The Challenge:

The city of Derry is rapidly expanding with new housing, so the current single 250mm gas main – which supplies around 10,000 domestic and business customers – needed reinforcing to ensure supply continuity and to create a ring main system around Derry.

FE needed a four-bar gas main across the River Foyle to provide the city side of Derry with a secondary, back-feed supply pipe.

The Solution:

The project included many stakeholders, and communication with them was key to its success. This included:

  • Consultation with Northern Ireland Water regarding trunk mains laid on the riverbed.
  • Liaison with Northern Ireland Railways regarding the pipeline crossing under the live Belfast-Derry rail line.
  • Consultation with DAERA regarding the marine environment and associated licences.
  • Regular conversations with residents, businesses – including the new Thornhill School – and the roads service.
  • Site visits with the engineering community in Northern Ireland, nearby schools and other stakeholders.
  • Regular noise monitoring including first ever marine noise monitoring.

When we were appointed as main contractor, we selected a specialist HDD subcontractor, McCormack & Sons Directional Drilling, a local company with a proven track record in this kind of complex work. Innovation was fundamental to the project’s success. This included:

  • A bespoke 355mm SDR7.4 PE100 pipe, specially manufactured for this project.
  • Onsite laboratory testing and adjustment of drilling fluids during HDD operations e.g.: viscosity and specific density.
  • Provision of a specialist drilling fluid engineer from the oil industry in Scotland, and a full-time member of the McCormack drilling team on site.
  • Use of Thornhill school for the PE butt fusion of the 355mm diameter PE pipe string and use of Trakway temporary road system within the school.
  • A state-of-the-art GYRO guidance system for use during the pilot bore HDD drilling operation
  • A 600mm duct across and under the Culmore Rd to mitigate disruption during pipe string movement and pipe pulling operations
  • A picture of the River Foyle on hoardings to mitigate the visual impact to residents at Owenmore Place, Strathfoyle estate


The Impact:

The construction phase of the project was completed in 10 weeks and has recently been nominated for a prestigious Network Award, which celebrate the very best in UK energy networks, supply chains, and wider industry stakeholders.

The project team was committed to helping the local community, including raising money for the Foyle Hospice through the sale of project calendars, recycling and reusing drilling fluids from both sides of the crossing, and talking to students at local schools about career opportunities in science, technology, engineering and manufacturing.

" Many thanks for all the work put into the Foyle Crossing. The commitment and teamwork have been clear from the start from all involved. The installation of the main under the river and the works has been a credit to you all. It is easy to forget the enormity and complexity of the project when it has been in planning for so long and we have been so close to it, but this is such a prestigious project and one we should all be very proud of. Thank you again for your professionalism and support in delivering this project for firmus energy. "
Eric Cosgrove Director of Engineering firmus energy
The River Foyle Crossing

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