Leading Hypotheses for the Collapses of the World Trade Center Towers

[LARED]

http://www.nist.gov/public_affairs/releases/wtc_latest_findings_1004.htm

WTC 1

Aircraft impact damaged the perimeter columns, mainly on the north face, resulting in redistribution of column loads, mostly to the adjacent perimeter columns and to a lesser extent, the core columns.

After breaching the building’s perimeter, the aircraft continued to penetrate into the building, damaging floor framing, core columns and fireproofing. Loads on the damaged columns were redistributed to other intact core and perimeter columns mostly via the floor systems and to a lesser extent, via the hat truss (the steel structure that supported the antenna atop the towers and was connected to the core and perimeter columns).

The subsequent fires, influenced by the impact-damaged condition of the fireproofing:

Softened and buckled the core columns and caused them to shorten, resulting in a downward displacement of the core relative to the perimeter. This led to the floors (1) pulling the perimeter columns inward, and (2) transferring vertical loads to the perimeter columns; and

Softened the perimeter columns on the south face and also caused perimeter column loads to increase significantly due to restrained thermal expansion.

Due to the combined effects of heating on the core and perimeter columns, the south perimeter wall bowed inward and highly stressed sections buckled.

The section of the building above the impact zone began tilting to the south as the bowed south perimeter columns buckled. The instability rapidly progressed horizontally across the entire south face and then across the adjacent east and west faces.

The change in potential energy due to the downward movement of the building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse then ensued.

WTC 2

Aircraft impact damaged the perimeter columns, mainly on the south face, resulting in redistribution of column loads, mostly to the adjacent perimeter columns and to a lesser extent, the core columns.

After breaching the building’s perimeter, the aircraft continued to penetrate into the building, damaging floor framing, core columns and fireproofing. Loads on the damaged columns were redistributed to other intact core and perimeter columns mostly via the floor systems and to a lesser extent, via the hat truss.

The subsequent fires, influenced by the impact-damaged condition of the fireproofing:

Caused significant sagging of the floors on the east side that induced the floors to pull the perimeter columns inward on the east face;
Softened and buckled the core columns on the east side and caused them to shorten, which transferred significant additional load to the perimeter columns on the east face primarily through the floor system and to a lesser extent, the hat truss; and
Softened some of the perimeter columns that were exposed to high temperatures toward the northern half of the east face.

Due to the additional loads on the perimeter columns on the east face and the inward pulling of those columns, the east perimeter wall bowed inward and highly stressed sections buckled.

The section of the building above the impact zone began tilting to the east and south as both the east perimeter columns and the impact-damaged south perimeter columns buckled. The instability rapidly progressed horizontally across both faces and across the north face.

The change in potential energy due to the downward movement of the building mass above the buckled columns exceeded the strain energy that could be absorbed by the structure. Global collapse then ensued.

[RC]

1. B.S.

The building were designed to take an impact like this. Both building collapse into their own foot print, even though they were hit differently?
Also the 2nd hit was through a corner of the building, thereby missing all or most of the main building support.
The fire has long since been debunked as burning hot enough to soften the supporting steel.

[MrSammo1]

36. Notice.....

How the potential energy of the bottom floors is basically thrown out the window? The structural integrity of all that steel.........is simple thrown away!

New Sheeple Science lesson!

It is now possible to move huge masses with much smaller ones!

http://www.walter-fendt.de/ph11e/ncradle.htm

[RH]

43. The Towers had never stood still

They moved. They swayed in the wind.

The ability of a tall building to stand up depends upon its ability to damp its own vibration. It is a persistent architectural problem. When a building's ability to damp its own vibration is insufficient it tends to fall down and that ability depends more on what is happening at the top of the building.

This was all explained by Oud Van Dagen on previous DU threads.

[peacetalksforall]

2. NIST- National Institute of Science and Technology /U.S. Government

I'd like a second opinion.

[LARED]

3. Sure, there are plenty of opinion out there

Do a google search and you can thousands of "experts" in operating search engines that can tell you anything you want to know about 9/11. 99 percent of them are loons

Of course if you are interested in what professional people that actually know how to investigate these things have to say, the NIST reports are a good place to start.

[RC]

4. And while your are at it,

Show me the 100 ton plane in the Pentagon.

[LARED]

5. Tell you what

You stick with google trained engineers and scientist and I'll stick with the professionals.

[tngledwebb]

7. Whose and which

professionals do you STILL trust lared, in these stranger and stranger days? 9/11 skeptics as well as most Dems's certainly don't trust THIS govt's choice of 'professionals' whether civilian, military, investigative, or other, and, ipso facto, have a very hard time trusting those whose trust those 'professionals'.

[Name removed]

8. Deleted message

Message removed by moderator. Click here to review the message board rules.

[Name removed]

9. Deleted message

Message removed by moderator. Click here to review the message board rules.

[LARED]

10. Is there a point in there?

1. NIST report says nothing relevant and definitive.

I thought your argument was the NIST investigators are compromised in some fashion.


2.Who picked the committee? Do you know?

Do you know? Why would it matter? Do you think these folks are Bushco sympathizers? They seem like a pretty credible bunch to me.


The National Construction Safety Team Advisory Committee will advise the director of the National Institute of Standards and Technology on carrying out investigations of building failures conducted under the authorities of the NCST Act that became law in October 2002. That includes advice on the composition and function of investigation teams and other responsibilities under the Act.

The committee members are:

John M. Barsom
President, Barsom Consulting, Ltd, Pittsburgh, PA
Term Expires: March 31, 2005

From 1967 to 1998, Dr. Barsom worked at U.S. Steel Research Laboratory in Monroeville, Pennsylvania, where he was named a Research Fellow, the company’s highest technical position, and served as director of materials technology. He is a specialist in fracture mechanics, failure analysis of structures and equipment, accident reconstruction, integrity and life extension of structures and equipment, properties and behavior of steels and welds, and behavior of fabricated components under various loading conditions. Dr. Barsom has degrees in physics, mathematics, and mechanical engineering from the University of Pittsburgh.

David S. Collins
President, The Preview Group, Cincinnati, OH
Term Expires: March 31, 2007

Mr. Collins has 30 years experience in architectural practice, as a building code official, in building code and regulatory issues, and in the analysis of existing buildings. He is an active participant in building and fire code development organizations, including the International Code Council and the National Fire Protection Association. He also serves as manager of the codes advocacy program of the American Institute of Architects. Mr. Collins has degrees from Purdue University and the University of Cincinnati, and is a registered architect. Mr. Collins is a Fellow of the American Institute of Architects.

