Hybrid Solutions Group is safeguarding London’s tunnel infrastructure by delivering smarter, safer, and more resilient ventilation systems.
By carrying out planned fan maintenance and introducing predictive monitoring technologies, we’re helping clients extend asset life, prevent breakdowns, and ensure tunnels remain safe for the public and operational teams.
What is the 5 yearly fan maintenance project?
The five-yearly fan maintenance programme involves the systematic inspection, testing, refurbishment, and reinstallation of critical tunnel ventilation fans to ensure ongoing safe operation and compliance with manufacturer and safety standards. At the Rotherhithe Tunnel, Hybrid undertook works on multiple fans, including EF3, SF3, SF4, and SF6. The process included isolating the fans, removing the motor and impeller, conducting Baker tests, overhauling motors, replacing bearings, balancing impellers, inspecting dampers and attenuators, and reinstating electrical connections. Additionally, vibration monitoring systems were installed to enhance future condition monitoring and predictive maintenance.
What are the primary goals of the upgrade?
- To maintain safe and reliable tunnel ventilation by ensuring all fans meet operational standards.
- To prevent unplanned breakdowns through proactive inspection, refurbishment, and replacement of defective components.
- To improve long-term asset resilience by installing vibration monitoring systems for predictive maintenance.
- To comply with statutory safety requirements and TfL/KIER operational standards.
- To extend the service life of critical infrastructure and minimise lifecycle costs.
Why is the project so important?
Tunnel ventilation systems are essential for maintaining air quality, removing vehicle emissions, and ensuring public safety during normal operation and emergency scenarios such as fires. The Rotherhithe Tunnel fans operate under demanding conditions. The five-year maintenance ensures continued compliance with safety standards and provides assurance to stakeholders such as TfL and KIER. During the EF3 works, for example, a motor failure was identified when the unit failed its Baker test. Hybrid promptly replaced the motor with a spare and arranged rewind works for the failed unit, demonstrating the critical role of this programme in preventing prolonged tunnel closures and maintaining public confidence. Furthermore, remedial recommendations such as replacing corroded damper bolts with stainless steel and spot-treating rust help prevent long-term deterioration.
Conclusion
The five-year fan maintenance programme at Rotherhithe Tunnel demonstrates the importance of proactive asset management in complex, high-risk environments. Through comprehensive inspections, testing, refurbishments, and the integration of vibration monitoring technology, Hybrid ensured the continued safe operation of critical tunnel ventilation systems. Despite unforeseen issues such as motor failure on EF3, the project was delivered without delay to the programme. This case study highlights the value of planned maintenance in safeguarding infrastructure, improving resilience, and ensuring compliance with safety and operational standards.
