SKIERS’ clothing and equipment may have provided the fuel for the inferno
that devastated an Austrian ski train last weekend. At least 159 people died
when the train caught fire in a tunnel on its way to the ski and snowboarding
slopes high above the Austrian village of Kaprun.
The cause of the fire is still unknown, but it spread rapidly because of the
“chimney effect”. The fire sucked in air from the bottom of the tunnel, creating
a fierce draught that fanned the flames. The poisonous fumes that killed so many
of the victims emerged from the top end of the tunnel.
It doesn’t take much of a slope to create a chimney effect—and the
3.3-kilometre-long tunnel has an average gradient of 39°. “The slope would
have had an effect on the spread of the fire,” says Dougal Drysdale, head of
fire safety engineering at the University of Edinburgh. “Even with a 20°
slope you can get a chimney effect.”
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The tragedy has some parallels with the escalator fire at King’s Cross
underground station in London in 1987, which killed 31 people. The escalator
shaft at King’s Cross had a 30° slope. With a steeper slope in the Austrian
tunnel the chimney effect spread the fire more quickly. “It would have been so
fast,” says Alan Beard, an expert in modelling the spread of fires at
Heriot-Watt University in Edinburgh.
The train was only 600 metres into the 3.6-metre-diameter Kaprun tunnel when
fire destroyed it. The closed train doors made escape from the side all but
impossible. Those who survived escaped from the rear coach and walked down steps
into the draught that was fanning the flames above. Those who tried to escape
uphill from the front coach were overcome by fumes.
Every fire needs fuel to burn. At King’s Cross, it was wood from the
escalators, but the Austrian train was only six years old and designed to be
fire-resistant. So what fuelled the fire? “I have a horrible suspicion that the
highest fuel load would have been the skiers’ clothing,” says Drysdale. “Skiing
clothing is highly insulated and unlikely to be engineered to resist
ԾپDz.”
A spokeswoman for the Department of Trade and Industry confirms that ski
clothing and equipment only has to be fit for skiing. It isn’t required to
resist fires.
Another possibility is that grease had accumulated on the track or on the
cable that hauled the train. But Ian Jones of technical consultancy AEA
Technology, who modelled the spread of fire for the King’s Cross inquiry, says
of the Austrian disaster: “There was a substantial megawattage of fire that
created an inferno on the scale of King’s Cross. Where did that large fire load
come from?”
Beard is critical of the lack of adequate escape routes. The possibility of a
fire in the tunnel was predictable, he says. “It raises serious questions about
risk assessment.” He says a risk assessment should have identified the danger,
and provided means to fight the fire and a way to escape.
Drysdale points out that the Channel Tunnel linking England and France has a
service tunnel. When a serious fire overwhelmed a train in the tunnel in
November 1996 the service tunnel helped to get trapped people out and get
firefighters in to combat the blaze.