Glenn P. Corbett
Professor, Public Management-Fire Science, John Jay College of Criminal Justice, New York, NY
Term Expires: March 31, 2006

Professor Corbett has extensive experience in different facets of fire protection, including teaching fire science at the John Jay College of Criminal Justice and acting as administrator of engineering services at the San Antonio (Texas) Fire Department, as fire protection engineer at the Austin (Texas) Fire Department, and as loss prevention consultant at A.B.C. Loss and Fire Prevention Corp. (East Orange, New Jersey). He was an auxiliary firefighter at the Paterson (New Jersey) Fire Department and currently is First Captain at the Waldwick (New Jersey) Volunteer Fire Department. He has degrees from Worcester Polytechnic Institute and John Jay College of Criminal Justice.

Philip J. DiNenno
President, Hughes Associates, Inc., Baltimore, MD
Term Expires: March 31, 2005

At Hughes Associates, Mr. DiNenno is responsible for planning, executing, and analyzing fire protection design, research, and development projects. He also served as a fire protection engineer at Benjamin/Clarke Associates and Professional Loss Control Inc. He developed and taught a course on mathematical modeling of fire development and smoke movement at the University of Maryland. Mr. DiNenno has a degree in fire protection engineering from the University of Maryland.

Paul M. Fitzgerald
formerly Executive Vice President, FM Global, Johnston, RI
Term Expires: March 31, 2006

Currently residing in Holliston, Massachusetts, Mr. Fitzgerald has served in a wide variety of executive and technical positions at FM Global, one of the world’s largest commercial and industrial property insurance and risk management organizations specializing in property protection. Mr. Fitzgerald’s positions have included president and chief executive officer and chair of the board of directors for both Factory Mutual Engineering and Factory Mutual Research. He has degrees from Tufts University and Babson College.

Robert D. Hanson
University of Michigan, Professor Emeritus, Walnut Creek, CA
Term Expires: March 31, 2006

Dr. Hanson taught civil engineering at the University of Michigan for 18 years and was chair of the department for eight years. He has extensive experience as an expert in earthquake engineering and steel structures and an advisor to organizations such as the United Nations Educational, Scientific and Cultural Organization; International Institute for Seismology and Earthquake Engineering, Tokyo, Japan; and the Federal Emergency Management Agency. Dr. Hanson has degrees in civil engineering from the University of Minnesota and the California Institute of Technology. He is a member of the National Academy of Engineering.

Charles Thornton
Chairman and Principal, Thornton-Tomasetti, Inc., New York, NY
Term Expires: March 31, 2005

Dr. Thornton has overall responsibility for engineering, design, and research and development activities, as well as strategic planning. His 40 years of experience at the firm have included involvement in the design and construction of billions of dollars worth of projects in the U.S. and overseas, ranging from hospitals, arenas and high-rise buildings to airports, transportation facilities and special structure projects. Many of these projects have set industry standards for innovative thinking and creativity. In addition, he has extensive experience in conducting failure investigations. He has degrees in civil engineering from Manhattan College and New York University, and is a registered professional engineer in 14 states and the District of Columbia. Dr. Thornton is a member of the National Academy of Engineering.

Kathleen J. Tierney
Professor, Department of Sociology
Director, Natural Hazards Research and Applications Information Center, Institute of Behavioral Science, University of Colorado at Boulder
Term Expires: March 31, 2007

At the University of Colorado, Dr. Tierney holds a joint appointment in the Department of Sociology and the Institute of Behavioral Science. Her research and teaching interests include the sociology of disasters, environmental sociology, collective behavior and social movements, and qualitative research methods. She is the Director of the Natural Hazards Research and Applications Information center, which since 1976 has served as a national and international clearinghouse for information on hazards. Dr. Tierney’s other current and recent activities include service on the Project Management Committee for the FEMA/NIBS nationwide study on savings realized through disaster mitigation; co-authorship on the NEHRP plan for coordinating post-earthquake investigations; and membership on the Executive Committee of the Multidisciplinary Center for Earthquake Engineering Research and the Leadership Group of the Johns Hopkins University Center for Civilian Biodefense Strategies. She is a member of the American Sociological Association, the International Sociological Association, and the Earthquake Engineering Research Institute. Dr. Tierney has degrees in sociology from Youngstown State University and Ohio State University.

Forman A. Williams
Professor, Department of Mechanical and Aerospace Engineering, and
Director, Center for Energy Research, University of California at San Diego, CA
Term Expires: March 31, 2005

Dr. Williams has taught engineering physics and combustion at the University of California since 1988. Prior to 1988, he taught at many prestigious colleges and universities around the world, including California Institute of Technology, University of London, Harvard University, Universite de Provence, and Princeton University. Dr. Williams has degrees from Princeton University and the California Institute of Technology. He is a member of the National Academy of Engineering.


3.Name calling and stereotyping fellow DU'ers who don't agree with your OCT world view (many of whom have displayed considerable journalistic, analytical and investigative cajones, far above those content to quote from Officialdom) only undermines your own credibility.

Fellow Du'er? I have not meantioned one DU'er.

[tngledwebb]

11. Re the unanswered points I raised.

1. Show anything substantial in NIST report that shuts down this case...

2. Not what I asked you. Said- do YOU know these guys? What was their remit, who picked them etc. You aren't so naive as to be impressed by a long resume? PNAC members, yes even those evil ugly ratfink bastards have racked up some big-ass resumes, even the Bushbunny himself got an Ivy League degree.

3. You DIDN'T mean other DU'ers? You been spending even more time elsewhere looking at OTHER 9/11 skeptics websites? Links? Ie if you weren't referring to DU 9/11 skeptics and their sources and sites, how can anyone know what you are talking about?

[LARED]

12. Okee Dokee

1. Show anything substantial in NIST report that shuts down this case...

I long ago came to the conclusion that no amount of facts or investigation will ever shut down this case. The CT will just get bigger and bigger to accommodate any fact thrown at it.

I am not trying to close the case anyway. I was merely posting information about the ongoing investigation into the tower collapse. There is a group here that is interesting it the collapse.


2. Not what I asked you. Said- do YOU know these guys? What was their remit, who picked them etc.

I told you I don't know who picked them already. I asked you why it mattered? Well? Do you have any evidence that these people are in some way part of, or being used to cover up something? Do you?

