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Smoke Management Systems. Federal Building and Fire Safety Investigation of the World Trade Center Disaster.

pdf icon Smoke Management Systems. Federal Building and Fire Safety Investigation of the World Trade Center Disaster. (4068 K)
Ferreira, M. J.; Strege, S. M.

NIST NCSTAR 1-4D; 248 p. September 2005.


World Trade Center; high rise buildings; building collapse; disasters; fire safety; fire investigations; terrorists; terrorism; air flow; building codes; smoke; smoke management; management systems; codes; standards; case histories; systems engineering; effectiveness; evaluation


This report documents the design and installation of the smoke management systems in World Trade Center (WTC) 1, 2, and 7 and compares the designs to the requirements contained in applicable codes and standards. The normal operation of the fully functional smoke management systems in WTC 1 and WTC 2 on September 11, 2001, is also documented. The report provides an overview of smoke management system concepts, discusses the various considerations impacting smoke management system design, and provides a history of the development of smoke control related requirements within various national codes and standards. The report also summarizes the smoke management systems in WTC 1, 2, and 7, and the applicable Building Code of the City of New York (BCNYC) requirements pertaining to smoke management systems for each building. The performance of the installed smoke management systems for WTC 1 and WTC 2 as well as other candidate smoke management system configurations were evaluated using the CONTAM building airflow and contaminant dispersal computer model for specified fire scenarios. These scenarios included the severe aircraft impact related event scenarios that occurred on September 11, 2001, in order to provide a context in which to evaluate smoke management system performance in WTC 1 and WTC 2. The report concludes that the smoke management systems in WTC 1 and WTC 2 were not initiated on September 11, 2001, and had the designed smoke purge sequence been initiated it is unlikely that the system would have functioned as designed, due to loss of electrical power and/or damage to the heating, ventilating, and air conditioning (HVAC) shafts and other structural elements in the impact zone. In addition, none of the potential smoke management system configurations evaluated in this report would have provided sufficient pressure differentials to contain smoke for the postulated aircraft impact damage scenarios, even if these systems were capable of operation after the building sustained damage from the aircraft impact. The report further concludes that stair pressurization would have been ineffective in improving conditions for occupants trying to exit the building.