Wtc 7 And Sandero, NIST v speculation Options

[elreb]

The fire on floor 12 was first recorded at about 2:08, along the southeast face. The photos continued until about 2:28.

There were no generators, day tanks or transformers on the 12th floor.

This was the heart of the “Securities and Exchange Commission”.

Fire Sprinkler Systems do not require electricity to operate. “Head” temperature range from 135 to 286 degree F and have a line pressure around 175 psi.

Paper self-ignites at 461 degree F.

Water would have to be over 1832 degree F to become combustible.

[SanderO]

Sprinkler that are gravity fed don't but they do require pumps to lift the water to tanks. How do you get water up to such heights without lift pumps?

[elreb]

Sprinkler that are gravity fed don't but they do require pumps to lift the water to tanks. How do you get water up to such heights without lift pumps?

Each system is different

You will lose .434 PSI per foot of rise therefore if the 12th floor were 120 feet up, you would lose 52.08 PSI

Most high rise buildings would have fire pumps and a remote Siamese connections on the exterior.

Fire engines can connect to these exterior fittings and use their pumps to drive the pressure back up.

Standard New York water pressure is around 80 PSI at a fire hydrant.

As a note: Water towers work in the reverse and gain .434 PSI per foot

So was the power on or was it off? You can’t have it both ways.

[kawika]

Each system is different

You will lose .434 PSI per foot of rise therefore if the 12th floor were 120 feet up, you would lose 52.08 PSI

Most high rise buildings would have fire pumps and a remote Siamese connections on the exterior.

Fire engines can connect to these exterior fittings and use their pumps to drive the pressure back up.

Standard New York water pressure is around 80 PSI at a fire hydrant.

As a note: Water towers work in the reverse and gain .434 PSI per foot

So was the power on or was it off? You can't have it both ways.

There are photos of engines hooked up to standpipes next to WTC7. There are reports of them taking hoses into stairwells early on before there were any fires.

The official story was a main got broken after WTC2 fell rendering the rest of Manhattan hydrant challenged. Yet we see people washing at hydrants, water being poured on WTC5 and 6, other buildings on Liberty Street, fire boats tied up at the dock two blocks away pumping 60K gallons per minute, reports of car fires being put out north of WTC7 on W. Broadway right down to Barclay. But no water for fighting fires inside.

After the collapse they were dumping water on the pile from the Verizon bldg. and ladder trucks.

What gives?

[SanderO]

I think the power was lost coming from the B7 sub station. Con Ed can maintain the grid with a few offline sub stations and I suppose they were switching things around a bit that day.

Water mains are of varying size like any distribution system... depends on how far up the line the break was. Since the mains are coming from north... downtown has relatively smaller branches. Obviously SOME mains ruptured and others didn't.

[kawika]

I think the power was lost coming from the B7 sub station. Con Ed can maintain the grid with a few offline sub stations and I suppose they were switching things around a bit that day.

Water mains are of varying size like any distribution system... depends on how far up the line the break was. Since the mains are coming from north... downtown has relatively smaller branches. Obviously SOME mains ruptured and others didn't.

The water system failure makes no sense to me. They would simply isolate the break and the rest would be charged again. I have requested records about this, but they claimed there were no repair reports to share. The water distribution system also falls under the "critical infrastructure" exemption.

If you are in NYC, please go and talk to the water department to find out exactly what was up and running and what wasn't. Somewhere after 9/11 they repaired the lines. There have to be records.

[elreb]

What gives?

I’m surprised that Stephen Spielberg hasn’t picked up on this and made a move called “The day nothing worked right”.

"Toast will always land butter side down" on 911

Due to the possibility of hostile cows, the toast was buried in a secret location.

As a note:

95% of NYC water is gravity feed and is on a looped system

(IMG:http://ars.sciencedirect.com/content/image/1-s2.0-S0895717708001131-gr4.jpg)

[onesliceshort]

reports of car fires being put out north of WTC7 on W. Broadway right down to Barclay. But no water for fighting fires inside.

