Office: 9 Residential: 8 Commercial: 3 Combined commercial/residential: 2 The 9-11 events are quite thoroughly documented in the FEMA 4032 and ASCE-SEI Pentagon Reports,3 with further NIST investigations on the WTC ongoing, and will not be further covered herein. Rather, some other interesting and more obscure cases of fire-induced collapses will be described. Two large department store fires in Athens, Greece, in 1980 are documented in the paper by Kyriakos Papaioannoa, 1986.4 These fires began at 3 a.m. on Dec. 19, 1980, with arson being suspected as the cause. The Katrantzos Sport Department Store was an 8-story reinforced concrete building. Its fire started at the 7th floor and rapidly spread throughout the building, due to lack of vertical or horizontal compartmentation and the absence of sprinklers. Collected evidence indicated that the fire temperatures reached 1000°C over the 2- to 3-hour fire duration, and the firefighters concentrated on containing the fire spread to the adjacent buildings. Upon termination of these fires, it was discovered that a major part of the 5th to 8th floors had collapsed. Various other floor and column failures throughout the Katrantzos Building were also observed (see Figure 1). The cause of these failures was considered to be restraint of the differential thermal expansion of the structure that overloaded its specific elements or connections. On May 21, 1987, Sao Paulo had one of the biggest fires in Brazil, which precipitated a substantial partial collapse of the central core of the tall CESP Building 2.5 This was a 21-story office building, headquarters of the Sao Paulo Power Company (CESP), after whom the building was named. Buildings 1 and 2 of this office complex were both of reinforced concrete framing, with ribbed slab floors. These two buildings had several unique internal features and contents. Both buildings still retained their original wood forms used for pouring the concrete floor slabs, which were never removed. Low-height plywood partition walls were also used in the interiors. Approximately two hours after the beginning of the fire in CESP 2, its structural core area throughout the full building height collapsed. This collapse was attributed to the thermal expansion of the horizontal concrete T-beam frames under the elevated fire temperatures, which led to the fracture of the vertical framing elements and their connections in the middle of the building, and the consequent progressive loss of gravity load-carrying capacity (see Figure 2). A fire-initiated full collapse of a textile factory occurred in Alexandria, Egypt, on July 19, 2000.6 This 6-story building was built of reinforced concrete, and its fire started at about 9 a.m. in the storage room at the ground floor. Fire extinguishers were nonfunctional, and the fire spread quickly before the firefighters could arrive. An electrical short-circuit accelerated the fire spread. At about 6 p.m., nine hours after the start of the fire, when the blaze seemingly was under control and subsiding, the building suddenly collapsed, killing 27 people. Figure 3 shows a photograph of this collapse. CONCLUSIONS Past experience and this 2002 NIST collapse survey confirm that fires, and the related damage, deaths, casualties, and any collapses, are essentially rare and random events, whose effects depend highly on the time, nature, and circumstances of the fire occurrence. Thus, fires represent a hazard to all building types, materials, and occupancies. Likewise, the added fire-fighting difficulty in all taller buildings must be recognized, given the longer times needed to escape or access the higher floors. Many of the past major fires in tall buildings fortunately occurred in the evenings or weekends, when the office buildings were almost vacant, thereby, minimizing their potential dangers to human life. Automatic sprinkler systems are a very effective means to suppress a fire, but if the system is being repaired, or is nonexistent or nonfunctional for other reasons, the threat of fire growth increases. Another important finding of this study was the lack of readily available, and well-documented, information on partial or total structural collapse due to fire. Unless the fire event was significant for other reasons, e.g., loss of life, very little information was available. It is recommended that a centralized database be developed, whereby structural damage and collapse can be investigated and systematically reported in the future. The current lack of systematic information on fire-induced collapses seriously limits the profession's understanding of the scope and nature of the real structural fire protection problem. Jesse Beitel and Nestor Iwankiw are with Hughes Associates, Inc. REFERENCES Iwankiw, N., and Beitel, J., "Analysis of Needs and Existing Capabilities for Full-Scale Fire Resistance Testing," Hughes Associates, Report NIST GCR 02-843, December 2002. 2 FEMA 403, World Trade Center Building Performance Study: Data Collection, Preliminary Observations, and Recommendations, Federal Emergency Management Agency, Washington, DC, May 2002. ASCE-SEI, The Pentagon Building Performance Report, ASCE, Reston, VA, January 2003. Papaioannoa, K., "The Conflagration of Two Large Department Stores in the Centre of Athens," Fire and Materials, Vol. 10, 1986, pp. 171-177, John Wiley and Sons, Ltd. Berto, A.F., and Tomina, J.C., "Lessons From the Fire in the CESP Administration Headquarters," IPT Building Technologies, 1988, Sao Paulo, Brazil. BBC News, "Factory Fire Kills 15 in Egypt," World: Asia-Pacific, July 20, 2000.
Nice to hear that the buildings in Athens, Greece...Cairo, Egypt...and Sao Paulo, Brazil are built to the same engineering specs, material specifications, etc. and inspected by inspectors to the same degree that Building 7 was subjected to. Further steps to complete our country's trajectory toward third world status.... Seriously, without knowing the date of the buildings were built, materials used, structural analysis of the method of construction, etc. this study is of little worth...not much more than an apples to oranges analogy. Not a supporter of the conspiracy or against it, I am agnostic on this stuff...just a casual observer noticing how weak the article is its detail if used to combat the Building 7 collapse. Oh, and I found this conclusory statement from the a product of really, really deep thinking: "Thus, fires represent a hazard to all building types, materials, and occupancies." Gee, fires represent a hazard to all building types, materials, and occupancies? Do the insurance companies who issue fire insurance know this? LOL!
Arnie, from the article and statements of the agency compiling the report for the U.S. Government. These statements come directly from the original article posted on page 1: 'Unlike the twin towers, Tower Seven was not hit by a plane. The National Institute of Standards and Technology, based near Washington DC, is expected to conclude in its long-awaited report this month that ordinary fires caused the building to collapse. That would make it the first and only steel skyscraper in the world to collapse because of fire. And... The National Institute of Standards and Technology has spent more than two years investigating Tower Seven but lead investigator Dr Shyam Sunder rejects criticism that it has been slow. "We've been at this for a little over two years and doing a two or two and a half year investigation is not at all unusual. That's the same kind of time frame that takes place when we do aeroplane crash investigations, it takes a few years." With no steel from Tower 7 to study, investigators have instead made four extremely complex computer models worked out to the finest detail. They're confident their approach can now provide the answers. Dr Sunder says the investigation is moving as fast as possible. "It's a very complex problem. It requires a level of fidelity in the modelling and rigour in the analysis that has never been done before." Other skyscrapers haven't fully collapsed before because of fire. But NIST argues that what happened on 9/11 was unique. Steel structure weakened It says Tower Seven had an unusual design, built over an electricity substation and a subway; there were many fires that burnt for hours; and crucially, fire fighters could not fight the fires in Tower 7, because they didn't have enough water and focused on saving lives.
"Thus, fires represent a hazard to all building types, materials, and occupancies." Gee, fires represent a hazard to all building types, materials, and occupancies? Do the insurance companies who issue fire insurance know this? LOL! ------------------------- I wish author(s) would post this info in the opening paragraph, saves time, I wouldn't have continued reading.