[tngledwebb]

13. And also...

1. Right, no CONCLUSIONS from NIST yet, just keeping everybody up to date...ok.

2. And you have evidence to the contrary? Absolute integrity and honesty abounds in the scientific community, unlike the rest of professional world? Remember those tobacco experts a few years ago lying themselves blue on C-span? Corporations and our Govt got their shills and patsies all over the place, not a news flash.
Or, these experts are as honest as the day is long, but their remit is narrow, maybe only to explain how the event MIGHT have happened, and/or their evidence may have been incomplete, or not examined first-hand in every case, and/or most importantly, this Govt says some issues and areas are off limits in the interests of national security. Do you honestly believe that kind of scenario is impossible?

3. Links to other 9/11 skeptic sites you were referring to appreciated.

4. Btw I haven't alerted DU mods about your posts. Wonder why the deletions?

[RH]

21. Absolute integrity?

Absolute integrity is hardly the issue, is it?

Never mind absolute integrity. For the run of the mill 9/11 conspiracy theory to be believed you're in effect obliged to make out that hundreds if not thousands of relatively ordinary people are criminally complicit with regard to mass murder, hence the security of their homeland, or at least that they dont care who did it, or else they are just too stupid to think it through for themselves.

Where then is one to see evidence to that effect?

And in any case because of what is your opinion of this to be respected, let alone any preference?

[tngledwebb]

26. Wasn't asking you.

but you didn't answer the questions either. Remember, no surprises, no prizes. Try again tomorrow.

[tngledwebb]

25. You miss the point, again, quel surprise.

Or maybe not, but you've chosen not to give anything like an answer to the first question, and that speaks volumes. Interesting that you say you are NOT trying to close the case. How do you mean? Wouldn't you like to solve the biggest mass murder in history, or play a small part, or would you be happier to let all the questions hang in the air until next time? What are you doing HERE if not? Do you really not have any 9/11 questions?

As for 2. You DID miss the point, but if you take your time and re-read the post, it shouldn't be too taxing to find it, in light of how quickly you get through long and complex offical reports filled with bureaucrat-ese and psuedo-scientific lingo and still understand them far better than your fellow Du'ers could ever hope.

Still, and I am really somewhat chagrined to ask you a question I already know the answer to- Do you have any evidence they are NOT being used? Do You?

[LARED]

32. RE

Interesting that you say you are NOT trying to close the case. How do you mean? Wouldn't you like to solve the biggest mass murder in history, or play a small part,

The NIST is working on determining why the WTC's collapsed so future buildings will be safer. There are not working on solving a murder mystery that has been cooked up by a bunch of CT'ers. Lack of them addressing these fantasies is not evidence of anything other than common sense.


Do you have any evidence they are NOT being used?

Trying to prove a negative is pointless. It really stretches your credibility when you posture that this group of professionals are all somehow bought off by the government to hide evidence that the government killed 3000 citizens. I don't have any evidence that you do not have small children locked in the basement for evil purposes. Should I call the FBI because I don't have evidence that you have small children locked up.

The real issue is and will continue to be, do you have any evidence these people are being used. If not, move on to your next fantasy.

[peacetalksforall]

6. Yes, I'm waiting also - I might even get some tutoring if necessary to

read through it - the Pentagon report.

fyi: I love loons.

It takes a lot of opinions to set off more opinions - barnstorming sessions are a great tool.

If * can look into the soul of Putin and lead by his gut, I can say that within minutes of watching those buildings, my gut told me that it was explosives. One gut. faith, a lot of revenge and contempt, plus turned off ears are at the heart of our pRresident of the United States, so I can have a moment of gut to believe in it until convinced by people I can trust and I can express my disrespect for * and my caution about believing anything coming out about 9/11.

I'll believe in the government if they reopen the put options case. If anyone doesn't know - the case is closed - the investigation under John Ashcroft says there was no wrongdoing. But, I could read the statistics and know that they are supposed to have experts reading the market for indications of any kind of wrongdoing. And I've been told countless times that part of the profits, about 2.5 mil, has not been claimed. So, I am supposed to believe everything that comes from this regime?

Andwhileyou'reatit - I combined my answer to your message and the one above it - I agree with you.

[MrSammo1]

37. Speaking logic to the illogical

===============================================================
In Bushworld, jets vaporize or pulverize.
In Bushworld, F-15's don't do their job.
In Bushworld, jet wings fold.
In Bushworld, the laws of physics can change....as needed.
In Bushworld, terrorist hijackers that fly jets into building, can still be alive.
In Bushworld, Osama Bin Laden can change the size of his nose.
In Bushworld, only the FBI can understand what Osama says in videos.
In Bushworld, Osama's relatives don't need to be questioned, and can be allowed to fly out of the US when no one else can.
In Bushworld, steel structure buildings implode demolish style and fall at or faster than free fall speeds.
in Bushworld, steel has the same density as air.
in Bushworld, steel beams don't bend, but break like glass.
In Bushworld, if anyone doesn't buy the lies surrounding 9/11, he isn't a patriot.
===============================================================

[NecessaryOnslaught]

14. How come there is one hypothesis that has been left out..

of every single gubnment report?

[LARED]

15. What hypothesis is that? (n/t)

[vincent_vega_lives]

16. Thought this was worth a post...

check out this bridge.

http://www.ehowa.com/features/alabamatruck.shtml

A fuel tanker crashed and burned at one of Alabama's busiest highway interchanges during morning rush hour today. The fiery wreck partially melted a bridge and could result in months of traffic problems while the overpass is demolished and replaced. The wreck -- which occurred at the intersection of Interstates 20/59 and 65 -- was the second such crash at "malfunction junction" since January 2002. Authorities said a tanker carrying fuel overturned in a curve about 7 a.m., spilling an estimated 9,000 gallons of fuel that erupted into flames and sent a huge column of black smoke skyward.

[LARED]

17. Should be titled

"Truck Driver Suspends Laws of Physics" :)

[RH]

18. Obviously

the bridge was hit by a missile armed with a reto-fitted shaped charge with demolition charges placed in advance!

Is there no end to the mischief?

[AZCat]

20. Interesting. Here's a link to an article about the first crash (1/02)

High Traffic Bridge Rebuilt in Record Time

I see that they've already awarded a contract for the replacement. Wow, that was fast. And they say it should be done by the end of the year.

[DulceDecorum]

29. Concrete, cash and coincidence.

vincent_vega_lives says: check out this bridge.

And so we shall.
The wreck -- which occurred at the intersection of Interstates 20/59 and 65 --
WAS THE SECOND SUCH CRASH at "malfunction junction" since January 2002.
http://www.ehowa.com/features/alabamatruck.shtml

WOT?
Couldn't get it right crispy on the first try eh?

