Looking for an answer

A UK team is to conduct the biggest-ever survey of the World Trade Centre survivors in bid to improve high-rise building standards and design.

UK researchers will carry out the biggest study of World Trade Centre survivors in an effort to help structural engineers and architects design safer skyscrapers.

A team from three UK universities plans to interview over 2,000 people who escaped the WTC to discover how the evacuation of September 11 unfolded, and which elements in the twin towers’ design helped or hindered their escape.

While several major studies are underway into the structural issues of the WTC disaster, the implications of evacuating thousands of people from the buildings have received less attention. The UK team hopes the data will shape building standards and design for future high-rise structures around the world.

The lead researcher, Prof Ed Galea of the Fire Safety Engineering Group at the University of Greenwich, has already claimed that better staircase design could have saved more than 1,000 lives, and that the death rate would have been far higher if the WTC had been fully occupied (see sidebar below).

The new three-year project, called Heed (High-rise Evacuation Evaluation Database) will bring together fire engineering expertise, including the use of advanced fire and evacuation simulation software, and psychologists.

The latter will play a crucial role in extracting useful data from the survivors, many of who are still likely to be traumatised by their experience.

Funded by a £1.6m grant from the UK’s EPSRC, Heed is made up of researchers from Greenwich, Ulster University’s Faculty ofEngineering and the Centre for Investigative Psychology atLiverpool University.

The project team has reached an agreement in principle with the New York Health Department to gain access to its database of WTC survivors.

If enough agree to take part, it will conduct face-to-face interviews in an effort to build up a detailed picture of exactly what took place inside the towers as thousands tried to escape the doomedbuildings.

Galea said the responses could provide valuable insights into how people behaved in the midst of the greatest disaster ever to strike a high-rise structure.

‘We are trying to learn lessons that will be highly relevant to building codes and standards, high-rise building design and evacuation procedures,’ said Galea.

‘Among other things, we will be looking for an indication of how quickly people responded. Did they try to obtain additional information about the emergency? Did they try to use the elevators? Did they move in groups or alone? How did disabled people in the buildings respond?’

Galea said the scale of the study should deliver far more comprehensive data than any attempted so far, including one carried out by Greenwich itself on behalf of the UK government and the official investigation of the US National Institute of Standards and Technology.

While offering useful pointers, Galea said these have had to rely heavily on published accounts of survivors mainly drawn from newspapers, with only a limited attempt to gather first-hand data. ‘The printed accounts can be unreliable,’ said Galea.

‘We don’t know what questions the survivors were asked and how accurately their responses have been reported.’

SIDEBAR: How Exodus revealed exit flaws

More than 1,000 people trapped in the World Trade Centre’s north tower (WTC 1) could have escaped if better building design had kept just one staircase open, according to Greenwich University’s fire engineering team.

About 1,400 people were marooned above the 91st floor of WTC 1 when the impact severed all three emergency staircases, which were located close together in the core of the building.

The Greenwich team, led by Prof Ed Galea, recreated the disaster with its Exodus evacuation simulation software, used to model emergency scenarios.

It suggested that if only one staircase had survived there would have been time to get the majority of those above the impact zone out before the tower collapsed.

Galea said the simulation raised questions over the decision to place all the emergency staircases so close together.

He also called for structural engineers to ensure that emergency staircases in tall buildings were as robust as possible to give them the maximum chance of surviving catastrophes.

The staircase simulation is an example of the kind of lesson Galea and his team hope will emerge from the new Heed project and a smaller study carried out for the UK government, the results of which will be unveiled this autumn.

Galea has already warned that the fact that almost everybody below the aircraft impact line was successfully evacuated should not be a cause for complacency.

The building was less than one third full. An Exodus simulation of the evacuation with a full complement of 25,000 people inside – and removing those above the 90th floor from the equation – suggested that more than 1,500 would still have been stuck on the stairs when the tower collapsed.