Smoke Management Systems. Federal Building and Fire Safety Investigation of the World Trade Center Disaster.
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.
Keywords:
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
Abstract:
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.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899