TUNNEL WORKERS forced to go through a 60 degree temperature change twice a day are to benefit from a specially-constructed 'heat stress chamber' in an attempt to protect them from developing life-threatening health problems.
The chamber is being built as part of preparatory works for the 57km long Gotthard tunnel project in Switzerland. Workers will use it to acclimatise for more than an hour at the start and end of shifts, in the same way that divers might use a pressure chamber.
'Tunnel face conditions will involve working at 28degreesC,' explained Werner Beerle, spokesman for the AlpTransit company in charge of the project. 'But in the mountain valley where the access to the shaft is located, winter temperatures could drop to below -25degreesC.'
The tunnel will run at a depth of up to 2km and temperatures are expected to reach a maximum of 45degreesC to 48degreesC, though tunnel works will be cooled by refrigerated air plant.
Dr Kamran Abbassi of the British Medical Journal said that extreme changes in heat would disturb the body's temperature regulatory system, possibly affecting vital organs such as the heart, and altering the blood flow to the brain. He added that little research had been done into the potential effect of such great temperatures swings, but said: 'Without the heat stress chamber, it could be like getting heat- stroke and hypothermia on every shift.'
The Gotthard project will provide the 'base tunnel' for a major high speed rail link through the country from Zurich to Italy. Work on the shaft, designed to provide access to one of the main tunnelling points, began this summer at Sedrun.
Construction of the main twin bore tunnel, and several smaller tunnels, is expected to begin in earnest next year. But the much delayed project has first to pass through two funding referenda this autumn. The government proposes using a new lorry tax to help with the funding.