- Project Upgrading Peterborough Gas Compressor Station
- Principle Contractor Murphy Group
- Project Lead Hannah Hamilton, Technical Sales
- Key Benefit Multiple excavation support solutions were supplied to the customer for a variety of excavation schemes
Introduction
Murphy Group were asked to take on an upgrade project at Peterborough Gas Compressor Station as part of a major capital delivery programme, which is responsible for constructing most of the National Grid’s gas and electricity transmission assets. The programme will see National Grid replace or upgrade a series of compressor stations on the Gas National Transmission System (NTS). The aim of the project is to bring them into line with strict environmental limits laid down under the Industrial Emissions Directive (IED).
The Huntingdon and Peterborough Compressor upgrade is the single largest capital project currently being undertaken on the gas network. The two sites are part of a network of 64 gas-driven compressors around Great Britain that act as the ‘engines’ of the NTS, making sure that gas is pumped to where it is needed 24/7.
However, legislation to cut emissions of carbon dioxide (CO₂) and oxides of nitrogen (NOx) means that ageing technology must be replaced with newer, low emission alternatives.
As a nationally preferred supplier to Murphy, MGF have experience with supporting them on similar projects, including Huntingdon and Bacton. By working closely with the project teams, MGF are able to ensure that customer demands are met surrounding excavation safety.
The Solution
One of the biggest challenges for Murphy is ensuring the station is not taken offline at the same time as their adjacent site in Huntingdon as both sites are predominantly used for bulk transmission of gas to support extremity pressures in the South East and South West, particularly during winter demand. MGF were able to support the customers’ requirements and meet their expectations to reflect their programme of works by offering multiple temporary works designs for the safe construction of cable draw pits and connecting cable runs.
As not all the individual excavations on the project required bespoke designs, Standard Solutions were offered if the necessary parameters were met. MGF’s Standard Solutions services have provided the benefit of saving time and enabled Murphy to utilise the equipment across the site. However, not all areas of the project were suitable for a Standard Solution, and so specific temporary works designs were engineered; the larger, deeper cable draw pits being just one example.
Part of the project also involved installing a row of 5 x 5 150ID ducts which required a width of 1.6m and 2.0m depth. Ordinarily the only possible solution for such an installation in a shallow excavation like this would have been sheets and walers. Fortunately, in 2020 MGF launched the Utility Trench Box which is specifically designed for this type of application. The 1.95m under strut clearance offered the required room and the 2m high panels were a perfect match for the dig depth.
Due to the large nature of the project, a wide range of excavation support systems have been implemented. To begin with, a 305 Tank Brace was installed on the larger cable draw pits along with ER 750mm Trench Sheets, Manhole Brace and KKD Trench Sheets. Where existing services weren’t present, the implementation of various size manhole boxes, including our 2m and 4.4m manhole base and tops were the perfect solution. A selection of MGF trench boxes, sheets and walers have also been present in the many temporary works designs engineered for this project. All solutions were accompanied with the complete safety set up, ensuring upmost safety in and around the excavations, including ladder access platforms and davit rescue systems.
The method of installing trench sheets is normally dictated by the ground conditions across the site and the presence of existing utilities and includes push and dig, dig and push, slit trench and pre-drive. As these works are on a live gas site, for added safety a dig and push method was the only one considered as to avoid the risk of service strikes.
The Verdict
MGF and Murphy have worked in close collaboration throughout the project, allowing MGF to understand the customers needs and challenges whilst eliminating any admin delays.
By reacting quickly to any last-minute design changes and delivery issues, this saved Murphy from any potential setbacks and offered some peace of mind.
With the project currently ongoing, completion is due in March 2022.
