Sadly, over the decades, there have been some devastating fires in tunnels, resulting in the loss of many lives, as well as life-changing injuries for the survivors. Tunnel fires, even if everyone gets out in time, are also responsible for severe disruption to the traffic flow and wider infrastructure, leading to economic losses. This is why prompt and effective detection and control of fires is essential and when it comes to a tunnel environment, specialist equipment like thermal and flame imaging cameras are used.
How are thermal cameras better than CCTV?
Of course CCTV has an important place in our rail and road tunnels, but thermal and flame cameras have several advantages over them when it comes to rapid responses to incidents. This technology allows firefighters and camera operatives to see through smoke and also to see hotspots that are hidden behind doors and walls.
As thermal imaging doesn’t use visible light – it uses temperature as its source of information – it works better than visual cameras and the human eye. These cameras can also tell operatives what the temperature of an object is – is that pile of fabric just that? Or is it a collapsed pedestrian?
It sees through smoke
Probably the biggest advantage of this tech is that it can see through thick smoke to pick out cars, no-go areas and human bodies. This means rescue teams can target survivors efficiently and quickly, which is vital for a good result. A flame imaging camera can pick up smaller fires despite smoke and other particles in the air, allowing them to be extinguished before they spread and join the larger conflagrations.
It’s not affected by other forms of light
Thermal cameras look for heat signatures, so they’re not blinded by headlights, glare from the sun or visible fires. This means that people, vehicles and animals are visible in difficult conditions. Car headlights are a common form of light interference – and also an interference that we can’t get rid of – so being able to “see past” them is a huge advantage. The entry and exit points of tunnels are often a problem area, because there may be bright sunlight or heavy rain or snow obscuring the CCTV camera’s vision. By using heat rather than light, thermal cameras are simply immune to this problem.
It’s not just about fire
Tunnel controllers can pick up the heat signatures from cars going the wrong way, pedestrians, animals and even objects that fall from vehicles. All these things present a serious hazard in a tunnel so the sooner they’re dealt with, the better, as drivers braking suddenly to avoid an illegal walker are a serious source of accidents.
Many tunnels have blackspots where CCTV cameras can’t see due to shadowing, so CCTV operatives can often miss walkers, fallen objects and animals – thermal imaging fills in these gaps, allowing the tunnel staff to deal with them before they come to light, which can sometimes be too late.