We worked for Southern Gas Networks (SGN) on the gas works site in the ancient Saxon-founded town of Farnborough in Hampshire.

The town is probably best known for its association with aviation, with the town being the home of the world-famous Farnborough Airshow.

This project involved the decommissioning (desludging and dewatering) and demolishing of Gasholder No.2, the former above-ground 3-lift spiral gasholder built in 1957.

The works included the dismantling of the gasholder and associated plant, along with other additional structures occupying the site and the infilling of all pits to leave an overall clear and level site.

The site-specific challenges included the proximity to the A331 dual carriageway and the railway intersecting at the north of the triangular-shaped site giving further stakeholder interest, plus the reduced one-way access via Lynchford Lane.

The vessel, measuring approximately 35 metres in diameter, was constructed of steel which varied in thickness at each of the inner layers. Due to its size and the thickness of the metal, the structure was cut up mechanically using hydraulic shears.

Site overview video:

We were appointed as the CDM Advisor for the project. Our roles included checking the Principal Contractor’s Construction Phase Plan (CPP) and reviewing the Risk Assessment and Method Statement (RAMS) for the project before issuing the Authorisation to commence construction activities.

Throughout the project’s period, we carried out audits which were planned to coincide with the specific phases of the project. Such audits included the CDM compliance audit, a specific environmental audit to ensure the sludge and waste were removed in line with the Environmental Agency’s requirements, and a process-specific demolition audit.

• Review and comment on the Construction Phase Plan and issue a report.
• Review and comment on the Risk Assessments and Method Statement and issue a report.
• Carry out the pre-start CDM site audit and issue a report.
• Carry out the environmental site audit and issue a report.
• Carry out the demolition process site audit and issue a report.