength of some forms of steel. Indeed if those sort of
temperatures adversely affected steel to the extent you claim it
would not be possible to run a IC engine on Gasoline/Petroleum without the
cylinder block imploding. LOL

There is a maximally efficient management of the heat in
the Carnot cycle. Well oiled engine blocks do no get
close to the temperature of the burning fuel. The heat
produced is mostly converted in mechanical energy to
move your car forward. And even if they did grow hot,
they do not have to bear weight like structural
steel beams do. Just like your average cookware,
engine blocks are underloaded.