Civil engineering company Spencer has been appointed to carry out major dehumidification works on the Severn Bridge, which links England and Wales. The US$9 million contract follows a similar project currently under way to dry out the cables on the Forth Road Bridge.

The latest contract is part of the Highways Agency's US$41 million contract with Severn River Crossing plc to preserve the bridge following the identification of significant corrosion last year.

Drying out of the cables is intended to slow down further corrosion. Work on the main cables will start in February. The whole of each cable will be wrapped with an airtight membrane, with air inlet and outlet sleeves at various locations. Dehumidification units will pump warm, dry air through the cables, reducing the relative humidity of the air within the cables to 40%.