- ClientSouthern Gas Networks (SGN)
- RoleDemolition Consultant and CDM Advisor
- TeamStephen McCann – Mick Daynes
We worked for Southern Gas Networks (SGN) on the gas works site in the historic South Hampshire town of Havant, which makes up part of the Portsmouth Conurbation.
This project involved the decommissioning (desludging and dewatering) and demolition of Gasholder No.6 the former above-ground 3-lift spiral gasholder constructed in 1956.
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.
This site was particularly difficult as the gas infrastructure building that was initially scheduled for demolition was decided to be retained, which resulted in reducing the workable area.
The vessel, measuring approximately 40 metres in diameter, was constructed of steel which varied in thickness at each of the inner layers and 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.