Don't know if you're aware of this video Kawika

http://www.youtube.com/watch?v=JmVRWNNRkP8

extended raw footage from two cameras (cut at 22:18) from about 11:20 am to afternoon sometime.. 911datasets.org release 25, 42A0113 - G25D23
some available in release 14, WNBC Dub3
Lenny Mulhern

WTC7 shots:

20:30, 33:25 - 33:55, 34:35 -  (falling window - timeframe purposes) - 35:35 (grey white smoke - "hole in the building" - other buildings gushing smoke)

And yes, there are shots of water being pumped to put out a car fire across from WTC7 from 20:30 onwards sometime (sorta lost track watching the poor bastards (firefighters) in the middle of that hell - and wondering how many are now ill)

Hope it helps

[kawika]

I am familiar with this series. These were FDNY cameramen who had access to the front lines. They compiled them into a for-sale documentary called FIRELINE. The producer would not tell me details about the raw video. It appears that a sound track was overlaid onto this video. Sound and picture often do not synch.

[elreb]

The good news is that the new WTC7 is the safest skyscraper in the US.

[SanderO]

Some fire trucks contain thousands of gallons of water... and are replenished from hydrants and stand pipes. The high pressure streams of water appear to be from fire apparatus.

This post has been edited by SanderO: May 2 2012, 07:59 AM

[9/11 Justice Now]

Some fire trucks contain thousands of gallons of water... and are replenished from hydrants and stand pipes. The high pressure streams of water appear to be from fire apparatus.

Watch the video here from 3:45 SanderO

WTC7 on 9/11 - Strange Occurrence Within the Last 20 Minutes

http://www.youtube.com/watch?v=biIIqKybSZE

It kind of looks like a plume of smoke from demolition charge going off, what do you think?

Looks like they are cutting a column maybe so they can re distibrute the load and cause the centre columns too fall inwards

[elreb]

Sounds good

[SanderO]

You don't have to melt steel to weaken it.

Steel's yield strength drops as it is heated:

"3 – Steel

The yield strength of steel is reduced to about half at 550 ºC. At 1000 ºC, the yield strength is 10 percent or less. Because of its high thermal conductivity, the temperature of unprotected internal steelwork normally will vary little from that of the fire. Structural steelwork is, therefore, usually insulated.

Apart from losing practically all of its load-bearing capacity, unprotected steelwork can undergo considerable expansion when sufficiently heated. The coefficient of expansion is 10-5 per degree Celsius. Young’s modulus does not decrease with temperature as rapidly as does yield strength.

Cold-worked reinforced bars, when heated, lose their strength more rapidly than do hot-rolled high-yield bars and mild-steel bars. The differences in properties are even more important after heating. The original yield stress is almost completely recovered on cooling from a temperature of 500 to 600 ºC for all bars but on cooling from 800 ºC, it is reduced by 30 percent for cold-worked bars and by 5 percent for hot-rolled bars.

The loss of strength for prestressing steels occurs at lower stressing temperatures than that for reinforcing bars. Cold-drawn and heat-treated steels lose a part of their strength permanently when heated to temperatures in excess of about 300 ºC and 400 ºC, respectively.

The creep rate of steel is sensitive to higher temperatures and becomes significant for mild steel above 450 ºC and for prestressing steel above 300 ºC. In fire resistance tests, the rate of temperature rise when the steel is reaching its critical temperature is fast enough to mask any effects of creep. When there is a long cooling period, however, as in prestressed concrete, subsequent creep may have some effect in an element that has not reached the critical condition."

If the FOS of a steel member was less than 2 heating it to 550°C would see it lose half its strength.. the FOS would be 1 and literally at the edge of failure.

The average FOS for steel high rise structures is 1.42. My calcs for the twin towers' core steel is that it was as low as 1.65 and perhaps 1.85 and not higher than 2.0. Note that not every piece of steel in a structure will have the same FOS. If this is the case... then heating the steel to 600° C would fail the members with FOS of less than 2 and that is possible scenario.

With respect to the twins the FOS was reduced when some of the columns were destroyed by the plane impacts... few columns then supported the same load... FOS drops in the remaining columns. If FOS was 1.85 for starters, with destroyed columns it could be say... 1.33 and you can see how heat could bring the FOS below 1 and cause buckling...

