The "Five Deadly Sins" Of Thermal Imaging

This column is the final installment of a two-part series on the “Five Deadly Sins” of thermal imaging. Last month, we concentrated on the two most common and potentially most dangerous sins: standing and walking in unsafe environments and abandoning traditional safe-search techniques.

As a thermal imager restores sight to an otherwise blind firefighter, the temptation to abandon basic skills in the pursuit of more expedient operations is great; however, Murphy’s Law is real and Murphy has a way of kicking firefighters at the most inopportune times. Batteries die, imagers get dropped and sometimes they fail – if any of these were to happen, you need to know how to get out. You simply cannot replace basic firefighting skills with a thermal imager. You can merely augment them.

This month’s column focuses on the last three sins, which, as a whole, are less problematic than the first two, but still pose risks to the firefighter who is unaware of the potential pitfalls. Though these are considered “lesser sins” in terms of the dangers they pose, they can still lead firefighters into bad situations.


Deadly Sin 3 – Advancing at an inappropriate speed. When most people think about inappropriate speed, they think “too fast”; however, a thermal imager can lead a firefighter to operate too slowly as well. Deadly Sins 1 and 2 are common to moving too quickly; however, when a firefighter becomes engrossed in interpreting every shape and object on the imager display, his or her advancement can be slowed dramatically as well. Neither is desirable.

While less common, moving too slowly poses hazards to the firefighter. The firefighter spends longer in the hostile environment, using more of the limited air source to perform less work. Additionally, while moving more slowly through the structure, the fire continues to burn, increasing the risks of partial collapse or structural failure during the course of his slower search. Of course, any victims in the building can ill afford delays in being removed from the environment.

Moving too quickly in a building leads a firefighter deeper into the structure. As a result, you may unintentionally stretch your air supply beyond a safe reserve, placing yourself at risk of running out of air inside. Also, a firefighter with a thermal imager has a tendency to move faster than other firefighters on the same crew since he or she can see while the others cannot. Regardless of how many imagers are deployed at an incident, the basic safety rule of staying with your partner does not change.

• Training For Safety

Firefighter knowledge and regular practice are the most effective ways to avoid all of these “Deadly Sins.” To avoid moving too slowly, firefighters must remain focused on their task. If they are performing a primary search, for example, firefighters are essentially looking for fire, victims and a safe path of advancement, including means of secondary egress. Identifying whether a tabletop is covered with books or boxes is immaterial; similarly, a firefighter inside a burning structure does not benefit from knowing the types of light fixtures on the ceiling. Establishing appropriate speed will come from training and practice.


Deadly Sin 4 – Misinterpreting images. Misinterpreting what an imager is displaying can cause firefighters to make poor decisions. For example, a firefighter could interpret a white area on a wall as indicating a hidden fire, when it may only be indicating the location of a heating duct. Or, a firefighter may not immediately recognize a reflected image and therefore may search or advance in the wrong direction.

Common and ordinary things can look very different when viewed with a thermal imager. A puddle of water on the floor from a hoseline can look identical to a hole in the floor to a thermal imager. Items that are normally warmer (whiter) than the environment in non-fire training (people/victims) can appear cooler (blacker) than the environment during a fire. Image interpretation is an acquired skill and it takes quite a bit of practice in order to become second nature.

• Training For Safety

Proper image interpretation is developed over time through regular usage of a thermal imager. Only with frequent use will firefighters become comfortable with understanding how it develops images and, more importantly, what those images portray. Firefighters should be using an imager on a weekly, if not daily, basis and developing their image-interpretation skills at training burns, as well as by looking around the firehouse. Even building inspections can turn into opportunities to practice using a thermal imager and understanding its imagery. If you don’t understand what you see, investigate until it becomes clear. This will help you make sense of unusual images when in the heat of the battle.


Deadly Sin 5 – Misapplying the technology. Generally speaking, this will generate more frustration than danger. Firefighters must know the limits of thermal imaging technology as well as the scope of its capabilities. For example, firefighters cannot expect a thermal imager to assist them in recovering a drowning victim, as imagers will not see through water. You cannot use the thermal imager to accurately and reliably tell you the temperature of any surface particularly shiny or reflective surfaces like glass.

While misapplication of the technology may not necessarily place a firefighter at greater risk, a lack of understanding of limitations and capabilities can either falsely lower or falsely raise a firefighter’s confidence in the thermal imager as a valuable tool.

• Training For Safety

Ensuring proper application of the tool is a matter of solid training and frequent reminders. Firefighters should receive a formal training program on how to use thermal imagers, how they function and what limitations they have. Some fire departments have developed their own imager training programs, as have some state-run fire training facilities. Fire departments can also turn to private training companies, or even the manufacturer of their thermal imagers, for formalized training.


A common theme to avoiding all five “Deadly Sins” is one word – training. This two-part series identified five common challenges to safe thermal imager usage. Firefighters must first recognize the challenges, then incorporate training programs that meet these challenges head-on. Thermal imager use must be incorporated into all aspects of fire training and should not be considered as a stand-alone topic. If firefighters practice the pulling and advancing of the hose while carrying a thermal imager, they will become better at using it to make their advancement easier. This philosophy must extend to all facets of emergency operations. With proper and safe training, firefighters will be better equipped to use their tools in an appropriate manner.