Published in the January 2008 issue of Today’s Facility Manager
(Photo provided by Claymour stock.xchng.com: design by Megan Knight, Senior Designer, Group C)
More than 18,000 people safely evacuated from the World Trade Center complex in the one hour, 42 minutes, and five seconds between when the first jet hit the Towers and the last building collapsed. Those buildings that were destroyed not only included both of the Twin Towers, but also the Marriott Hotel, Six World Trade Center, and the 47 story Seven World Trade Center.
In the immediate two months following the disaster, USA TODAY’s investigative reporters documented the key issues in a special report [“For Many of Sept. 11, Survival was no Accident,” by Dennis Cauchon, USA TODAY, December 20, 2001] which profiled why so many were able to survive this event. These findings reinforced the classic design of emergency planning and business continuity that facility executives inherently understand and now have the ammunition to enforce.
The findings were later validated in The 9/11 Commission Report [The 9/11 Commission Report: Final Report of the National Commission on Terrorist Attacks Upon the United States, 1st ed. (New York, NY: W.W. Norton & Company, 2004), 28-323]. Generally, the evacuation was considered a success: 95% of the people below (and sometimes on) the floors struck by jets survived. Unfortunately, 99% of the people above those floors died, and more than 479 rescue workers also perished in their attempts to fight the fires and evacuate building occupants.
Survival No Fluke
This was not an accident; for as was initially reported in USA TODAY and later validated by the 9/11 Commission [Commission, p. 316], this expeditious evacuation happened because of significant changes made by the Port Authority in response to the bombings at the Towers in 1993, “and by the training of both Port Authority personnel and civilians after that time.”
For example, emergency lighting in the stairwells and corridors was set up on a backup battery power source. (In 1993, the failure of the emergency lighting was a major problem in the evacuation.) The lights in the stairwells were also re-designed in modular sections; so if one section failed, the other sections stayed on (like Christmas trees). The lights were functioning on the lower levels of the Towers, even as the top floors were collapsing.
Evacuation drills were held every six months, and each floor had fire wardens responsible for the organization of evacuation plans for their floor. These wardens played a crucial role on 9/11, as they literally pushed and pulled people out of the buildings and searched the floors to ensure that everyone had left.
The Commission Report [p. 316] stated, “The general evacuation drill time for the towers dropped from more than four hours in 1993 to under one hour on 9/11 for most civilians who were not trapped or physically incapable of enduring a long descent.” This was a critical time difference, as the South Tower only stood 56 minutes from impact to collapse.
Stairwells To Safety
One significant aspect of the building layout did aid in the evacuation of thousands of people—the stairwells. Designed to a much higher standard than other structures built according to code 30 years ago, the Towers had three evacuation stairwells instead of the minimum of two. In addition, the center stairwell in both Towers was 56″ wide instead of the code required 44″ on the two corner stairwells. This allowed two people to move down these stairs side-by-side and permitted the firefighters to pass without stopping the downward flow of occupants.
The situation could have been even better; in late May of 2007, the International Code Council approved new codes for skyscraper safety requirements, implying that “tall buildings nationwide could soon be required to be designed with an extra emergency stairwell [key to the evacuations on 9/11] and more robust fireproofing….At least one elevator in buildings at least 120′ tall would also have to be specially built with backup power systems and fire resistant wiring so firefighters could use it reliably in emergencies.” [“Safety Group Proposes Third Stairwell in High Rises” by Eric Lipton, New York Times, June 23, 2007.]
As reflected in these code improvements, the elevator system at the Towers was another hero of 9/11. The system, redesigned and enhanced by Otis Elevator after the attack in 1993, was one of the biggest and fastest in the world.
Room sized express elevators moved thousands from the lobby on the 78th floor to the ground in 45 seconds. Each of the 12 elevators held 55 people. So every two minutes, 500 people were moved down and ultimately out of the Towers. [Cauchon, USA TODAY.]
More Work To Be Done
The one serious flaw in the improved planning was the lack of a set of as-built drawings in each of the fire command centers and in a nearby off site location. This omission delayed search and rescue efforts and cost lives.
The Commission [p. 318] also noted that “individual citizens need to take responsibility for maximizing the probability that they will survive, should disaster strike.”
Overall, good design and excellent emergency planning made an enormous difference on 9/11. Facility executives have long understood this critical relationship.
The principles of all emergency plans are the same, regardless of the location. The best plan is one that is comprehensive and understandable. It must involve the personnel of the company at every level and be easily understood by all employees, even those who have been with the company just a short time. It must consider the full range of potential disasters at all company locations, even if the probabilities of particular disasters such as earthquakes in London or tornadoes in northern Australia are fairly low. Last, but certainly not least, the emergency plan must be maintained, updated, and changed as necessary.
Simply put, it is the installation of a new long life metal roof over an existing metal roof in a way that is structurally correct, non-disruptive and cost effective. It is a system that adds strength, is environmentally friendly, cooler in summer, warmer in winter and conserves energy.