When a crash occurs on any main traveled artery, it could back traffic up for miles-thereby causing a chain reaction affecting every route within that vicinity. When this occurs on an interchange at three major corridors, and a well-traveled bridge becomes damaged beyond use, you have the makings of a major congestion-mitigation emergency. This was the case in Birmingham, Alabama on January 5, 2002. The I-65/20-59 interchange route was engulfed in a confusion of smoke. Local residents as well as traveling motorists didn't know what was causing the skyline to be filled with smoke.
<snip>
When Mr. Miller Gorrie, Chairman/CEO of Brasfield and Gorrie (who had a key role in rebuilding the bridge) walked outside that Saturday morning, he saw smoke rising in the west and wondered what was going on. At first, he thought his church was on fire, it hadn't been that long ago when they had to replace it due to a fire, but then he realized it was on the other side of town. As he drove downtown and got closer he was told that the I-65 Southbound Bridge was closed. Understanding the severity of congestion that this could cause, Mr. Gorrie called his old schoolmate Mr. Walter Morris, President of The Morris Group, Inc (another important key contributor) to tell him about a bridge building opportunity.
<snip>
Because of the accelerated time that the bridge had to be completed, they used concrete girders. They could not afford the time delay that the steel girders would cause. Also, to accommodate future widening of Northbound I-65 to include another lane and wider shoulders, the original 120-feet span length was increased to 140 feet. In addition, 0.6-inch diameter strand was used instead of the normal ½ inch diameter. Quick on the spot decisions had to be made in order to get bids in and a contract awarded.
<snip>
Opening Day, February 27, Governor Siegelman cuts the ribbon officially opening I-65 Southbound lane and I-59 Southbound lane ramp to I-65 Southbound traffic. The evidence of success stood between the once damaged bridge for all to see. ALDOT couldn't have felt more proud of their accomplishment than the State of Alabama as a whole. No one ever thought that this interchange emergency recovery project could have taken off so swiftly and been completed in 37 days and only 53 days after the crash had taken place. With the original projection date being April 20th, you too must see and feel the pride of everyone who had anything to do with this record-breaking project.
http://www.fhwa.dot.gov/resourcecenter/sucess10.htm
http://www.tfhrc.gov/pubrds/02sep/05.htm

Wednesday, May 15, 2002
The replacement for a Birmingham, AL, bridge destroyed in a truck crash will be named in honor of the truck driver who lost his life in an effort to spare others. The new bridge was built in less than 40 days.
The original Interstate 65 south bridge at the junction with I-20/59 was destroyed on Jan. 5 when a tanker truck driven by Tim Dison of Killen, AL, jackknifed into the bridge supports after reportedly swerving to avoid a car that cut in front of him. The crash killed Dison and the resulting heat from the fire caused the steel girders in the overpass to buckle and bend the ramp.
Rep. John Rogers of Birmingham sponsored a resolution in the state legislature naming the structure the Tim Dison Memorial Bridge.
http://www.njmta.org/articles.dws?section=12&id=54

I have told you people before that it is the CONCRETE that is the problem
In the rebuilding of this bridge,
they used high-strength quick-setting concrete.
Just like they did when the rebuilt that wedge of the Pentagon.
And I am telling you all,
here and now, that
the Pentagon is going to go up in flames.
AGAIN.
And it is the concrete that is at fault.

"The choice to use concrete was the primary reason the bridge was finished ahead of schedule," said Duncan Morris of The Morris Group, Inc., who added that the mix design used on the project was reaching the required strength within 40 hours. "This allowed the substructure of the bridge to be finished ahead of schedule."
Sherman Ready Mix, the concrete supplier, committed to 24-hours-a-day, seven-days-a-week support of the project to ensure an early completion and to return the bridge to normal traffic as quickly as possible. The company dispatched more than 400 truckloads of concrete - for a total of about 2,400 yards -- using Mack trucks outfitted with MTM concrete mixers. Some 1,900 yards of this total was a HIGH EARLY STRENGTH MIX that achieved strength in two to three days as opposed to the original estimated 14 days.
<snip>
The new Interstate 65 bridge was reopened to traffic on Feb. 26, just seven weeks after the disaster, an achievement that was celebrated with a quick ribbon cutting by Alabama Governor Don Siegelman. During the ribbon cutting ceremony, Gov. Siegelman thanked commuters for their patience - and also thanked the construction crews for their diligent work which made this replacement project happen in record time.
http://www.alconcrete.org/memberInformation/dixieContractor.cfm

February 26, 2002
Birmingham general contractor Brasfield & Gorrie LLC (http://www.brasfieldgorrie.com) and bridge and foundation contractor The Morris Group Inc. finished the 60-foot span 52 days ahead of their 90-day, $2.1 million contract. They will split a $1.3 million bonus (at $25,000 per day) for finishing ahead of schedule. Had they failed to meet the deadline, they would have lost $25,000 per day in fines.
http://birmingham.bizjournals.com/birmingham/stories/2002/02/25/daily12.html?t=printable

August 28, 2002
The Interstate 65 South bridge built by Birmingham general contractor Brasfield & Gorrie LLC and The Morris Group Inc. to replace an overpass destroyed in the Jan. 5 explosion of an 18-wheel tanker truck has been named one of the state's 10 most outstanding projects over the past 150 years by the Alabama section of the American Society of Civil Engineers.
http://birmingham.bizjournals.com/birmingham/stories/2002/08/26/daily22.html

FAST FORWARD FROM 2002 TO 2004.

Friday, October 22, 2004
A truck carrying 9,000 gallons of fuel crashed at 6:57 a.m. Thursday, exploding on Alabama's busiest interstate interchange, warping and destroying a bridge and possibly forcing detours for up to four months. The driver survived unhurt.
Repair work closed the bridge on Interstate 20/59 North at Interstate 65 while up to $4 million in repairs are made. Initial work to demolish the bridge will keep the other lanes of I-20/59 South beneath the bridge closed through the weekend.
Around-the-clock work began immediately. State Department of Transportation officials said the bridge was being torn down so traffic could resume flowing beneath on I-20/59 South before Monday's rush hour.
The fire's heat, estimated at greater than 1,700 degrees, was so severe the bridge's steel girders twisted and stretched, forcing the concrete to buckle in waves. Some of the spilled fuel ran along the interstate into a ravine, burst into flames and burned nearby brush, trees, a lamp post and the columns supporting the bridge.
It took Birmingham firefighters nearly 30 minutes to put out the blaze, then to clean up the spill and prevent it from flowing into a nearby creek.
"It was a horrendous accident," Gov. Bob Riley said during a news conference with Birmingham Mayor Bernard Kincaid and state Department of Transportation officials. "It was amazing, astonishing."
Thursday's accident was near the scene of a deadly January 2002 tanker explosion beneath the I-20/59 ramp to I-65 South, also at what is called Malfunction Junction. The connector was replaced in 38 days for $3 million, work sped by a promise of incentives from the state.
"IT'S THE SECOND VERSE,SAME SONG," said J.F. Horsley, division engineer for DOT.
The bridge that was destroyed Thursday is longer and could take more time to repair, officials said.
http://www.al.com/news/birminghamnews/index.ssf?/base/news/109843667176530.xml

