Evacuation Chairs Australia

In office buildings around the country, a seemingly ubiquitous sign is drawing more attention these days. It reads, simply, ''Exit.''

After the Sept. 11 attacks on the World Trade Center, workers in tall buildings have wondered how they will escape if disaster -- natural or human-caused -- strikes their workplace.

The swift and unexpected collapse of the towers has safety officials and engineers re-examining evacuation plans and stairway design. The collapse is also bringing attention to novel ideas for escape, some already in limited use and others far afield. They include escape tubes that could be slung outside a window, people-lowering devices outside of buildings, flying platforms that would remove occupants through windows and even individual parachutes as a last resort.

Evacuating other tall buildings in emergencies has always been a challenge. When there is trouble in a high-rise, usually a fire, elevators are the first things shut down for fear people will be trapped by power failure. In most instances, emergency stairs are the only way out. The higher the building, the more difficult and time consuming this route can be, particularly for the injured, the elderly or the disabled.

Jake Pauls, an evacuation consultant from Silver Spring, Md., said stairs would remain the main means of escape from tall buildings because outside fire ladders can reach only 9 to 12 stories. However, he said, many stairway exits need to be improved.

The stairways in the World Trade Center were superior to those of many office buildings, he said, and improvements like better lighting and ventilation installed after the 1993 basement bombing of the trade center helped save lives. Although the death toll of occupants and rescue workers was high, he said, thousands did get out in a relatively short time.

''The World Trade Center appears to have been a relative success story,'' Mr. Pauls said. ''Many of the people who could get out did.''

Mr. Pauls, who studied evacuation of the center after the 1993 bombing, said its stairwells were 56 inches wide, compared with 44 inches in most modern buildings, making it easier for people to come down while firefighters and other rescue workers went up. The tower stairs, like those in most office buildings, could have been improved with such things as continuous handrails with no gaps from top to bottom to aid people descending in poor lighting conditions, he said.

The disabled have special problems with stairway evacuations, but there are special evacuation chairs available to make this easier without impeding the flow of other evacuees, experts said. National surveys indicate that less than a half of 1 percent of the population uses wheelchairs, Mr. Pauls said, but about 3 percent of all people have some difficulty with stairs during evacuations. These include some with asthma, heart and other medical conditions, including hip, knees or back problems, and people with phobias about crowds or confined places.

Evacuation chairs, employ beltlike treads and special braking systems that let an attendant guide a person in the chair down the top of steps at normal walking speed. A problem has been having enough of these chairs and people trained to use them available in high-rises, experts said.

Some people are suggesting supplementing stairway evacuation with methods that offer an escape route outside of buildings, including selling individual parachutes.