Demolition without disturbance

One of the problems of decommissioning a petrol station in the middle of a town is that you have to get on with the neighbours, who are worried about noise, vibrations damaging their foundations, site traffic, mud on the road and the other things that anyone who suddenly has a major building site next to them has a right to worry about.

These were some of the issues David Plumb & Co had to deal with when demolishing and decommissioning a major duel level service station and car dealership at Kingston upon Thames, as part of a continuing decommissioning contract with Esso.

At ground level, the large site, surrounded by residential properties and small retailers, contained a shop, forecourt and Peugeot and Rover showroom. The basement level contained a large workshop and parts department.

David Plumb’s job was to demolish all the buildings, extract and dispose of all the underground fuel storage tanks, and deal with any contamination on the site.

A total of nine underground tanks had to be extracted. The three of these that were in use when the service station closed comprised a 27,000ltr tank, a 54,000ltr tank and a further 54,000ltr tank that had been divided in two by an internal baffle plate. All these had been temporarily filled with water, to prevent an explosive mixture of petrol vapour and air building up.

Before these tanks could be extracted, the water that they were filled with was pumped out through an oil/water separator, allowing the cleaned water to be safely disposed of down a foul sewer and the oily residue to be sent to a hazardous waste site.

Once the tops of the underground tanks had been exposed by excavation, a large hole was cold cut in the top, so that a well trained operative – wearing protective clothing, breathing apparatus and safety equipment – could go inside and manually scrub it clean. This ensured the metal from the tanks themselves was completely decontaminated, so it could be safely handled at the recycling centre to which it was sent.

The other six tanks, discovered during the preparatory survey, had been disused and filled with inert slurry for years. These comprised five 2,000ltr tanks and one 6,000ltr tank.

All of this demolition and excavation required heavy equipment and inevitably generated noise, vibrations and dust.

“This is something we take very seriously,” said Gary Reeve, David Plumb & Co’s site supervisor, “so we go to a great deal of trouble to ensure the number of complaints we receive are kept to a minimum, and any that we do get are dealt with to everyone’s satisfaction as soon as possible.”

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