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In 1999, the tenant of the 81st floor of WTC2, Fuji Bank Limited, carried out further reinforcement work on the "two-way" area with the following reason:
"Documents reference adding reinforcement to existing two-way floor trusses to accommodate new UPS workspace. Documents do not specify the required amount of reinforcement due to the new superimposed loads"
This work was done by the LERA engineering firm, which had been responsible for the structural calculations for the construction of the Twin Towers.
Table 13.2 on page 111 of the NCSTAR 1-1H report again summarizes the reinforcement work performed in several stages by Fuji Bank on multiple floors of WTC2, including the 81st floor and extending also to the 80th and 82nd floors.
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UPS vs UPS
Interestingly, in my opinion there is still an element of doubt, since this table, too, shows that the tenant was Fuji Bank: nothing to do with United Parcel Service.
In the banking and IT sectors, "UPS" has a very specific meaning: Uninterruptible Power Supply. This is the name given to battery-based systems which must ensure the continuous supply of electric power for computer rooms and electrical medical devices which cannot tolerate the slightest power outage.
Isn't it remarkable that the same floor, in the same "two-way" part of the South Tower, exactly where the mysterious flow occurred, was occupied by "UPS United Parcel Service" in 1991 (according to NIST) and by Fuji Bank Limited in 1999 (again according to NIST), and that Fuji Bank carried out reinforcement work "to accommodate new UPS workspace"?
It may well be so, but my personal suspicion is that the acronym "UPS" was misinterpreted as referencing the international courier company but actually referred to one of Fuji's IT resources.
Several sources confirm that data processing equipment related to the computer center was located on that floor: survivors have testified to this, and even pro-conspiracy sources (Christopher Bollyn, some months later) mention an unnamed "deep throat" who claims to have worked in this very facility.
I'd like to point out that the Italian TV program was broadcast several months before these pro-conspiracy rumors circulated. For me, these rumors merely confirmed my initial conjecture, which was based on an analysis of official technical sources.
So the 81st floor of the South Tower apparently had a large portion of its area occupied by the batteries of a UPS which belonged to Fuji Bank. However, this may seem irrelevant to many readers who are not familiar with UPS systems of medium-sized mainframe computers or data centers.
A visit to a UPS facility
In the 1990s I was involved professionally in this field, specifically in robotizing the management of electronic file tapes and in managing the UPS systems of a leading Italian banking group, so I am well acquainted with the safety problems and the physical and chemical characteristics of these batteries.
To explain what a large UPS system looks like to those who are unfamiliar with these devices, I asked a banking service company for permission to take photographs of one of their battery rooms, which resembled the kind that might have been installed on the 81st floor of WTC2. It goes without saying that this is a particularly sensitive and delicate area of a service company, so I will comply with the company's request for anonymity.
Access to this area is adequately protected by doors controlled by badge readers and both technological and security surveillance systems and by armed guards. Only maintenance personnel is normally allowed to enter.
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The following photographs do NOT show WTC2.
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They merely illustrate an example of the possible content of the floor in dispute and suggest a reason why two successive stages of floor truss reinforcement work were necessary in 1991 and 1999.
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(The sign in Italian says "Battery Room - no smoking, no unauthorized access".)
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The photographs clearly show that this kind of UPS consists of a huge number of lead batteries, each capable of supplying a nominal voltage of 2 V. The batteries are connected in series so as to provide a total of 440-480 V, as shown by the measurement instruments (shown below) located outside the battery room.
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Providing 480 V with 2-V batteries requires 240 batteries connected in series to ensure that the electronic systems protected by the UPS are powered long enough to allow mains power to return or to start the Diesel generators.
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The ventilation system requires particular care, since it must allow vigorous air changing: the batteries are composed of two electrodes formed by alternating plates of lead and lead dioxide immersed in an electrolyte (a sulfuric acid solution). They release toxic gases, and especially during quick charging and discharging processes, caused mostly by malfunctions, can release large amounts of hydrogen. This is a highly flammable gas which, combined with oxygen, could trigger violent explosive reactions, as some readers may recall from their college chemistry days.
