David W. Dunlap NY Times
“In case of fire, use elevators.”
It sounds like apostasy, as if a lifetime’s indoctrination had suddenly been invalidated.
But it is exactly the instruction that office workers in New York’s tallest skyscrapers may receive in coming years. The Fire, Buildings and City Planning Departments are writing rules to govern what are called occupant-evacuation elevators — cars that can, in special circumstances, be used to move people down in an emergency.
Four World Trade Center and 1 World Trade Center, left. The terrorist attack on the twin towers in 2001 was one of two big events that set the stage for a sea change in evacuation philosophy. Credit Karsten Moran for The New York Times
That would upend decades of codes and practices based on the notion that elevators are perilous and undependable in fires or other emergencies. Experts who have spent years studying building evacuations believe that approach has become outmoded and is in itself potentially dangerous as extremely tall skyscrapers increasingly pierce the New York skyline.
“We have to find a better way to evacuate people from high-rise buildings, including people with disabilities,” Edward T. Ferrier, the deputy assistant chief of fire prevention, said. He added that the Fire Department’s attitude about occupant-evacuation elevators was “positive.” Though there are none in New York, they have been installed in a number of towers overseas.
“They’re really for the expedient evacuation from endangered floors to a safer location until the arrival of the Fire Department,” Chief Ferrier said.
Though years in the making, the change feels like an abrupt about-face.
“In the 1970s, a number of fatalities occurred in high-rise building fires where people were trapped in smoke-filled hoistways or taken to a floor where a fire was active,” Brian Black, a codes and standards analyst for the National Elevator Industry, a trade association, wrote in a newsletter published Tuesday.
By the late ’70s, elevators were required to return automatically to the main floor and be taken out of passenger service if smoke was detected in an elevator hoist way, lobby or machine room, or if a sprinkler alarm went off. Warning signs proliferated: “In case of fire, use stairs unless otherwise instructed.”
Underscoring public anxiety were real-life stories of passengers trapped 500 feet above ground in an elevator shaft at the World Trade Center and Hollywood images of deadly elevator evacuations. It remains to be seen how easily people can be coaxed into elevators during emergencies.
“It will take a lot of education, and everybody recognizes that,” said Jeffrey Blain, the manager of destination products at the Schindler Elevator Corporation, the contractor for several projects at the World Trade Center, which is now testing and developing occupant-evacuation features.
Some requirements that the city is expected to impose for evacuation elevators have been anticipated in elevators at 3 and 4 World Trade Center. The floors in front of the elevator doors are raised slightly, to protect the hoistways from water from sprinklers or firefighters’ hoses. The capacity of the emergency generators was increased to provide uninterrupted service to those cars. The cars stop at every floor. Hoist ways are within cores protected by reinforced concrete walls at least 18 inches thick.
All three service elevators in 4 World Trade Center can be used for occupant evacuation. Credit Joe Woolhead
Two big events — the passage of the American With Disabilities Act in 1990 and the terrorist attack on the twin towers in 2001 — set the stage for a sea change in evacuation philosophy.
“The Americans With Disabilities Act requires that we provide access to the workplace for people with disabilities,” said Jason D. Averill, chief of the materials and structural systems division of the National Institute of Standards and Technology. “We provided elevators to get them into the building. But we didn’t turn around and provide them with equal egress.”
In its final report on the collapse of the towers, the institute said that about 1,000 occupants faced problems using the stairs for reasons that included obesity, pregnancy and age. “The most frequently reported disabilities were recent injuries and chronic illnesses,” the report stated. “The fraction of occupants requiring use of a wheelchair was very small.”
Elevators played a lifesaving role on September 11, 2001, especially for occupants of 2 World Trade Center, who knew — by sight, sound and word of mouth — that something horrendous had just occurred at 1 World Trade Center.
“Approximately 3,000 people escaped because of the actions they took in the 16 minutes following the aircraft impact on WTC 1, especially their use of the elevators,” the institute concluded in its report. That is about as many people as were killed.
A long review of codes and standards was begun by the American Society of Mechanical Engineers. Those recommendations were reviewed by city officials and will be incorporated into the city’s new building code, Chief Ferrier said. That code is based on the International Building Code, which serves as a kind of template for local jurisdictions to use, with modifications as needed.
The thrust of New York’s regulatory effort now is the provision for what is called the “third stair” in commercial towers higher than 420 feet, or about 40 stories. Builders of new commercial high-rises must furnish one more means of emergency exiting than the typical two stairways.
On Wednesday, the City Planning Commission is expected to approve a measure that would allow developers to satisfy this requirement by providing an extra stairway (which would not be counted against the square footage they are allowed to build), by providing wider stairways (the extra width would not be counted) and some occupant-evacuation elevators, or by making all elevators comply with occupant-evacuation standards. If passed, the measure will go to the City Council.
In addition, the Buildings Department is drafting rules for occupant-evacuation elevators, an agency spokesman said, in consultation with the Fire Department.
Residential high-rises are not addressed in the new rules for a number of reasons, including the fact that office buildings were the chief focus of concern after the destruction of the trade center. Also, apartment building floors are usually much smaller than those in commercial buildings, there are far fewer occupants on a floor than in office buildings or hotels, and occupants are more familiar with their building.
At the trade center, all three service cars and certain passenger cars in the newly opened 4 World Trade Center can be used for occupant evacuation. So could four service cars at 3 World Trade Center, now under construction. “It was an idea we put into place even before the code was adopted,” said Serge Demerjian, the development manager at Silverstein Properties, the builder of the two towers.
Glenn Corbett, an associate professor at the John Jay College of Criminal Justice whose expertise is fire safety, said that the notion of occupant-evacuation elevators was a reasonable one.
“It’s pretty clear to a lot of us, as we go higher and higher with high-rises,” he said, “that expecting people to walk all the way down is unrealistic.”