Saturday, October 23, 2004
Birmingham police have yet to say what caused Bryan Gerald's tanker carrying 9,000 gallons of fuel to flip, slide and explode beneath the bridge. Gerald, 33, walked away from the crash and was at his parents' home in Chelsea recuperating with cuts and bruises.
Gerald's father said Friday his son told him he was making a turn on the I-65 North ramp to 20/59 South and the back of the truck shifted. "He said the way the back of the trailer sat down, he couldn't control it," Flynn Gerald, 65, said. "He almost pulled it back around, but then it got away from him."
Gerald was able to unbuckle his seat belt, get out and run, his father said. As soon as he got away from the truck it was in flames, Flynn Gerald said. "We're thankful to God he was able to get out."
http://www.al.com/news/birminghamnews/index.ssf?/base/news/109852298240270.xml

BEEN THERE, DONE THAT.

POSTED: 7:28 pm CDT October 29, 2004
UPDATED: 7:57 pm CDT October 29, 2004
BIRMINGHAM, Ala. -- The Alabama Department of Transportation announced Friday that a $5,450,000 contract has been awarded to replace the bridge at the Interstate 20/59 and Interstate 65 interchange that was destroyed on Oct. 21 as a result of a tanker truck accident.
Brasfield & Gorrie, LLC, and the White Morris Group of Birmingham were awarded the contract. Completion is scheduled for Dec. 31 at the latest.
Construction will begin immediately and the construction team will work around the clock to replace the bridge. A $50,000-a-day incentive will be paid to the contractor for every day the project is completed early, and a $50,000-a-day penalty will be assessed if the work goes past the deadline
http://www.nbc13.com/news/3875629/detail.html

One is happenstance.
Two is coincidence.
Three is enemy action.
-- Auric Goldfinger

NOW LETS TALK ABOUT CONCRETE.

Good concrete attains high compressive strength and resistance against most natural attacks though not against de-icing saltwater, or CO2 and SO2 in polluted air. However, its tensile strength is low, and the use of concrete alone is therefore limited to structures which are only subject to compressive stresses. But tensile stresses also occur in abutments and piers due to earth pressure, wind, breaking forces and to internal temperature gradients.
To resist these tensile forces, steel bars must be embedded in the concrete, the so-called reinforcing bars, and this has lead to the development of reinforced concrete. The steel bars only really come into play after the concrete cracks under tensile stresses. If the reinforcing bars are correctly designed and placed, then these cracks remain as fine "hair cracks" and are harmless. A second method of resisting tensile forces in concrete structures is by prestressing.
<snip>
Amongst bridge materials steel has the highest and most favourable strength qualities, and it is therefore suitable for the most daring bridges with the longest spans. Normal building steel has compressive and tensile strengths of 370 N/mm2, about ten times the compressive strength of a medium concrete and a hundred times its tensile strength. A special merit of steel is its ductility due to which it deforms considerably before it breaks, because it begins to yield above a certain stress level. This yield strength is used as the first term in standard quality terms.
For bridges high strength steel is often preferred. The higher the strength, the smaller the proportional difference between the yield strength and the tensile strength, and this means that high strength steels are not as ductile as those with normal strength.
http://www.nireland.com/bridgeman/Bridging%20Materials.htm

In other words,
the steel takes over where the concrete fails.
Also,
the steel used in bridge-building
is not stuff that bends easily
for any reason whatsoever.
If you look at the photos,
you will see that the bridge did indeed sag,
but that is primarily the fault of the concrete,
most especially if it was constructed using High Alumina Cement.

HAC differs from Portland cement, being composed of calcium aluminates rather than calcium silicates. Its rapid strength development made HAC popular for precast concrete in the UK during the 1960s. Mineralogical ‘conversion' however, sometimes caused catastrophic reductions in concrete strength and increased vulnerability to chemical degradation.
http://www.sandberg.co.uk/labs/f020r05.htm

In other words,
acid rain rots the concrete.
Healthy HAC also fails dramatically when exposed to high temps.
As it loses the moisture that is holding it together,
it explodes or peels off in layers.
This is called spalling.

The NIST Building and Fire Research Laboratory (BFRL) has undertaken a project concerning the effect of fire on high strength concrete. Heating concrete to sufficiently high temperatures results in water of hydration being driven off, with a resultant irreversible loss of concrete strength. In addition, it has been observed that rapid heating of high strength concrete can result in spalling of the concrete.
http://fire.nist.gov/bfrlpubs/fire99/art010.html

Thus, in light of the results of recent studies which have shown that HSC behavior at elevated temperature may be significantly different from that of NSC , question may be raised as to whether existing design rules and recommendations are applicable to HSC.
http://fire.nist.gov/bfrlpubs/build03/art020.html

The steel reinforcement inside concrete is prone to rust.
This reaction is caused by acid rain and ordinary rain
seeping inward via cracks in the outer concrete.
The alumina (or magnesia) in HAC has been known to react with this rust
to cause a thermite reaction.

Another great example of a thermodynamically spontaneous reaction is the thermite reaction. Here, iron oxide (Fe2O3 = rust) and aluminum metal powder undergo a redox (reduction-oxidation) reaction to form iron metal and aluminum oxide (Al2O3 = alumina):
Fe2O3(s) + 2 Al(s) Al2O3(s) + 2 Fe(l)
This reaction is so exothermic that the iron is actually molten! In fact, thermite has been used for underwater welding.
http://www.ilpi.com/genchem/demo/thermite/

Fat lot of good those fire hoses are going to do.
Oh sorry, I forgot.
Only Penta-firemen from Fort Myer use water on fossil-fuel fires.
Anyway,
once that gasoline gets the reaction good and started,
that thermite reaction takes on a life of its own.
It does not need additional oxygen,
so that suppressant foam is virtually useless.

