Arundel Gate Heat Network Upgrade
Project Location:
City Centre, Sheffield
Client Name:
Veolia Environmental Services UK

Delivering complex works in a confined space tunnel
Maintaining the integrity and safe operation of a live DN400 district heating network throughout the intervention
Restricted access and limited working area, creating significant constraints for lifting, welding and installation activities
Modifying existing flow and return mains to resolve thermal expansion deficiencies not addressed in the original design
Managing night-time isolations and shutdown sequencing to minimise disruption to network operation and wider stakeholders
Challenge
Project Description:
Veolia Environmental Services UK undertook a programme of heat network resilience upgrades across the city to strengthen existing infrastructure and enable future connections.
At Arundel Gate, Valmech, part of OCU Group, was appointed to deliver the specialist supply, installation,
testing and commissioning of DN400 Series 1 UDHN pipework. The scheme required complex intervention within a live district heating network located approximately 6 metres beneath a principal city centre carriageway.
Installed four DN400 pre-insulated isolation valves upstream and downstream of the tunnel section to strengthen control and future maintainability
Implemented a safe sectional isolation strategy, enabling removal and modification of the existing DN400 flow and return mains
Reconfigured pipework layout to incorporate appropriate thermal expansion allowances and reduce long-term asset stress
Delivered confined space welding, installation, testing and commissioning under strict safety procedures and permit controls
Solution
Key Stats:
DN400 Series 1 UDHN pipework installation, testing and commissioning
Four 4 x isolation valves
6m deep tunnel
Confined space works
Modification of existing mains
Successfully upgraded a critical section of Sheffield’s district heating network within a highly constrained tunnel environment
Improved network resilience and reduced long-term asset stress through reconfiguration that allows controlled thermal movement
Enhanced isolation capability, enabling safer and more efficient future maintenance and emergency response
Fully tested and commissioned installation returned to service with no compromise to operational performance
Strengthened delivery of Veolia’s wider city-wide heat network upgrade and future connection strategy
Outcome
3 Years
Duration

