The first phase of dehumidification process to ward off corrosion is underway on the Severn Bridge has jsut been completed.

The £20m project, funded by the Severn River Crossing and carried out by Laing O'Rourke, involved the wrapping of the main cables in a polymer-based material, which was shrink-wrapped into position.

A de-humidification plant room was built within the bridge and all the components had to be manufactured in sections to enable them to be lowered through the hatch and then built inside.

The dry air is then channeled from the plant room into the main cable to reduce humidity and suspend or delay the amount of corrosion.
 

The system itself was designed and installed by humidity specialist Munters, in conjunction with project consultants Faber Maunsell and Laing O'Rourke.

"The system has been running for two months now and has hit the areas we identified as having the worst corrosion, which is at the lowest area of the cables", according to the project manager, Chris Pope.

Phase 2 of the dehumidification is being done by Lincolnshire based C Spencer and the date for project completion is early 2009.

Source: CN