You absolutely do not have to melt the steel to fail the structure from heat.

This post has been edited by SanderO: May 2 2012, 05:48 PM

[elreb]

What ever you say

[elreb]

Where is OSS?

[SanderO]

Elreb,

Did you read the figures quoted for loss of yield strength for steel? You don't believe it?

"The yield strength of steel is reduced to about half at 550 ºC"

If this is true... you don't have to melt steel to buckle it and cause a collapse.

A truss panel/chord is not an axial member (column) and can be either in tension or compression.

It's also true if bracing fails the unbraced length of the column it braces increases and its yield strength decreases.

"For the record: Only a vertical column inherits the weight of the floor above it."

This is not entirely accurate of clear. Columns in multistory structures support the loads on top (axially) and those applied/connected to the web and or flanges. All the floor loads were attached to the sides of columns with beam seats or beam stubs. The loads above were bearing down on the top end of the column (obviously).

This post has been edited by SanderO: May 2 2012, 09:48 PM

[elreb]

What happen to OSS?

[SanderO]

OSS is a typo..should be OOS - open office space means column free long span office floor design...All three towers that fell had them.

When someone cites settle science and engineering the response is not... WHATEVER dismissively.

If this is a fact coupled with typical factor of safeties in steel high rises explains that the steel does NOT have to be melted, but heated to initiate buckling and column failure... leading to a progressive global collapse as failure propagates from one column to the next.

Whatever....

[onesliceshort]

OSS is a typo..should be OOS - open office space means column free long span office floor design...All three towers that fell had them.

When someone cites settle science and engineering the response is not... WHATEVER dismissively.

If this is a fact coupled with typical factor of safeties in steel high rises explains that the steel does NOT have to be melted, but heated to initiate buckling and column failure... leading to a progressive global collapse as failure propagates from one column to the next.

Whatever....

I don't think that the earlier statement "I haven't time to look for evidence" (to support your own claims!) is very "scientific".

I'd just like to point out your contradictory claims on how difficult it would be to bring down WTC7 intentionally compared to your claims on heat being the deciding factor.

Example:

On CD..

AE911T asserts that all 81 columns had to be destroyed over 8 floors instantaneously to account for the observation of the 2.25 second 100 feet free descent of the building seen on the videos. While this could cause a similar observable... it hardly makes sense. Such demolition would be so loud... 81 columns x 4 (the columns were 2 stories each = 324 explosions all at once. Be real... this was not observed. 324 silent cutter charges all completing their cuts at precisely the same instant without any movement as they sut the cross sections of the columns smaller and smaller.... weakening them? I don't think so

Also on CD..(from separate posts)

If there was a CD it was likely on floors 6 and 7.

The explosions could also be from placed charges.

Now this doesn't matter if it was a few bombs (I think it wouldn't take many)

On fires bringing WTC7 down (again separate posts)

I don't think all 81 columns were destroyed at once over 8 floors at the base of the tower as AE911T seems to claim must have happened. I do think the 6th and 7th floor *failed* and the core above it came down.


If one truss *panel* fails... for whatever reason... the entire truss will fail very rapidly as loads are redistributed to remaining truss panels which are overwhelmed. If the 3 trusses let go, a very rapid progression of failures will occur and the core above will have no axial support.

And the fires were precisely in the vulnerable region. A walked off beam would not collapse the entire tower, but a failed transfer truss would.

With B7 my theory is the failure of a truss panel or chord. If you fail one of them the whole truss is a goner. And the T trusses supported the core. And the 2 story T trusses were effectively a bridge over the 6 floors of the Con Ed substation.. up to floor 8. There was only the T trusses between the bottom of the core.. and the ground.. so if the T trusses went the core could drop 8 floors... 100' the same 100 feet of the free fall collapse. Coincidence? I'd say it's a damn good place to look for the "no resistance for 8 floors or 100 feet".

If the building was so vulnerable to heat induced collapse in certain areas, how is CD, concentrating on those same areas so difficult?

Please remember that not only C4 is the only possible explosive on the table (as NIST dishonestly hypothesized).