Now, the Twin Towers were made of this High-strength Concrete
and that is why they burned like cigarettes.
The steel was blamed,
but it was really the fault of the damn concrete.

December 1998
Past experiments have shown that HIGH TEMPERATURES SIGNIFICANTLY WEAKEN HSC (High Strength Concrete). IT HAS HIGHER POTENTIAL FOR SUDDEN FAILURE than normal strength concrete WHEN EXPOSED TO TEMPERATURES OF 350 DEGREES CELSIUS OR HIGHER.
THESE TEMPERATURES ARE WELL BELOW THE RANGE OF A TYPICAL BUILDING FIRE, AND RESEARCHERS BELIEVE THE SUDDEN FAILURE OF HSC IN FIRES POTENTIALLY COULD TRIGGER CATASTROPHIC BUILDING COLLAPSES. HSC has been gaining in use in recent decades in buildings ranging from the TRUMP TOWER New York to the CHICAGO MERCANTILE EXCHANGE. Designers and building owners favor HSC because it allows the use of smaller beams and columns, resulting in more usable space, lighter structures and lower foundation costs. The results of the NIST study may be incorporated into future building codes to guide designers in the safe use of HSC.
http://www.nist.gov/public_affairs/techbeat/tb9812.htm

And while we are on the subject,
EVERY SINGLE BIT OF CONCRETE IN THE US IS FAILING.
Those skyscrapers are on their way down.
Just wait and see.

The corrosion problem of steel rebar is the greatest factor in limiting the life expectancy of reinforced concrete structures. In some cases the repair costs can be twice as high as the original ones. In North America, this phenomenon has been exacerbated in parking garages and bridge decks by the use of de-icing salts and significant fluctuations of temperature. In Canada, it is estimated that the cost of repair of parking garages is in the range of six billion dollars, and over 74 billion dollars for all concrete structures. The estimated repair cost for existing highway bridges in the U.S. is over 50 billion dollars, and one to three trillion dollars for all concrete structures. In Europe, steel corrosion has been estimated to cost about 3 billion dollars per year. Excessive corrosion problems also exist in Arabian Gulf countries. Deterioration in all types of reinforced structures is aggravated by excessive concentration of chlorides in construction materials, high humidity, temperatures, and marine exposure.
http://www.civil.usherbrooke.ca/chaire/alternative.htm

And please,
don't blame the Muslims.
It is the CHRISTIANS
who decided to use
pulverized bisqued clay, and iron
as construction materials.

[AZCat]

30. I seem to be missing something here...

In your post, you state that:
<quote>
The steel reinforcement inside concrete is prone to rust.
This reaction is caused by acid rain and ordinary rain
seeping inward via cracks in the outer concrete.
The alumina (or magnesia) in HAC has been known to react with this rust
to cause a thermite reaction.
</quote>
I looked for information about a reaction between alumina and rust, but all I could find was a previous DU thread that had a similar discussion. Everything I found about the thermite reaction has alumina as a product, not a reactant. Where can I find information either on the reaction in question (rust + alumina) or studies about this phenomenon?

[vincent_vega_lives]

31. WOW

You never fail to disappoint when one of your pet notions are threatened.

you will see that the bridge did indeed sag,
but that is primarily the fault of the concrete,

Joking right? The I-beam bending had nothing to do with weakening due to the fire? The concrete road bed is not load bearing.

[demodewd]

19. poor

Let's hope the NIST report goes into a much more lengthly and detailed SCIENTIFIC analysis of the collapses. What you present here is a skeletal analysis that could have been drawn up by most any untrained person including you or me. Is this the NIST synopsis? Poor. I could do better in my sleep.

[Bill66]

22. Try here

http://www.icivilengineer.com/News/WTC/structure.php

or

http://www.fema.gov/library/wtcstudy.shtm

[LARED]

23. You should check this link often

http://wtc.nist.gov/

[drunkdriver-in-chief]

24. Hey dood - What about WTC -7?

Nothing hit it but it also collapsed str8 down into its own foundation!!!

[vincent_vega_lives]

27. FIRE

Unfought, allowed to burn, fuel, unique structure that contributed to collapse.

[MercutioATC]

28. Just give me one scientific reason that you think this is suspicious.

The computer modeling of the collapse explained things. You disagree with the conclusions. Show me a scientific reason the models are wrong (something concrete, not just "I don't believe anything the government says").

[hangloose]

34. Video's of the collapse of WTC # 7 show demolition charges

going off prior to and during the event. It's without question the WCT was pulled, the building owner made this statement in an interview with the media on September 11th. This brings up a big question, doesn't it?

[LARED]

35. The big question is

why anyone with more than a few functioning brain cells believe the video shows demolition charges going off or why they think the building owner stating it was pulled, means it was demolished?

For those than do not know, pulled means to pull the firefighters out of the building, not pull the building down.

[hangloose]

38. I respectfully disagree on both comments

"Pulled" is a term used by professional demolition companies to refer to the controlled demolition of buildings. There are only three instances of complete structural failure associated with fire in steel reinforced high-rises, ever. Those are WTC 1, WTC 2, and WTC 7.

Two professional demolition companies (experienced in high-rise controlled demolition) were shown videos of the collapse of WTC 7 and both stated that the near vertical collapse of the entire structure(simultaneously) was consistent with controlled demolition.

There are videos available that show suspicious explosions occurring on several floors as the building drops.

[RH]

39. The context of the "pull",

if you actually bother to look at it, was of firefighting, not one of demolition.

[hangloose]

40. I did bother which is why said what I said. So were not talking

past one another what reference are you referring to? My comment referenced a interview taped with the building owner. I don't have the transcript in front of me but (paraphase) he said (because of the fire, well, we decided to pull it. He didn't say we decided to pull the firemen out from the building. And in that context, he meant bring the building down.

[m000]

41. Why wouldn't they?

Think about it. If one of the towers "fell over" a large part of downtown New York would be crushed. Maybe engineering experts were afraid of the towers falling over and blew it up themselves so it would collapse on its own footprint. Or maybe the fire-control engineers decided the risk of having the fire spread was too great.

Now while this may have been the logical and rational thing to do, I think you can understand the political motive for keeping it hush-hush.

I had considered this, because I recall that tape too -- some official admitted to pulling the tower. I merely assumed I misunderstood.

I figured if it did happen, it wouldn't be kept a secret for long. Considering the number of people involved (bystanders, construction workers, demolition team, etc, etc) something like that would get out sooner or later.

So I suspect that actually jet fuel burned in such a way not yet seen before (the flight had just taken off, and was fully fueled) which melted the structure.

