Milestone Achieved: Central Tunnel of Central Kowloon Route Project Completed – World's Largest Tunnel Air Purification System!

By Charlene Zhang | AirQuality Business Manager

After five years of relentless dedication, we are proud to announce the completion of the 2.8 km dual 3-lane tunnel lining for the Central Kowloon Route -- Central Tunnel project! This monumental undertaking involves extensive tunneling, the utilization of five purpose-built lining shutters, and the application of over 330,000 m³ of concrete. The project also posed unique challenges, including working beneath more than 450 buildings, various infrastructure elements, and four operational underground lines.

The 2.8 km-long Central Tunnel is a key component of the Central Kowloon Route. Once operational, it will significantly reduce travel time between West Kowloon and Kowloon Bay from 30 minutes to just 5 minutes, alleviating traffic congestion in the Kowloon East area.

The Central Kowloon Route (CKR) features the world’s largest Air Purification Tunnel, equipped with nine Air Purification Systems (APS) located across three stations: YVB, KVB, and HVB. Together, these systems have a combined capacity of 2,250 m³/s of air volume. This extraordinary APS was provided by Clean Tunnel Air International AS(CTA).

The CKR APS employs shaft-based installation, which forces polluted air into the APS for purification. The treated air is then discharged to the surface through the shaft. Typically, a shaft air treatment station is installed at a specific distance before the tunnel exit. The entire system comprises a Mechanical Pre-Filter, Vortex Electrostatic Precipitator, NOx Gas Removal System, Axial Fans, Auto-Washing System, Wastewater Recycling System, and a Control System.

Clean Tunnel Air International AS, founded in 1989 in Trondheim, Norway. For over 30 years CTA has been a world leader in the development and provision of air purification for road tunnels. CTA has finished more than 20 air purification stations in more than 10 tunnels. CTA’s mission is to develop, manufacture, and market comprehensive systems to control air pollution in road tunnels.

We take immense pride in delivering this groundbreaking project, made possible by the dedication of over 1,000 workers and more than 100 engineers who brought this vision to life. This achievement underscores the significance of our profession as we strive to make a positive impact on the communities we serve. As we continue with the overhead ventilation, cross passages, road, and profile barriers, we are excited about the future of transportation in Hong Kong.

Get ready – the CKR Central Tunnel is on the horizon, set to make a remarkable impact!

The Road to A Cleaner Environment!