By Claire Swedberg
Sept. 26, 2011—Sweden's national transport administration,
Trafikverket, is employing
RFID tags to transmit air-quality data to trigger ventilation controls within the 6-kilometer-long (3.7-mile-long)
Norra Länken (Northern Link) tunnel, currently under construction in northern Stockholm. The RFID system, provided by
Identec Solutions, has been in use since tunnel construction commenced in February 2009, and is slated to continue through 2015.
The tunnel consists of five construction areas, managed by five separate road and tunnel construction contracting companies. The technology allows the agency to monitor airflow throughout the tunnel, in order to ensure construction workers' safety, by providing each employee with an RFID badge, and by installing gas sensors that measure the levels of toxic gases around each individual, as well installing RFID
reader to help determine the locations of workers within the tunnel. That data can then be used to automatically adjust the output of six tunnel fans within the tunnel, intended to ventilate the underground area.
Air ventilation for tunnel construction crews typically consists of a non-automated use of fans to ensure that fresh air is flowing into the tunnel, and that any unhealthy air is removed. The air can be contaminated by the fuel-operating equipment and vehicles located within the tunnel.
Identec Solutions has begun offering its automated solution, known as the Automated Ventilation Control System, as part of its Watchertunnel personnel-safety technology portfolio. Trafikverket has been the company's first customer. Watchertunnel, a broad solution for tunnel construction safety management, includes closed-circuit television (CCTV), access control and alarms. The Automated Ventilation Control System provides a new layer of security, the firm reports, by monitoring air quality and providing an automated fan response.
The solution consists of Identec's SensorSmart badges that have battery-powered Identec i-B2 CC tags. The badges are worn by staff members, and the same type of ultrahigh-
frequency (
UHF) tag has been attached to numerous vehicles used within the tunnel. A total of 1,200 to 1,500 i-B2 CC tags have been deployed to date.