[hangloose]

44. The only problem with that scenario is the building was demolished

within 12 hours of the first plane hitting WTC-1. Now are you telling me that once a decision was made to pull WTC-7 a group of trained demolition experts were called and within a few hours rigged the building with explosives (keep in mind the building was on fire!) then brought the building down all before dusk that same day. Highly unlikely. In fact a million to one. This was all planned in advance.

The CIA directorate was in the basement.

The fire department didn't even attempt to put out the fire.

It's all a whitewash, and I agree obvious. But hide in plane sight.

[RH]

42. "we"

did not refer to any discussion with a demolition contractor.

He was talking about a telephone discussion with the fire department commander.

So instead of presuming to tell us what Silverstein meant do you think it may be a better idea at least to ask him what he meant?

[hangloose]

45. Brother your tough.

I didn't write Silverstein has any discussion with demolition contractors (experts in their field) that tid bit of information was an aside, another conversation between other people and had nothing to do with Silverstein.

The comment concerning the demolition contractors was added to highlight the convenient vertical collapse of this particular building on it footprint. Caused by what? A symmetrical fire that happened to weaken all the main support columns of the building causing a catastrophic but convenient drop of the entire structure with no loss of life or damage to surrounding buildings.

By the way Silverstein made a Hugh amount of money from the destruction of the WTC, Hugh.

[vincent_vega_lives]

47. Hardly "symmetrical" or "covenient"

The building could never have collapsed in anything else but in the vertical.

[vincent_vega_lives]

48. So then

There would have been det cord, wiring, and explosive residue on the site right?

[hangloose]

33. If your Hypothese is correct then I would expect that

the lower floors (below the impact) for the greater part were completely unaffected by the impact of the plane and the ensuing fire. If that is a reasonable assumption one would have to conclude that the systematic collapse of the upper floors onto the lower floors would be meet "initially" at each successive level with resistant, slowing the collapse of the structure. If one watches the collapse of the structures you will see that they fall at a rate of speed that equal free fall of an object with no resistance. Compare the structure speed of collapse with the discharged building debris which is free falling adjacent to the structure. The free falling debris never gets ahead of the collapsing building. Your explaination doesn't address this curious situation.

[vincent_vega_lives]

46. Wrong

"rate of speed that equal free fall of an object with no resistance"

Just plain wrong.

[LARED]

49. If one watches the collapse

of the structures you will see that they fall at a rate of speed that equal free fall of an object with no resistance

Not even close to accurate. The WTC 1 & 2 buildings all fell less than free fall speeds by a few seconds.

[Dancing_Dave]

50. What total BS!

This does not provide any explanation whatsoever of what blew the structure to smithereens, demolishing it to a fine powder which poisoned the City of New York--oh yeah, the sold out Government "experts" tried to deny that fact to. Another killing deception.

The NIST doesn't get anywhere near touching on WHAT REALLY HAPPENED TO THAT STRUCTURE. There's plenty of photographic, video and eyewitness accounts of the explosive disintigration. Nothing in the NIST report provides anywhere near enough energy to blow all this matter to such a fine powder.

These three documents should suffice to explain the REAL issues to anyone who is concerned with Truth and Justice for what happened on 9/11/2001:

http://www.nyenvirolaw.org/wtc-index.htm
http://serendipity.ptpi.net/wtc.htm
http://plaguepuppy.net/public_html/collapse%20update/


http://www.physics911.org/ recently had it's open source site hacked down, well the election was hacked with permanent results but I'm hoping the highly informative physics911.org site will recover from the corruption and be available to the public again soon.

[Aries]

51. UL Expert: WTC Steel "should have easily withstood the thermal stress "

Dear 9/11 Trutch activists and concerned citizens,

With permission, we are forwarding you the following letter sent today by Kevin Ryan of Underwriters Laboratories to Frank Gayle of the National Institute of Standards and Technology (NIST). Underwriters Laboratories is the company that certified the steel componets used in the constuction of the World Trade Center towers. The information in this letter is of great importance.

Towards peace and truth,
Emanuel Sferios
Webmaster, www.SeptemberEleventh.org


This letter is also on the web:
http://www.septembereleventh.org/newsarchive/2004-11-11-ryan.php

From: Kevin R Ryan/SBN/ULI
To: [e-mail]
Date: 11/11/2004


Dr. Gayle,

Having recently reviewed your team's report of 10/19/04, I felt the need to contact you directly.

As I'm sure you know, the company I work for certified the steel
components used in the construction of the WTC buildings. In requesting information from both our CEO and Fire Protection business manager last year, I learned that they did not agree on the essential aspects of the story, except for one thing - that the samples we certified met all requirements. They suggested we all be patient and understand that UL was working with your team, and that tests would continue through this year. I'm aware of UL's attempts to help, including performing tests on models of the floor assemblies. But the results of these tests appear to indicate that the buildings should have easily withstood the thermal stress caused by pools of burning jet fuel.

There continues to be a number of "experts" making public claims about how the WTC buildings fell. One such person, Dr. Hyman Brown from the WTC construction crew, claims that the buildings collapsed due to fires at 2000F melting the steel (1). He states "What caused the building to collapse is the airplane fuel…burning at 2,000 degrees Fahrenheit. The steel in that five-floor area melts." Additionally, the newspaper that quotes him says "Just-released preliminary findings from a National Institute of Standards and Technology study of the World Trade Center collapse support Brown’s theory."

We know that the steel components were certified to ASTM E119. The time temperature curves for this standard require the samples to be exposed to temperatures around 2000F for several hours. And as we all agree, the steel applied met those specifications. Additionally, I think we can all agree that even un-fireproofed steel will not melt until reaching red-hot temperatures of nearly 3000F (2). Why Dr. Brown would imply that 2000F would melt the high-grade steel used in those buildings makes no sense at all.

The results of your recently published metallurgical tests seem to clear things up (3), and support your team's August 2003 update as detailed by the Associated Press (4), in which you were ready to "rule out weak steel as a contributing factor in the collapse". The evaluation of paint deformation and spheroidization seem very straightforward, and you noted that the samples available were adequate for the investigation. Your comments suggest that the steel was probably exposed to temperatures of only about 500F (250C), which is what one might expect from a thermodynamic analysis of the situation.

However the summary of the new NIST report seems to ignore your findings, as it suggests that these low temperatures caused exposed bits of the building’s steel core to "soften and buckle"(5). Additionally this summary states that the perimeter columns softened, yet your findings make clear that "most perimeter panels (157 of 160) saw no temperature above 250C". To soften steel for the purposes of forging, normally temperatures need to be above1100C (6). However, this new summary report suggests that much lower temperatures were be able to not only soften the steel in a matter of minutes, but lead to rapid structural collapse.

