High profile evacuation

Those buildings that were destroyed not only included both of the Twin Towers, but also the Marriott Hotel, Six World Trade Centre and the 47-storey Seven World Trade Centre.

In the two months following the disaster, Dennis Cauchon, an investigative reporter for USA Today, documented the key findings that profile why so many were able to survive this event. These findings reinforce the classic design of emergency planning and business continuity that facility executives inherently understand, and now have the ammunition to enforce.

The key findings were:

· The evacuation was a success. While 99% of the people above the floors struck by the jets died (above the 91st floor in the North Tower, and above the 77th floor in the South Tower), 99% of the people below (and sometimes on) those floors survived. More than 479 rescue workers also died in their attempts to fight the fires and evacuate building occupants.

· After the bombing of the parking garage in the North Tower in 1993, a number of improvements (as follows) were made to the exit routes to enhance the opportunity to get out of the building, if necessary:

- Reflective paint was added to all exit doors, stairs, railings, and bright arrows were painted along exit corridors to guide people in the event of poor visibility.

- A building-wide speaker system was installed to be able to talk to people in the exit locations.

- Every disabled person was given an evacuation chair to enable people to carry them down the stairs; one such chair was used to carry a man down from the 67th floor.

In 1993, the explosion knocked out the main power source, its backup and the fire-control command post. The Port Authority (public owner of the complex) added a second source of power for safety equipment, such as the fire alarms, the emergency light, and intercoms. It built two duplicate fire-command posts, one in each tower. (It should be noted that the one serious flaw in the improved planning was the lack of a set of as-built drawings in each of the fire-command centres, and in a nearby off-site location. This made search and rescue operations very difficult initially.)

Emergency lighting in the stairwells and corridors was also set up on a backup battery power source. The lights in the stairwells were also designed in modular sections; like Christmas tree lights, if one section failed, the other sections stayed on. 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, who were responsible for the organisation of evacuation plans for their floor. These wardens played a crucial role on September 11, as they literally pushed and pulled people out of the buildings, and searched the floors to ensure that everyone had left. People knew where the stairs were located for their floors, and had already experienced what it is like to walk down 70 floors of stairs and how long it takes to reach the ground floor.

The building design also aided in the evacuation of these thousands of people, especially the stairwells. Designed much better than required by the building codes 30 years ago, the towers had three evacuation stairwells, instead of the minimum of two. In addition, the centre stairwell in both towers was 56 inches (1.42 m) wide, instead of the code-required 44 inches (1.18 m) on the two corner stairwells. This allowed two people to move down these stairs side-by-side, and allowed for the firefighters to pass them without stopping the downward flow of occupants.

Last, but certainly not least, the elevator system became a hero of the day. 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; every two minutes 500 people were moved down and ultimately, out of the towers.

Thus it is clear that both good design, and excellent emergency planning made an enormous difference on September 11. What facility executives also know is that the principles of an emergency plan are the same irrespective of the location.

The best emergency plan is one that is comprehensive and understandable. It must involve the personnel of the company at all levels, 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.

Edited version of a paper, September 11: a new meaning and the lessons learned, presented at Ideaction 2002, 13th National Conference of the Facility Management Association of Australia, 8-10 May 2002. Hardy is Associate Professor at Ferris State University, Michigan.

Source: SPECnews #31 Spring 2002, www.natspec.info