Smoke Control and Occupant Evacuation at the World Trade Center.
Smoke Control and Occupant Evacuation at the World Trade
Ferreira, M. J.; Strege, S. M.; Peacock, R. D.; Averill,
Annual Meeting. American Society of Heating,
Refrigerating and Air-Conditioning Engineers, Inc.
(ASHRAE). Proceedings. June 21-25, 2008, Salt Lake
City, UT, 1-8 pp, 2008.
World Trade Center; smoke control; occupants;
evacuation; impact; building collapse; building
construction; stairwells; evaluaiton; systems
preformance; human response; fire fighters; first
responders; damage; management systems; effectiveness;
design fires; scenarios
This paper examines smoke control and occupant
evacuation in WTC 1 and WTC 2 on September 11,
2001focusing on the impact region and above for each
tower. Approximately 2,000 individuals were at or above
the area of impact in WTC 1 and WTC 2 who did not
successfully evacuate. NIST found that the smoke
management (smoke purge) systems in WTC 1 and WTC 2 were
not initiated on September 11,2001. Had the smoke purge
sequence (required by the BCNYC for post-fire smoke
venting) been initiated in WTC 1or WTC 2, it is unlikely
the system would have been capable of operation, due to
damage caused by aircraft impacts. Even if fully
operational, none of the hypothetical potential smoke
management approaches evaluated would have prevented
smoke spread given the damage caused by aircraft impact.
During the events occurring on September 11, 2001 stair
pressurization would have been ineffective in improving
conditions for occupants trying to exit the building due
to the extensive damage to the stair shafts.
Installation of combination fire/smoke dampers in HVAC
ductwork, which was not required in WTC 1or WTC 2 at the
time the WTC was constructed, may have acted to slow the
development of hazardous conditions on the uppermost
floors of the building, but would likely not have had a
significant effect on the ability of occupants to egress
the building due to the impassibility of the exit