This story just does not add up. If steel from those buildings did soften or melt, I’m sure we can all agree that this was certainly not due to jet fuel fires of any kind, let alone the briefly burning fires in those towers. That fact should be of great concern to all Americans. Alternatively, the contention that this steel did fail at temperatures around 250C suggests that the majority of deaths on 9/11 were due to a safety-related failure. That suggestion should be of great concern to my company.

There is no question that the events of 9/11 are the emotional driving
force behind the War on Terror. And the issue of the WTC collapse is at the crux of the story of 9/11. My feeling is that your metallurgical tests are at the crux of the crux of the crux. Either you can make sense of what really happened to those buildings, and communicate this quickly, or we all face the same destruction and despair that come from global decisions based on disinformation and “chatter”.

Thanks for your efforts to determine what happened on that day. You may know that there are a number of other current and former government employees that have risked a great deal to help us to know the truth. I've copied one of these people on this message as a sign of respect and support. I believe your work could also be a nucleus of fact around which the truth, and thereby global peace and justice, can grow again. Please do what you can to quickly eliminate the confusion regarding the ability of jet fuel fires to soften or melt structural steel.

1. http://www.boulderweekly.com/archive/102104/coverstory.html
2. CRC Handbook of Chemistry and Physics, 61st edition, pg D-187
3. http://wtc.nist.gov/media/P3MechanicalandMetAnalysisofSteel.pdf
4. http://www.voicesofsept11.org/archive/911ic/082703.php
5. http://wtc.nist.gov/media/NCSTACWTCStatusFINAL101904WEB2.pdf (pg 11)
6. http://www.forging.org/FIERF/pdf/ffaaMacSleyne.pdf

Kevin Ryan

Site Manager
Environmental Health Laboratories
A Division of Underwriters Laboratories

-- For more information about UL, its Marks, and its services for EMC,
quality registrations and product certifications for global markets,
please access our web sites at http://www.ul.com and http://www.ulc.ca, or contact your local sales representative.

[LARED]

52. Good Lord

There's so much BS it hard to figure out where to start.

How about the first sentence

Kevin Ryan of Underwriters Laboratories

Absolute BS. if this guy is actually real he works for Environmental Health Laboratories, a 10 year old water testing company.

[Aries]

53. Fire Tests of Building Construction and Materials

http://ulstandardsinfonet.ul.com/scopes/0263.html

Fire Tests of Building Construction and Materials
UL 263

1 Scope
1.1 These fire tests are applicable to assemblies of masonry units and to composite assemblies of structural materials for buildings, including bearing and other walls and partitions, columns, girders, beams, slabs, and composite slab and beam assemblies for floors and roofs. They are also applicable to other assemblies and structural units that constitute permanent integral parts of a finished building.

1.2 The classifications for building construction and materials are intended to register performance during the period of fire exposure and are not intended to be interpreted as having determined their acceptability for use after fire exposure.

1.3 These requirements are intended to evaluate the length of time that the types of assemblies specified in 1.1 will contain a fire or retain their structural integrity, or both, dependent upon the type of assembly involved, during a predetermined test exposure. The test evaluates the assembly's resistance to heat, and in some instances to a hose stream, while carrying an applied load, if the assembly is load bearing.

1.4 Under these requirements a specimen is subjected to a standard fire exposure controlled to achieve specified temperatures throughout a specified time period. In some instances, the fire exposure may be followed by the application of a specified standard fire hose stream. This exposure by itself may not be representative of all fire conditions; conditions may vary with changes in the amount, nature, and distribution of fire loading, ventilation, compartment size and configuration, and heat sink characteristics of the compartment. These requirements provide a relative measure of fire performance of comparable assemblies under these specified fire exposure conditions. Any variation from the construction or conditions that are tested such as size, method of assembly, and materials, may substantially change the performance characteristics of the assembly.

1.5 These requirements cover the following measurements and determinations during the test exposure:

Measurement of the transmission through the assembly of heat, and of gases sufficiently hot to ignite cotton waste in walls, partitions, floors, and roofs.
Measurement of the load carrying ability of load bearing elements in wall, partition, floor, and roof assemblies.
Measurement of the load carrying ability of individual load bearing assemblies, such as beams and columns, with consideration for the end support conditions, either restrained or not restrained.
1.6 These requirements do not cover:

Accumulation of data as to performance of assemblies constructed with components or lengths other than those tested.
Evaluation of the contribution of the assembly to generation of smoke, toxic gases, or other products of combustion.
Measurement of the degree of control or limitation of the passage of smoke or products of combustion through the assembly.
Simulation of the fire behavior of joints between building elements, such as floor-wall or wall-wall, and like connections.
Measurement of flame spread over the surface of the tested element.
The effect on fire endurance of conventional openings in the assembly, such as openings for electrical receptacle outlets, plumbing pipe, or the like, unless specifically provided for in the construction tested.

1.7 Tests for burning characteristics of building materials, based on the rate of flame spread, can be found in the Standard for Test for Surface Burning Characteristics of Building Materials, UL 723.

1.8 The tests described herein may be cited as the "Standard Fire Tests," and the performance of exposure expressed as "2-hour," "6-hour," "1/2-hour," or the like.

1.9 The results of these tests represent one factor in assessing fire performance of building construction and assemblies. These requirements prescribe a standard fire exposure for comparing the performance of building construction assemblies. Application of these test results to predict the performance of actual building construction requires careful evaluation of test conditions.

1.10 If a factor of safety exceeding that inherent in the test conditions is desired, a proportional increase should be made in the specified time classification period.

[LARED]

54. Very nice link

Is there a point you are trying to make?

[Aries]

55. Just that it's not a "water testing company"

and it has expertise in the relevant area.

Do you have a specific technical objection to anything in the letter, other than your ad hominems?

[WoodrowFan]

56. Did you see the NOVA about the Swiss Air crash a few years ago.

They figured out that it crashed due to a fire (which they knew about) because of an arc in wires in the insulation. The insulation had originally passed the fire tests back in the 70s. When they retested it after the crash using newer methods, the insulation failed the test. As a result it's being replaced in newer planes. (but a lot of old planes still have it!, thanks FAA!)

http://www.pbs.org/wgbh/nova/aircrash/


The point is, the tests on the steel were done 30 years ago (roughly). Are the results still valid??? Or would newer methdology reveal a previously unknown flaw??