Scientists, researchers, automation specialists, electrical and building professionals, and security specialists use thermal imaging cameras (TICs) to discover hidden heat patterns and gain new insights in their fields of expertise. Thermal imaging technology, however, can also save lives. Firefighters use thermal imaging cameras every day to see through smoke, locate and rescue victims, identify hot spots, navigate safely, and stay better oriented during response missions.

Figure 2. A firefighter uses FLIR’s K2 to navigate safely and stay better oriented during response missions.

A thermal imaging camera records the intensity of radiation in the invisible infrared part of the electromagnetic spectrum and converts it to a visible image. For a thermal imaging camera, every pixel in a radiometric image is a temperature measurement. Because temperature values can be read from the image, the thermal imaging camera is an ideal tool for firefighting applications.

Small and Compact TICs

Figure 1. The FLIR One allows users to take thermal images with their smartphone or mobile device.

In tandem with the price drop of thermal imaging cameras, another important trend is notable in the thermal camera market: miniaturization. Recent advances in miniaturizing thermal imaging technology have led to the production of very small camera cores, including thermal imagers designed for smartphones (see Figure 1).

In the firefighting market, the trend of smaller thermal cameras means that TICs can now be built with increasingly lower weight – an absolute must for firefighters. TICs need to be easy to handle, and they should not add any more weight to the heavy firefighting attire and equipment, including the suit, air tank, and high-pressure equipment. The K2, FLIR’s addition to its firefighting cameras, for example, can be easily attached to self-contained breathing apparatus (SCBA) gear (see Figure 2).

Firefighting Applications

Figure 3. Heat Detection mode (shown) finds and highlights hot spots. The hottest 20% of the scene is colored in red.

Thermal imaging cameras have several applications. Firefighters use the cameras to protect the lives of victims or team members and to stay safe themselves. Seeing through Smoke Smoke contains a large component of micron-sized carbon soot particles, which visible light absorbs easily. When the particle size is significantly smaller than the wavelength of light used by a sensor, however, the scattering is greatly reduced, making it possible to see through the smoke. Thermal cameras give firefighters better situational awareness, both of where they are in the building and where they are in relation to their team members. The cameras can also be used to find people trapped in the fire.

Fire Attack

Thermal cameras are also vital tools when helping firefighters attack the fire. Obviously, the fire itself is easy to see in a thermal imager, but the relatively cold water being sprayed from the hoses also appears clearly on a thermal image. Firefighters, therefore, can make sure that they get water on the fire as effectively and efficiently as possible.

Figure 4. A thermal image without FLIR’s Flexible Scene Enhancement, or FSX, (left), and a thermal image with Flexible Scene Enhancement (right).
Measuring Temperatures

Thermal cameras measure temperature from a distance, helping protect firefighters against a dangerous phenomenon called rollover – the stage of a fire in which unburned, superheated gases gathered at the ceiling in an enclosed area ignite. By monitoring the temperature of the ceiling with the thermal camera while trying to cool down the smoke, responders will know when a rollover may be imminent and react appropriately.

Search and Rescue (SAR)
FLIR’s K-Series cameras have five color modes that are optimized for various firefighting situations. TI Basic mode (shown) is used for initial fire attack and live-saving operations.

Firefighters do more than fight fires – often they are called on to find missing or injured people. A thermal camera’s ability to see in the dark makes the device an invaluable tool in SAR missions.


Thermal imaging cameras clearly show hot spots where “underground fires” are still burning. Although not visible to the human eye, these fires rage underground. The conditions can lead to a fully outbursting fire, several meters away from its last origin. By further extinguishing and cooling down the area, firefighters can prevent spontaneous self-combustion.

The camera’s Fire mode (shown) is used in conditions with higher background temperatures, like structure fires, where there is already open flames.

Overhaul is a late stage in the fire-suppression process during which the burned area is carefully examined for remaining sources of heat. Throughout the overhaul process, the burned area is carefully examined for hot spots that can cause the fire to reignite. These “hot spots” will clearly show up on a thermal image so that they can be further cooled down or extinguished (see Figure 3).

Thermal Imaging Innovations

Thermal imaging camera manufacturers are continuously looking for ways to improve on compactness, ruggedness, and ease of use. Image quality, however, is also a very important aspect, and in some cases, critical for saving lives.

Thermal imaging cameras use the heat emitted from the environment to see through smoke, locate subjects, or visualize hot spots. In cases where the scene temperatures have low contrast, it can still be difficult and time-consuming to achieve a high-quality picture of the situation.

Search & Rescue mode (shown) is used in conditions with lower temperatures, like outdoor search and rescue operations.

Firefighters need to detect targets quickly, without making manual adjustments to the gain and level. Some advanced non-linear image processing techniques can preserve detail in high dynamic range imagery by extracting image details like edges and corners, and combining them with the original image (see Figure 4).

A TIC in Every Fire Truck

With the recent price drops and ongoing miniaturization, firefighters have less and less reasons to put thermal technology aside. Undoubtedly, in the future, thermal imaging cameras will become even more compact, image quality will further improve, and more features will be implemented in the thermal cameras. Such advancements will hopefully lead to a time when a thermal imaging camera is included in every fire truck.

This article was written by Kristof Maddelein, Editor/Content Manager at FLIR Systems (Wilsonville, OR). For more information, Click Here .

Imaging Technology Magazine

This article first appeared in the December, 2015 issue of Imaging Technology Magazine.

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