Aluminum/magnesium Alloys Options

[Bill Duke]

Hello...First time posting on this forum. Following, you will find a post from 7/6/08's CD article about WTC 7 and the new NIST report. Since I am not a metalurgist or a chemical engineer of any sort, I yield to anyone on this site who may have an eplanation. The contention is that the 747's body parts are composed of an aluminum/magnesium alloy that under conditions of proper combustion as in the crashes at the WTC, become highly flammable and reach temps of 4000 degrees. Here's the post....any feedback will be greatly appreciated...



Hi ~GDE~. I was an aircraft crash investigaor and worked directly for the SAC IG for five years. Crash investigations are always conducted when the cause of an aircraft crash is “not known”. There were very few pieces of aircraft left to investigate at the crash site of the WTC. Just a few scraps.

In addition, video evidence of exactly how the crashes occurred was readily available and there was no doubt as to the cause of the crashes.

Another person asked about melting steel, as burning jet fuel will not melt steel. That is true\, it will cause stteel to warp or bend out of shape after an hour of fire. What is also true is, aircraft aluminum is a mixture of aluminum and MAGNESIUM and it will burn at temps approaching 4,000 degrees, which is more than hot enough to melt steel beams.

The two aircraft were almost fully loaded with tons of fuel, which exploded on impact and the resulting fires were not accessable to firemen and auto sprinkers on those floors were wiped out by the crashes and they wouldn’t have helped with a fuel and magnesium fire anyway. No firemen ever got onto the floors where the aircraft entered.

There were tons of “smushed”, into a compacted mass of burning aircraft, wedged right up into the buildings central cores. The heat would have been near 4,000 degrees at those locations. That is where the building floors were attached, and the heat went right up the center of the buildings, like giant chimneys.

There are also some other aircraft parts, such as the large landing gear wheels, which are solid magnesium, and once magnesium, or magnesium aluminum alloys are afire, they cannot be put out, except by burying them in sand or smothering with foam. Water on magnesium fires will cause it to explode.

Military aircraft generally have more magnesium than commercial airliners, but there was tons of magnesium in those 767s which struck the two towers. Later mdels ahve less magnesium. A fact which has been ignored in all of the official reports about the 9-11 disaster. It should not have been ignored.

[dMz]

Hello and welcome BD (we already have a Bill here),

One thing- most of us here are pretty "jaded" at this point due to months or years of dealing with online disinformation- we like to see a link to information that we can inspect firsthand. I detect a couple of indicators of "spin" and "appeal to 'expert' authority" in the above quoted information IMHO. There is a general statement about magnesium and aircraft alloys without any supporting sources of information...

According to:

http://www.ccohs.ca/oshanswers/chemicals/c...orking_alu.html

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"Reactive flammable solid. Bulk aluminum powder or dust in contact with water may heat spontaneously. Moist, finely divided aluminum powder may ignite in air, with the formation of flammable hydrogen gas. The hazard increases as the aluminum particle size decreases. Contact of burning aluminum with water forms flammable hydrogen gas, an extremely dangerous explosion hazard, particularly if the fire is in a confined area. Bulk aluminum metal itself is not combustible.

Under certain conditions, a dust cloud of aluminum powder can explode when ignited by a spark or flame. When evaluating the explosion hazard of a specific process or sample of material, the important factors to consider include: particle size and shape, dust concentration, the nature of any impurities, oxygen concentration, humidity, and extent of containment. Explosions of aluminum dusts have occurred in industry.

IGNITION SENSITIVITY: 1.4 (aluminum, atomized); 7.3 (aluminum, flake)

EXPLOSION SEVERITY: 7.7 (aluminum, atomized); 10.2 (aluminum, flake)

The EXPLOSIBILITY INDEX is greater than 10 for both atomized and flake aluminum. This value indicates that a "severe" explosion could occur. This hazard rating index is calculated by multiplying the ignition sensitivity (ignition temperature, concentration, etc.) and the explosion severity (explosion pressure, rate of pressure rise).

MINIMUM IGNITION TEMPERATURE: 650 deg C (1202 deg F) (cloud); 760 deg C (1400 deg F) (layer) (aluminum, atomized); 610 deg C (1130 deg F) (cloud); 320-326 deg C (608-619 deg F) (layer) (aluminum, flake); 420 deg C (788 deg F) (aluminum, 6 µm)

MINIMUM CLOUD IGNITION ENERGY: 50 millijoules (mJ) (aluminum, atomized); 10 mJ (aluminum, flake); 13 mJ (aluminum, 6 µm); 28 mJ (aluminum, 17 µm)

MAXIMUM EXPLOSION PRESSURE: 579.2 kPa (84 psi) (aluminum, atomized); 875.7 kPa (127 psi or 8.8 bar) (aluminum, flake); 640 kPa (6.4 bar) (aluminum, 6 µm); 700 kPa (7.0 bar) (aluminum, 17 µm); 540 kPa (5.4 bar) (aluminum, 100 µm)

MAXIMUM RATE OF PRESSURE RISE: Greater than 138000 kPa/sec (greater than 20000 psi/sec or 1380 bar/sec) (aluminum, atomized and flake); 133100 kPa/sec (1331 bar/sec) (aluminum, 6 µm); 62100 kPa/sec (621 bar/sec) (aluminum, 17 µm); 13500 kPa/sec (135 bar/sec) (aluminum, 100 µm) "
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Unless this was a "finely powdered" or "atomized" Boeing 767-200, I don't afford much credibility to the "burning Al/Mg" theory. Also, I think aircraft are entirely irrelevant in discussions about WTC7, since it was never struck by aircraft.

Okay, on to Jet A fuel. There is a recent discussion here at:
http://pilotsfor911truth.org/forum//index....&p=10746044

The important part is "open air burning temperatures: 287.5 °C (549.5 °F)" for Jet A fuel. This is considerably lower than 420 C, so Jet A should not be able to ignite a cloud of 6 micro-meter aluminum "vapor" in a normally-aspirated fire (combustion or oxidation reaction).

Oh yes, I'm a scientist/engineer and am not exactly a stranger to metallurgy, materials science, chemistry, physics, etc.

Hope this helps,
d

EDIT: I think you and Oceans' are referring to the late Chief Orio Palmer.

http://www.wnyc.org/news/articles/7869