Thermal Imaging: The Power of Investigative Application Modes

In the United States, firefighters responded to 1.3 million fire calls in 2021. In that same year, they responded to 2.9 million false alarms. These calls included incidents such as: odor of electrical, caller states they smell something burning in their home, and occupant states there is a light haze of smoke in the building but no visible fire. The amount of time spent investigating many of these incidents can be reduced by training and equipping firefighters with thermal imaging cameras with an investigative mode application feature.

What is an investigative mode application feature?

Many fire service TICs have offered these valuable features in the past, but many firefighters lacked proper training on these features. These were scene in the following makes and models:

  • Bullard Electronic Thermal Throttle
  • FLIR KXX Search & Rescue Mode
  • Drager Thermal Scan
  • Argus Size-Up Mode and Hot Spot/Cold Spot Tracker
  • Seek Thermal Survey Mode
  • Scott X380 Hot Spot/Cold Spot Tracker

Please see the following video examples/explanations for a few of these models:

Bullard Electronic Thermal Throttle:

FLIR Search & Rescue:

Seek Thermal Survey Mode:

These application modes are all intended to be used in lower temperature environments (typically less than 300 degrees Fahrenheit or 150 degrees Celsius). They allow for early colorization of thermal threats that may not be optically visible. Some manufacturers have these investigative modes preset for early colorization beginning as low as 150 degrees Fahrenheit/ 65 degrees Celsius. Some models allow for the end user to adjust the parameters of the temperature range to highlight areas of interest. This is known as an isotherm. Where the overall background temperatures are in gray scale, but the area of interest is highlighted in one specific color such as blue in Bullard’s Electronic Thermal Throttle or yellow in Drager’s Thermal Scan feature.

Important-Before Using an Investigative Application Color Palette:

It cannot be overemphasized that whatever make/model of thermal imaging camera is in use, that the firefighter does not use the spot temperature for quantitative measurements. In other words, the direct temperature measurement number located in the bottom right corner of the viewfinder/display is not accurate.

Variables such as emissivity, distance to target, atmospheric attenuation, angle of incidence, moisture on the lens, and wind speed cannot be accounted for in fire service TICs. They are not industrial thermal imaging cameras and are not designed to capture exact measurements. However, they are intended to provide diagnostic information from a qualitative perspective to assist them in decision making.

If you would like to learn more about this subject, please see our article “The Danger of The Spot Temperature.” This explains this in depth and explains why NFPA 1801-2021 removed the spot temperature from the start up application mode (TI-BASIC):

The Danger of the Spot Temperature – Insight Training LLC


Firefighters often operate either in a quick response mode such as fire attack or rescue or an investigative mode where they are looking for objects or persons in less emergent situations. If their thermal imaging camera is equipped with an investigative mode color palette, it may provide the following:

  • Early colorization of thermal threats can be used to quickly identify areas of interest in either operational context to maximize efficiency.
  • From size-up, to locating the fire, to thermal situational awareness, to locating overheated areas or components, this low temperature application-based mode has tremendous value.


In the past, manufacturers have instructed firefighters NOT to use these investigative application modes during fire suppression efforts. However, firefighters continue to operate in the most challenging environments to date. And in many cases, the location of the fire is not immediately known. Even with the aid of thermal imaging cameras, Firefighters often enter the structure remote from the fire’s location and have difficulty locating the fire. Why is this the case?

  • Training: Many firefighters lack proper training on their device and do not understand high/low sensitivity and when their device engages colorization.
  • Gray Scale: Firefighters do not interpret gray scale heat signatures well under stress. They are moving quickly, and their scans are often too fast. These are not quantitative analysis scans being done by trained thermographers. An investigative mode that colorizes superheated areas earlier can aid firefighters in locating hidden fire, superheated areas that are often missed, and can provide them with information to enhance their suppression efforts by directing them to the source of the problem.

As shown in the following video, we can see how much easier it is for the firefighters to identify the colorized areas that are at 200 degrees Fahrenheit (apparent temperatures).

In summary, a fire service TIC that is equipped with an investigative application mode can be a true force multiplier for firefighters. It can provide vital information during:

  • Size-Up
  • Entry
  • Fire Attack
  • Search
  • Overhaul
  • False Alarms and Investigative Calls.
  • Other use: Downed power lines, lost person searches, and more.

Two important areas of consideration:

Color blindness: It is important to note that many individuals are color blind. Fire departments should test their firefighters and assist those who have trouble identifying certain colors. A simple small scale live fire test can help the individual with color blindness to develop their own color palette based on their abilities. It is not a limitation if fire departments will properly address this so they can use these devices to their benefit.

Too much colorization: In the event, the device is showing large amounts of colorization, this can overwhelm the end user and they will not notice the convection currents that are striking them. If a firefighter is using an investigative mode color palette/application in a newer model thermal imaging camera and they encounter heat conditions beyond those applications dynamic range, they can simply tap the green button and the device will go back to TI-Basic which is the NFPA 1801 approved color palette for firefighting in high heat environments.

We hope this information is useful and that you share this with your respective organizations for training purposes.

Andy Starnes

Owner/Founder Insight Training LLC

Level II Thermologist