EMERGENCY EVACUATION is the toughest issue facing building designers in the wake of the terrorist attack on the World Trade Center, a leading tall buildings expert said last week.
Arup America's chairman Tony Fitzpatrick, who is leading a worldwide investigation into improving tall building safety following the September 11 tragedy, said that introducing effective evacuation procedures in tall buildings was more important than retrofitting with hardened fire materials.
'Management of the evacuation system is fundamental and people in the building need a lot of training, ' said Fitzpatrick, head of the Extreme Events Mitigation Team which expects to make its findings public by the end of the year.
Fitzpatrick was speaking at the Tall Storeys conference at the Institution of Mechanical Engineers last week. He confirmed that computer modelling and a trial evacuation of London's 50 storey Canary Wharf three weeks ago had identified a number of problems with total evacuation.
'We found that just getting everyone out of the building straight away could create more problems because the people where the fire is may not be able to get out and fire fighters can't get in, ' he said. Segmental evacuation procedures would need to be retained, he added.
Fitzpatrick also said that changes in the design of future tall buildings would focus on greater ductility, especially for floors. Concrete, he said, should also be mixed with polypropylene fibres to prevent explosion in a hydrocarbon fire. As temperatures soar to 1,000infinityC the fibres melt, creating space for moisture which, he claimed, would stop the concrete expanding as it did at WTC.
However he raised doubts about using compartmentalisation to stop progressive collapse as he felt that it could compromise evacuation routes. He said that evacuees might be forced to travel outside fire protected escape shafts to reach the next compartment.