Worldwide Support
Over 25 distributors and support centres worldwide

Flexible maintenance contracts
Tailor made plant specific contracts with 24Hr Support

30 years experience
Developing, manufacturing and installing

Case Study - TunnelTech 900 Series Implementation in Świnoujście North West Poland

The Świnoujście Tunnel, connecting the Wolin and Uznam islands in the city of Świnoujście, Poland, stands as a remarkable engineering feat. Stretching across 3.4 kilometres, with the tunnel section spanning 1780 meters, this passageway serves as a vital link between the islands.

A substantial part of this tunnel, around 1484 meters, was excavated using a Tunnel Boring Machine (TBM), while the remaining 295 meters employed the cut-and-cover method. The tunnel boasts a 12-meter diameter, facilitating bi-directional traffic. Each traffic lane spans 3.5 meters, complemented by evacuation routes and 1.75-meter wide shoulders. Situated approximately 38 meters below sea level at its deepest point under the Świna river, the tunnel operates as a critical transport artery.


In 2023, the tunnel welcomed a crucial addition to its infrastructure: air quality monitoring systems provided by Codel. Five TT 900 series monitors, configured in two sets, and three TT 801 cross-tunnel flow monitors were installed. These systems, integrated into the tunnel’s ventilation setup, constantly measure air quality parameters like Visibility, CO, NO, NO2, alongside air flow and temperature.

Courtesy of the tunnel’s ventilation operators, we’ve obtained a comprehensive dataset covering a two-week period from September 26th to October 10th, showcasing readings from various locations within the tunnel.


Location EA1_5
Location EA1_5

The measurements in the tunnel reveal a distinct diurnal pattern, with pollutant levels surging during the morning rush hours around 6:00 AM, remaining elevated till approximately 10:00 PM, and then gradually decreasing at night, aligning closer to ambient air levels. Night time traffic within the tunnel is notably minimal. Over the initial two months since its opening, the Annual Average Daily Traffic tallied at 13,000 vehicles, primarily comprising passenger cars traversing the tunnel.

Location EA1_3 Visibility and Flow
Location EA1_7 Visibility and Flow
Location EA2_3 Visibility and Flow

Analysing the flow data from locations EA1_3, EA1_7, and EA2_3 within the tunnel, it’s evident that the bi-directional traffic induces relatively low velocities with significant fluctuations in both directions. Notably, all three sensors showcase a strong correlation among their measurements, affirming their accuracy and the representativeness of these locations within the tunnel. This correlation underscores the reliability of the collected data, aiding in assessing traffic flow dynamics effectively.

The TunnelTech 900 is an all-in-one Visibility and air quality monitor based on backscatter light measurement technology for visibility and electrochemical cell technology for gas measurements.

The TunnelTech 801 monitoring system for continuous evaluation of air flow rate and flow direction in tunnels