Myths vs. Reality in Thermal Imaging - Part III

While TIs have repeatedly proven themselves to be invaluable, life-saving tools for the fire service, they are like any other tool in that they need to be used properly.

Practical Application: To reinforce the importance of maintaining basic skills, practice a room or building search with a TI (this can be done in live fire conditions, in a simulated smoke environment, or in a darkened room). At some point during the drill, have the instructors take the TI from the participants and ask them to continue the search with traditional techniques, and then find their way out of the structure. Participants will quickly see how important it is that they do not rely on sight alone to guide their work. To help ensure the proper use of these valuable tools, when placing TIs into service, it is critical that fire departments promptly update policies or guidelines to include proper equipment use.

Myth #10-The TI Will Identify Everything in the Structure

Burt from Wisconsin contacted me about this following issue. He noted the challenge that stairwells can present to firefighters who are using a TI. Remember that a TI displays relative differences in surface temperature. A scene that includes objects that vary in temperature will be easier to interpret than a bland scene, where all of the objects have nearly identical temperatures.

A stairwell, especially one that is open or vaulted, can be "invisible" to the TI under two primary conditions. First, imagine investigating an abandoned building in conditions of darkness or low light. The clever firefighter will use his TI to help him navigate the building as well as search for occupants. However, a vacant building generally will present a bland scene, because without utilities, all of the structural contents will equalize to the ambient temperature. Because the stairs, floors and walls are all the same temperature, there will be little for the TI to display. Differences in materials, and therefore their emissivities, may help create some differentiation in the scene, but it may still be difficult to see the stairs.

The second factor that may interfere with a firefighter's ability to see a stairwell is the presence of extensive heat build-up above the stairs, such as at a two-story residence with an open foyer. In this situation, a TI-equipped company coming down from the second floor could scan the area and have its TI show the extreme heat near the ceiling. Because the temperature range could be quite wide, the TI may show the floor, stairs and railings as essentially the same temperature. Therefore, the TI will display them as the same or similar shades of gray.

Practical Application: As mentioned in Myth 9, firefighters need to remember the basics of firefighting: stay low and proceed cautiously. Also, realize that holes in abandoned buildings or furniture in unused buildings (such as a bank on Sunday) may be equally difficult to discover with the TI. To protect themselves, firefighters should practice reading thermal images in bland scenes, looking for other clues to the presence of stairwells, doorways, furniture and other structure items.


While TIs have repeatedly proven themselves to be invaluable, life-saving tools for the fire service, they are like any other tool in that they need to be used properly. Just as a misused ventilation saw can cause serious injury, so can a misused TI. To ensure that the TI is adding to their safety rather than compromising it, firefighters must remember the basics of firefighting and remember how objects and dangers can be "hidden" from the TI.

Use your TI often, wisely and safely.


Jonathan Bastian is a Thermal Imaging Specialist for Bullard. He is certified as a thermal imaging instructor by the Law Enforcement Thermographers' Association (LETA). He is also the author of the FD Training Network "FireNotes" book, Thermal Imaging for the Fire Service. Bastian served 12 years on the North Park, IL, Fire Department, including the last three as a captain. He has taught classes on thermal imaging, rapid intervention teams and search and rescue operations. He is currently a police officer in Lexington, Kentucky. If you have questions about thermal imaging, please send them to