In May's Firehouse, the thermal imaging training article looks at some of the challenges of a search. The reality is that a thermal imager (TI) is a tool; it can make our lives a lot easier when used properly. But we also have to know the limits of the tool so we don't waste time waiting for it to do something it cannot. Online this month, we'll examine a few more images and how they demonstrate a TI's limitations.
Saturation
In Firehouse, the article discusses a term called saturation. A detector becomes saturated when it cannot calculate any higher temperatures than what it is already receiving. As the print article mentioned, many TIs cannot differentiate anything inside the saturation area. This explains why a victim on a burning couch (or bed or chair) can be invisible to the TI. Examine these images and you will see how saturation areas become just white (or red) areas without texture or background. Keep in mind, some higher-end TIs will show detail within a fire area. However, even these TIs have a saturation point that will eventually cause them to loose detail within a fire.
Obstruction
The challenge of beds is, in short, that the heat from the victims is being obstructed. The obstruction problem can extend beyond beds as well, and include other furniture and partial collapses. Keep in mind, that if the object is dense, it will likely block all of the heat from your victim's body. Examine the images below.
Conclusion
Remember, using a TI is not just a simple "point and look" proposition. You have to understand what it is trying to show you, as well as interpret the image that it creates. Practice with the TI as much as possible. This will help keep the limitations and challenges of TI usage fresh in your mind; it will also improve your image interpretation skills.
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 [email protected].
