Agenda item

Peter Osborne (Cabinet Member for Highways and Transport), Helen Rowe (Head of Highways-Assets) and Whitney Gee (Programme Manager) were in attendance for the item.

1.The Cabinet Member presented the following:

a)    Explained that the proposal concerned the replacement of the ventilation system within Chestfield Tunnel on the A299 Thanet Way. Members were advised that the ventilation system was a safety-critical asset which had reached the end of its serviceable life and required replacement to ensure the continued safe operation of the tunnel.

b)    The Committee was informed that failures within the existing ventilation system during 2024 had resulted in significant disruption to the highway network and had necessitated the implementation of traffic management arrangements. It was further explained that the existing jet fan system had exceeded its expected operational lifespan and that the risk of further failures would continue to increase without intervention.

c)      Members were advised that the preferred solution was the replacement of all 32 jet fans with modern equivalents fitted with angled louvre deflectors and the relocation of Fan 2 within each bank to improve maintenance access to associated lighting infrastructure. Officers explained that this option had been identified as offering the best balance of safety, operational effectiveness, constructability and value for money.

d)    The Committee heard that the estimated cost of the preferred option was approximately £2.8 million and that funding would be met through the Department for Transport Highways Maintenance Block allocation. Members were advised that the option represented a significantly lower cost than alternative solutions which had been assessed during the options appraisal process.

e)    Officers explained that the replacement system would: improve smoke control capability and tunnel safety; increase system reliability and resilience; reduce the likelihood of unplanned closures and emergency maintenance activity; improve access for maintenance works; and extend the operational life of the tunnel ventilation infrastructure.

2.Committee discussion raised the following points:

a)    Members sought clarification regarding the contractual arrangements and whether the works would be delivered on a fixed-price basis. Officers advised that a competitive procurement process would be undertaken through the Council’s existing contractual arrangements. Members were informed that the design work had already been substantially developed, helping to reduce delivery and cost risks. Officers further advised that while some uncertainty remained regarding fixing arrangements within the tunnel structure, overall project risks had been substantially mitigated through the design process.

b)    Questions were raised regarding whether the Equality Impact Assessment correctly reflected the preferred option. Officers confirmed that although one document referenced Option 2A, the preferred solution progressed through the decision report was Option 2B and that this represented the option under consideration.

c)    ) A Member queried whether contractual timescales and potential penalties could be applied in order to ensure timely delivery of the scheme. Officers explained that while contractual mechanisms could be considered, applying financial penalties often resulted in increased tender costs. Members were advised that the preferred approach was to manage delivery collaboratively through robust project management and contract administration arrangements.

d)    The Committee recognised the importance of ensuring that the tunnel continued to operate safely and reliably and supported the proposed investment in replacement infrastructure.

RESOLVED to endorse the proposed decision, namely:

PROCEED with the replacement of the Chestfield Tunnel Ventilation System.

AUTHORISE the associated financial commitment, subject to the completion and approval of a satisfactory commercial business case demonstrating affordability, value for money and compliance with KCC procurement requirements.

DELEGATE authority to the Corporate Director of Growth, Environment and Transport, in consultation with the Cabinet Member for Highways and Transport, to take all necessary actions to implement the decision, including the procurement and award of contracts, subject to approval of the commercial business case.