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For the same reason of possible presence of highly flammable gases, the electrical ventilation and lighting systems must be non-sparking, with cables and lamps which are isolated and sealed hermetically with respect to the battery room environment.
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It goes almost without saying that the fire control system cannot use liquids. Halon systems are used instead, and this accordingly entails considerable safety problems for personnel who might be working inside the battery rooms when an emergency occurs.
Large systems provide breathing bottles for personnel, providing enough air to reach escape routes. This is another reason why access to these areas is so restricted. Anyone entering must know exactly what procedure to follow in case of emergency. Certainly this is not a facility that can be visited during school trips.
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It is particularly interesting to consider what might happen if a short-circuit affected such a battery system. The batteries are connected in series to each other and their cables are insulated by special plastic sheaths, as shown below.
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A short-circuit of one or more batteries, caused for example by a falling metallic ceiling truss during a collapse, would trigger an electric arc which might have dramatic consequences due to the high currents involved.
As reference for estimates, I consulted data on batteries manufactured by FAAM. Their physical and geometric characteristics are summarized in the following table.
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This table shows that a single battery can weigh from 8 kg (for lower-capacity models with C10 = 100 Ah) to 111 kg (for batteries with C10 = 1500 Ah).
A battery like the ones shown below has a C10 of approximately 400 Ah and can be matched with the FAAM GFM-400 model, which weighs approximately 30 kg (European standards use C10, while American standards use C20).
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The batteries show below have a C10 = 1340 Ah and therefore can be considered as equivalent to a model between FAAM GFM-10000 an GFM-1500, with an estimated weight of 80-90 kg each.
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The short-circuit current that a single battery can deliver is provided by the following table.
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This table shows that a battery with a C10 = 400 Ah releases, in case of a short circuit, 6816 amps, which rise well over 10,000 amps for batteries with a C10 = 1340 Ah. We're talking of currents with thousands of amps, which can produce unimaginable thermal effects.
In addition to this, abundant hydrogen, which is highly flammable, is generated during a short circuit.
A similar system was installed on the 81st floor of WTC2, exactly where the flow of molten material was observed.
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Given these facts, it is very likely that the flow was due to light-alloy aluminum but also to the lead of the batteries, combined with other materials originating from the contents of the 81st floor. This combination of materials, after the failure of the floor, poured onto the 80th floor and from there flowed out from the building face. In my opinion, the weight of the batteries and the weakening caused by the fire on the 80th floor (which compromised the structural capacity of the overlying floor trusses) had an important role in the failure of the 81st floor.
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"date: March 17, 2008 19:23
sender: Michael E. Newman
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Re: Question about UPS in WTC2
Enrico,
modifications were made in 1991 to reinforce the 81st floor of WTC 2 in an area occupied by the United Parcel Service.
Modifications were made in 1999 to floor 81 in an area of the floor occupied by Fuji Bank to accommodate the weight of an uninterruptible power supply.
Both of these modifications are documented in the section of the NIST WTC Investigation Report known as NCSTAR 1-1C (go to
http://wtc.nist.gov/NISTNCSTAR1-1C.pdf).
What is perhaps confusing is that both modifications were made to areas where there are two-way trusses (the corners of the building) and the acronyms (UPS for "United Parcel Service" and "uninterruptible power supply") are the same.
However, these modifications were made eight years apart for two different tenants, so there is no link between them.
I hope this answers your question.
Thank you,
Michael Newman Spokesman, NIST WTC Investigation
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Michael E. Newman - Senior Communications Officer
Public Affairs Office - National Institute of Standards and Technology
100 Bureau Drive, Stop 1070 - Gaithersburg, MD 20899-1070
NIST info at
http://www.nist.gov
NIST news and Tech Beat newsletter at http://www.nist.gov/news
WTC investigation info at http://wtc/nist.gov
****************************************************************"
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I want to thank Mr. Newman and NIST for their clear and kind answer.
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In my opinion it's the first time NIST clearly speaks about an UPS area in the 81st floor of WTC2, so my hypothesis is confirmed by NIST's WTC Investigation.
I think this is a great result for a little Italian blog like "11-SETTEMBRE"!
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See also:
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- NIST confirms "UPS" on 81st floor of WTC2 was power supply; may explain glowing "fountain"
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