Thermal imaging cameras help guarantee fire safety in tunnels

Thermal imaging cameras help guarantee fire safety in tunnels

Monday, June 27, 2016

Tunnel fires can have devastating effects on people and infrastructure. The consequences of fires in tunnels can in the worst cases result in severe fatalities, material damage and disruption of important infrastructure lines. Effective fire prevention, detection and control can therefore save lives and prevent high costs. Tunnel operators and emergency response teams have always relied on intelligent technology to support them in these tasks. Thermal imaging is one of these technologies.

Although traditional CCTV cameras are still an option for tunnel monitoring, thermal imaging cameras have a number of advantages to offer. In tunnels, thermal imaging cameras are used to monitor traffic flows or detect incidents in an early stage. In other applications, like firefighting, thermal imaging cameras are a reliable addition to human vision, because they can help firefighters see through smoke or detect hot spots. Thermal imaging technology makes use of temperature information coming off the environment. It does not need any light to operate and therefore, it has some distinct advantages over visual cameras and even human vision.

  • See through smoke:One of the biggest advantages of thermal imaging cameras in the field of tunnel safety is that they can effectively see through many types of smoke. This makes it the ideal technology for emergency response teams to find their way through a smoke-filled tunnel or for incident detection systems to spot incidents in time.
  • Not affected by sun glare: Glare from the sun blinds conventional video cameras, effectively hiding vehicles, people, and animals. Thermal cameras ignore this glare, and only respond to the heat signatures they detect.
  • Not affected by headlights: Headlights are confusing to CCTV cameras. This causes false and missed calls and makes accurate observation of highway traffic at night impossible. Thermal cameras are immune to headlight glare, so they see clearly.
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Tunnel operators can use thermal imaging cameras to detect stopped vehicles, wrong-way drivers, queues, slow-moving vehicles, fallen object or pedestrians in a matter of seconds.

  •  See through shadows: Video cameras can miss pedestrians, cyclists, animals, and even cars if they’re in the shadows. This is especially the case at the entry or exit of a tunnel, where it can be very dark inside because of shadows and very bright outside because of sunlight. But since thermal cameras see heat, not light, there are no shadows in a thermal world, so this will not affect visualization.
  • Long-range night viewing: At night, a highway looks like an indistinct row of lights to a video camera, making meaningful data collection and incident assessment impossible. But thermal cameras see the heat signatures of vehicles clearly from miles away. They also provide clear video of the roadsides for awareness of parked vehicles or other hazards.

Thermal imaging applications

Automatic Incident Detection (AID)

Traffic incidents in tunnels can result in severe fires. That is why it is extremely important for emergency services to be responsive and avoid further escalation of an incident, for example by avoiding secondary accidents. Effective incident management depends entirely on fast incident detection and verification. Tunnel operators can use thermal imaging cameras to detect stopped vehicles, wrong-way drivers, queues, slow-moving vehicles, fallen object or pedestrians in a matter of seconds, so they can prevent secondary accidents from happening.

Thermal imaging cameras are especially effective when installed at the entry and exit of a tunnel, because that’s where traditional CCTV can experience difficulties in dealing with direct sunlight or precipitation. FLIR’s high-performance thermal imaging cameras give you uninterrupted 24-hour detection of vehicles, pedestrians and cyclist regardless of the amount of light available.


Thermal imaging can help prevent fires or detect them in an early stage so they don’t have a chance to spread.


Thermal Imaging Cameras (TICs) help firefighters see more clearly in the darkest and smokiest environments.


Compared to traditional headlights, thermal vision enhancement systems offer increased vision through smoke, dust or precipitation.

Early fire detection

Fire can cause severe damage to tunnel structures, resulting in high costs. Thermal imaging can help prevent fires, by detecting hot-spots, or detect fires in an early stage so they don’t have a chance to spread. Thermal cameras can be configured to generate a direct alarm output to a control room operator when user-defined maximum temperature thresholds are exceeded. Thermal imaging cameras like the FLIR FC-Series are widely used to monitor continuously for hot spots, so that an early fire alarm can be triggered and fires can be avoided.


When moving into a tunnel fire scene, a thermal imaging camera is an indispensable tool for firefighters to help them quickly visualize their plan of attack, locate hot spots, and save lives. Today’s Thermal Imaging Cameras (TICs) offer easier ways to see more clearly in the darkest, smokiest environments by showing big, bright thermal images that help them maneuver more strategically, stay better oriented, and find victims faster. With greater situational awareness, they can improve safety and the likelihood of successful outcomes.

Driver vision enhancement

FLIR’s thermal imaging night vision systems installed onboard emergency vehicles allow drivers to see clearly in total darkness or in bad weather conditions. Compared to traditional headlights, they offer increased vision through smoke, dust or precipitation, and therefore better situational awareness.



This new fire engine from the Rosenbauer’s AT-Series has a FLIR PathFindIR thermal imaging camera installed in the bumper to help the firefighters see through smoke, which is especially useful in case of tunnel-fires.

Rosenbauer includes FLIR thermal imaging cameras in cutting edge fire engine

Firefighters from over the world have realized the potential of thermal imaging cameras for fire brigades. Whether to see in the dark or through smoke, thermal imaging cameras can be an invaluable tool for firefighters. As the world’s leading fire engine manufacturer Rosenbauer has chosen to include thermal imaging cameras from FLIR in their new line of cutting edge fire trucks.

According to Roland Jungmair (Rosenbauer) the success of the FLIR PathFindIR thermal imaging camera on the Panther ARFF vehicles has also lead to other applications. “When we saw how effective the FLIR PathFindIR thermal imaging camera is as a driver vision enhancement aid and combined that with the fact that it can see through smoke, we immediately realized that it would be an incredibly useful tool for a firefighter that has to cope with a smoke-filled tunnel.”

“A lot of our highways pass through tunnels and car crashes in a tunnel are therefore not unheard of. In some cases such a car crash results in a fire. In a tunnel the smoke cannot escape as easily as above ground. Not only does that mean that it is very important to evacuate a tunnel as quickly as possible to prevent people from developing respiratory problems due to the smoke, it also makes the firefighters’ job difficult due to very low visibility. After conferring with firefighters specialized in tunnels we drew the conclusion that the best way to adapt our trucks for tunnel firefighters to meet the special challenges of tunnel firefighting was by using thermal imaging cameras.”

Automatic incident detection for the Calgary Airport Trail Tunnel, Canada

Video-based automatic incident detection technology from FLIR has been installed in numerous tunnels around the world. In the Calgary Airport Trail Tunnel in Canada, FLIR’s video analytics boards are combined with both visual cameras and FLIR thermal imaging cameras. For both types of cameras, FLIR delivers accurate detection of a wide range of incidents, including pedestrians, fallen objects and inverse direction. The tunnel runs under the airport runway. It is 620 metres, 36 metres wide and has a vehicle clearance of 5.3 metres. The Airport Trail tunnel opened to traffic in May 2014 and connects the airport to other important areas of the city. The tunnel includes 8 FLIR FC-Series ITS cameras, which produce accurate traffic images on which the smallest detail can be seen.