Thermal Imaging | Carl Nix
Writing this column has been a privilege. Each month, I get to share my knowledge and love of firefighting training with you to help keep you safe. Many of you have reached out to me during the past couple of years to share your experiences fighting fires using thermal imaging technology. Thank you for sharing.
With my increasing responsibilities in the fire service, this will be my last column. My thanks to Fire Apparatus & Emergency Equipment and all the folks at the magazine for letting me share my thermal imaging camera (TIC) training insights with you. My final column is a compilation of thermal imaging camera safety tips that I have shared over the years. Stay safe and train every day, and always look out for one another.
THREE-PASS SCAN TECHNIQUE
Using your TIC to scan a room when entering a smoke-filled structure is critical to staying safe. Once you enter the structure, scan the room with your TIC using a three-pass technique. The first pass is across the ceiling looking for heat accumulation, potential vent points, and structural integrity. The second pass is across the middle of the room looking at the physical layout and its contents as well as the location of any secondary egress points. The third pass is across the floor looking for collapsed victims and any special hazards. All three scans take less than 10 seconds but are important to maintaining proper orientation with your TIC.
In a flashover situation, fire conditions progress rapidly from what was a hot fire to what becomes an inescapable fire. As an instructor, I have heard firefighters say that a TIC can help you during a flashover. This is not true. A TIC is a tool to help detect a flashover, but it can’t help you if you’re caught in a flashover. You have to move quickly. You don’t have time to look at your TIC. A preflashover situation is where your TIC can help. Your TIC can give you a visual indication of warning signs that you would otherwise not see. Without the use of a TIC, the thick smoke acts as a visual barrier to what is actually going on above you. Convective velocity, thermal layering, and even rollovers are often hidden inside the smoke and are difficult or impossible to detect. The TIC can help you visualize these events. Your TIC can help you identify how rapidly the fire gases are moving across the ceiling, indicating that they actually have some place to go rather than being confined to the room you are in. Thermal layering is also visible to the TIC. When one or both of these two visuals change, convective velocity slows, or thermal layers descend, it can serve as an early indicator of potential flashover conditions.
Fire suppression is the job most often associated with firefighters. Suppression, control, and safety restoration at the scene are our goals. When lives and property are at risk, we are the first to mount an attack. A TIC is an extremely useful tool during this attack. It can show thermal layers, a safe path for advancement, alternative exits, and the location of the heaviest fire. Using a TIC can help you suppress a fire quickly, efficiently, and safely. Fire departments must have a plan in place to deploy the TIC during fire attack. A TIC should be on the first unit to arrive on the scene. If your TIC is arriving on the third or fourth unit, it may be too late to help in the fire attack. It’s also critical that the TIC be assigned to a firefighter to ensure it comes off the apparatus.
Overhaul is necessary and critical to successfully fighting a structural fire and staying safe while doing so. Using a TIC during overhaul can help determine how far a fire has traveled. Without the use of the TIC, hotspots can easily be missed, resulting in the fire reigniting. There are several advantages to using a TIC for overhaul, but a critical one is the TIC’s ability to detect the smallest temperature differences that can indicate a smoldering fire that has not been extinguished. By identifying a fire that could rekindle, firefighters can help prevent additional property loss and spend less of their time at the scene, which reduces the chance of injury and gets the crew back in service quicker. When overhaul is performed properly using a TIC, it ensures that the fire is completely out and there is no threat of reignition.
SEARCH AND RESCUE
How many times has your local police department called you for help with locating a missing person? Maybe it’s an elderly woman who has wandered away from her home or a child who has gotten lost in the woods. With the aid of a TIC, firefighters can pick up hot spots that can help guide them to a location where a person may be. Using a TIC often cuts minutes off a search that can mean the difference between saving a life and losing a life.
MOTOR VEHICLE ACCIDENTS
Motor vehicle accidents happen every day on our roadways, but how often do firefighters use the TIC when responding to one? When arriving on the scene of a motor vehicle accident, it’s critical to determine how many people were in the vehicle prior to the accident to account for all injured or noninjured parties. Your TIC can be used to check the automobile seats for hot spots to determine how many people were in the car. A TIC cannot see through glass, so be sure to open or remove the door or window of the vehicle before you scan. Don’t scan just one seat but multiple seats at the same time for comparative purposes since your TIC will show residual heat. What you’re looking for is contrasting heat signatures.
Even if your department is not a trained hazmat team, I’m sure you have responded to one or more calls that have involved hazardous materials such as an overturned vehicle or tanker truck, a chemical emergency, or a meth lab fire. Using a TIC for any hazmat call lets firefighters see what the naked eye cannot see. Tracing a spill on the roadway in a rain storm is an environmental necessity. Seeing the gases of a container at a safe distance is critical to the safe outcome of a hazmat mission. Having the ability to see the content level of an enclosed container at a safe distance is critical to the safety of the firefighting crew.
IDENTIFYING HEAT PATTERNS
Most firefighters can identify heat patterns when looking at a large structural fire, but what about the smaller, more subtle heat signatures? Firefighters need to be trained to find the less-than-obvious heat signatures. Place a space heater on the other side of a closed door at your fire station. Give the door several minutes to warm up. Have your firefighters conduct a search and see if they recognize the heat pattern prior to opening the door. Whether they notice it or not, you can use this opportunity to talk about the benefit of recognizing smaller heat sources. If you have both solid core and hollow core doors in your station, you can set up several space heaters to show the difference between these different door construction types.
CARL NIX is a 32-year veteran of the fire service and a retired battalion chief of the Grapevine (TX) Fire Department. He serves as an adjunct instructor for North Central Texas College and a thermal imaging instructor for Bullard. Nix has a bachelor of science degree in fire administration and is a guest instructor for Texas A&M Engineering Extension Service’s (TEEX) annual fire training in Texas.