The impact of Mid Tunnel Vent Shafts on temperature on the Victoria Line
Request ID: FOI-2395-2223 Date published: 23 January 2023
Would you be able to share the methods and theory used and data collected by the engineers to come up with the 1-2 degree figure? And were these TfL Engineers or contacted? could you please provide the operating costs of the fanned MTVS on the Victoria Line?
TfL Ref: FOI-2395-2223
Thank you for your follow up request received by Transport for London (TfL) on 22 December 2022, asking for further information about the Mid Tunnel Ventilation Shaft on the Victoria Line.
Your request has been considered in accordance with the requirements of the Freedom of Information Act and our information access policy. I can confirm that we hold some of the information you require. You asked:
Would you be able to share the methods and theory used and data collected by the engineers to come up with the 1-2 degree figure? And were these TfL Engineers or contacted?
Between 2006 and 2012 tunnel ventilation analysis on the deep tube lines was performed by both TfL engineers and contracted engineers. Since 2012 tunnel ventilation analysis on the deep tube lines has predominantly been undertaken by TfL engineers. Our team of engineers utilise industry best practices and computational fluid dynamic modelling techniques to assess the thermal benefits of ventilation and cooling assets within deep tube environments. These techniques have been applied within many projects and programmes across the LU network and form our general view that benefits are typically between 1degC-2degC. The benefits can vary from location to location and not all vent shafts may fall into this typical range, thus location specific analysis is required if individual vent shafts require assessment.
In addition, could you please provide the operating costs of the fanned MTVS on the Victoria Line?
We do not hold a breakdown of operating costs for this system per line. This is resource based.
In any case, we would not be able to share any costs at this time as we are currently in the middle of a procurement process. Disclosure of this financial information would provide competitors with an unfair advantage during the ongoing tendering process.
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Eva Hextall FOI Case Management Team General Counsel Transport for London