News stories about structural fires make great TV coverage for the media. I’m sure you can quickly think of a recent news story that involved a fire of some type. Maybe it was a structural fire, car fire, or chemical fire.

Fires are newsworthy, and we in the fire service know that at any time we might be standing in front of a reporter answering questions about a fire we are battling. Recently, I saw a news story involving a structure fire at a local restaurant. The firefighting crew had left the scene thinking the fire was out, only to be called back when the fire reignited.

I’m sure we can all relate to this scenario, and it serves as a great opportunity to discuss the unseen dangers that hide within structures when the fire appears to be out. Keep in mind that fire is deceptive, which is why it’s so difficult to fight. A smoldering fire doesn’t always give firefighters clues to where the fire is hiding within the structure. The obvious visible signs that many firefighters look for when evaluating concealed fires include blistering paint and smoke emitting from a wall. Crackling sounds from combustion coming from the structure are another clue that a fire is hiding somewhere.

One of the most challenging fire conditions to control is the one we don’t see. The most critical tool in your arsenal during situations like this is your thermal imaging camera (TIC). A TIC helps you locate hidden fires. Firefighters need to be using this tool in every situation where hidden fires may exist. I recommend using your TIC to scan from a distance of at least 10 to 15 feet away, so you have a broad perspective of any hidden heat conditions that may cause a fire to reignite. Begin by using your TIC to scan the structure’s interior wall and ceiling surfaces for signs of abnormal heat. What do I mean by abnormal? To distinguish abnormal from normal, firefighters need to consider what an ordinary heat source could be and how it may be impacting thermal signatures. For instance, a fuse box or appliance on the other side of a wall, active heat ducts inside the wall, or outside sunlight affecting the area and warming it can impact what the TIC image shows.

Firefighters should always look for anomalies in the thermal signature of surfaces that cannot be explained by ordinary heat sources that might be creating such a thermal anomaly. Keep in mind, just because your TIC shows you a hot spot doesn’t always mean there’s a hidden fire. Opening up a wall before further investigation could result in unnecessary damage to the structure. Always investigate thoroughly and rely on your firefighters’ experience and knowledge before drawing any conclusions. Your TIC is there to help guide you and should never replace your firefigh