Northern Line Ventilation

Under-platform ventilation for the Northern Line Extension – Keeping Commuters of South London Cool

The Transport for London Northern Line Extension (NLE) project will provide significant ventilation at its new train stations. Air Tightness Solutions was appointed to assist in providing optimal ventilation performance at Battersea Power tube station.

The prestigious NLE project was handed over to Ferrovial Agroman and Laing O’Rourke (FLO), the same contractors whom achieved industry-leading safety results as HETCo for the new Terminal 2A at Heathrow Airport. We were delighted to work with FLO to identify the air leakage performance of blockwork wall that forms the dedicated ventilation shaft of the under-level platform of Battersea power tube station.

After temperatures reached 26°C on the tube network in the summer of 2017, heat extraction and occupier comfort became a central point in improving the London Underground service. The ‘Cooling the Tube’ programme, on going since 2008, involves techniques such as pumping fresh air across temporary fans to increase ventilation across platforms. It is understood that more than half the heat in the tunnels comes from train brakes and its motors; drawing away hot air at station platform reduces heat dumped into the tunnels as the trains exit.

However, record temperatures still reached a whopping 40°C in the tube network over the summer of 2018 and therefore the air conditioning of the new NLE tunnelling systems is a focal point in increasing heat reduction.

The new NLE tunnels will provide a large amount of airflow ventilation by utilising an under-platform air system at Battersea Power tube station. A blockwork wall forms an integral part of this airtight ventilation shaft. Air Tightness Solutions has provided the air permeability performance of four different treated samples of blockwork.

The test method comprised of an airtight plenum chamber being attached to each of the four individually treated samples. A fan and flow-measuring device were used to determine the air leakage performance of each sample.

FLO were delighted with the findings provided and Air Tightness Solutions are delighted to have the opportunity of working with FLO again in the near future on the remaining NLE project which is due to be opening in 2020.

Author: Jashan Goodary, Acoustic Engineer 

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