The requirements for temporary tunnel ventilation during construction and fit-out have become much more onerous over the last decade. This is largely due to changes in legislation and best practice for safe working levels of pollutants in tunnels during construction. In particular this has impacted the fitting out stage of tunnel construction, where heavy diesel plant is often required. This paper presents a practical application of the new standards to the construction of a major metro railway. The methodology includes assessment of the volume flowrates required to meet the new standards, design solutions to deliver these flowrates in noise and space constrained areas, and comparison between predicted and measured pollution levels. Construction activities and therefore their ventilation requirements can change on an hourly or daily basis. The paper also looks at ways in which daily planning and calculation of requirements can be modified to maximise the amount of plant operating at any one time, while maintaining safe working levels. This approach enables compliance with strict health standards without imposing major restrictions on the construction programme. It also allows for a reduction in energy consumption by directly linking temporary tunnel ventilation operation to daily or hourly plant movement.
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