[cdn-nucl-l] Reply from G. Charles Clifton

["Dukelow, James S Jr" <jim.dukelow@pnl.gov>]

As I noted in an earlier message, I asked G. Charles Clifton, whose white
paper was one of the references cited by Andrew Schlafly as supporting his
assertion that lack of asbestos insulation had accelerated the failure of
the WTC towers, if he still believed, after the report of the official
inquiry, that the towers failed due to the initial jet liner impact, not due
to the resulting fire.  I received the following response, which Clifton has
graciously allowed me to forward to Can_Nuke.

The attached files that he refers to amount to approximately 3 MBytes.  I
will be happy to forward them to anyone interested.

Best regards.

Jim Dukelow
Pacific Northwest National Laboratory
Richland, WA
jim.dukelow@pnl.gov

These comments are mine and have not been reviewed and/or approved by my
management or by the U.S. Department of Energy.

============================

Dear Jim, 

  I am attaching the latest versions of the papers that I have written on
the collapses as well as a pdf version of a powerpoint presentation that   I
gave to one of our Professional Engineers branch groups in July. The    FEMA
report does not change anything of substance in those papers - the only
point I missed was the region of high fire severity in the North East 
  corner of the South Tower in the impact floors due to the accumulation of 
  material from the plane and building contents that were forced into that 
  corner from the impact. This meant that the perimeter frame on the East 
  side was attacked at the North end of the East side by this fire, while 
  having been severely damaged at the South end by the impact. The combined 
  effect offers a logical explanation as to why collapse of the South Tower 
  was initiated by a buckling failure of the perimeter frame along the East 
  side. This is picked up in the IPENZ talk slides. 

  Yes I am still of the opinion that the primary cause of the collapses was 
  the initial impacts. If the Towers had been subjected to fires of the same

  intensity acting on an undamaged structure they would not have collapsed. 
  Given the damage of the initial impacts, however, it is my strongly held 
  opinion that the type of passive fire protection material applied (of all 
  the materials that are or have been available to use on buildings) would 
  have made little if any difference to the survival time of the towers. If 
  the columns had been protected with one of the products used in the 
  offshore oil industry this might have increased the survival time and if 
  the columns, especially the core columns, had been concrete filled this 
  would have increased the survival time of the North tower. However the 
  difference between the use of asbestos type protection versus its 
  replacement type as specified in buildings would have been negligible. 

  I am happy for this email and the attachments to be circulated to the 
  internet discussion group. 

  Regards, 
  Charles. 

  Charles Clifton, 
  HERA Structural Engineer, 
  PO Box 76-134, 
  Manukau City, 
  Phone + 64 9 2622885 
  Fax    + 64 9 2622856 
  Email structural@hera.org.nz 



  -----Original Message----- 
  From:   Jim Dukelow [SMTP:jim.dukelow@pnl.gov] 
  Sent:   Saturday, 31 August 2002 6:05 a.m. 
  To:     structural@hera.org.nz 
  Subject:        Your white paper on the collapse of the WTC towers 

  Dear G. Charles Clifton: 

  Your white paper is being used by Andrew Schlafly, an American lawyer, 
  as support for his argument that removal of asbestos insulation from the 
  WTC towers was responsible for the collapse.  He is reported (by Jerry 
  Cutler, a Canadian nuclear engineer who was a speaker at the same 
  meeting) to have said: 

  quoting Jerry, "He said that the asbestos ban came into force during 
  construction of the WTC, at the ~50 floor of the first building.  There 
  was no time to design and procure an alternate thermal barrier to 
  replace the asbestos fire protection around the steelwork.  The asbestos 
  was deleted because of the concerns expressed about potential adverse 
  health effects, due to potential exposure to this asbestos.  Andrew 
  indicated that, had the asbestos been installed, it would have delayed 
  the collapse of the two burning buildings by several (~3?) hours.  This 
  extra time would have allowed just about all of the people of the WTC to 
  escape." 

  Subsequently, in a message to the same Internet discussion group, 
  Schlafly wrote: 

  "A ceramic substitute for asbestos was used, but it was not nearly as 
  effective in protecting buildings against fire as asbestos is (almost 
  nothing is)." 

  My reading of your white paper is that you express both caution due to 
  writing only a few days after the event and a strong opinion that the 
  WTC tower failures were due to the aircraft impacts, not the fires.  You 
  presumable still held that opinion in mid-December when the white paper 
  was last revised. 

  I was wondering if you still hold that opinion, after the publication of 
  the report of the official inquiry, which tentatively, but pretty 
  strongly, ascribes the failure to the structural weaking caused by the 
  fires. 

  If you choose to respond, I would appreciate knowing if you mind having 
  your response forwarded to the Internet discussion group hosting this 
  discussion/argument. 

  Best regards. 

  Jim Dukelow 
  Pacific Northwest National Laboratory 
  Richland, WA 
  jim.dukelow@pnl.gov