Here it is: the emergency that you feared, the one that you dreaded, the one whose potential helped you justify funding your thermal imagers (TIs)."Engines 2, 7, 3, Ladder 2, Quint 11, Ambulance 16 and District 1: Respond to a residential fire, with children trapped at 4567 Eighth Street. That's Engines 2, 7, 3, Ladder 2?."
Here it is: the emergency that you feared, the one that you dreaded, the one whose potential helped you justify funding your thermal imagers (TIs). You know you are properly equipped: you have NFPA-compliant turnout gear and helmet, a new SCBA, recently tested search lines and hose lines, and your new TI. You have it all. The question remains: are you ready to use it all?
Are you comfortable and competent?
Your TI will make your search efforts easier, but that does not mean they will be easy. To have the highest probability of success, you need to be comfortable and competent with your TI. As you know, there is not an indicator on the TI screen that circles your victim and flashes the word "HUMAN"; the TI is designed only to detect relative differences in surface temperatures. This means a TI cannot tell you what you are viewing, only that you are viewing items of relatively different (or similar) temperatures. Determining what you are viewing is the challenge that requires practice.
Shape and heat anomalies
Sometimes, it is not difficult to interpret an image on a thermal imager. Most objects and situations are not complicated or camouflaged. For example, take your TI into the day room at the station and have a partner sit on the couch. It should be relatively easy to determine the image of a person sitting on a couch; the forms of the head, torso, and legs should be clear. However, structure fires are complicated, and potential victims are often camouflaged. In search and rescue operations, the most difficult variable in a search may well be the nature of humans. As you well know, children try to hide under beds and in closets, while adults try to escape. As a result, search efforts can be frustrated because the victim probably will not present his full, recognizable figure (as your partner did on the couch).
Keep in mind that children may cover themselves in an effort to hide. As a result, you will not get a full image of the body. You will instead have to look for "heat anomalies," which are heat signatures that are out of place, or unexpected, in their environment. Imagine a heat signature under a bed. This is unexpected, and therefore an anomaly. It may not obviously be a child, but the heat signature's location should cause you to investigate further. One member of the search team should enter the room, perform a sweep under the bed to determine if this is a victim, and then begin the rescue.
Adults may not hide from fire like children, but they still can present challenges to the search team. Adults (or children) may not even get out of bed before succumbing to the toxic effects of smoke. Normally, we might expect a heat signature on the bed, but the thermal image may not present as an obvious person. Most people sleep under sheets and blankets to stay warm at night. Every layer that keeps cool air off the person's skin also keeps the person's body heat from your TI; thicker layers mean less heat anomaly for your TI to pick up.
It is reasonable to expect that the person still in bed may appear as a lump that displays as a slightly different shade (depending on overall room temperatures). While a lump may be just a mound of covers that were tossed aside in a rush to evacuate, it also could be a person who did not get the chance to evacuate. Because beds can pose such difficulties as hidden heat signatures, fire departments should consider a standard policy requiring that all beds be physically searched (on top and underneath) to ensure that victims are not missed.
Victims do not always display as white
Notice that so far we have been talking about shape and heat anomalies. We have not been discussing the exact shade of gray. Why? Quite simply, because when it comes to rescue, shape is everything. Firefighters need to train to recognize shapes in grayscale. The shade is not as important as the shape. It is the relative shade, along with the shape, that will help you identify victims. Keep this as a key point in your training.
Most fire departments do not have regular access to live fire buildings. As a result, most search drills involve looking for real people in stable environments. Since people are 90-95? F, and most rooms in which they might practice are 60-80? F, drill victims are usually shown as white on the screen of the TI. Make sure you are training to notice the shape, and not the "white" of the victim. In a real fire, the victim is not going to be the hottest object in the picture, so he will be gray or black on the screen. Remember to look for heat anomalies; that is, areas of warmth or coolness that are in an obvious place (on a bed) or in an unusual place (under a bed).
If the rapid intervention team uses TIs, it is critical they understand the issue of shape vs. shade. If the RIT is searching only for a white object to indicate a firefighter, the team may miss the member in need. In addition, RIT members should expect to view only portions of a firefighter in trouble. The member being rescued may have been pinned in a collapse, or may have taken refuge from high heat. The RIT needs to search for the anomalies that might indicate a firefighter.
Tips for search and rescue training
To ensure that you and your firefighters are making your search and rescue TI training as helpful as possible, consider the following:
- Because realistic training is often the best, use the TI in high-heat environments whenever possible.
- In high-heat environments, follow NFPA 1403 recommendations and use rescue dummies as victims.
- To reinforce that firefighters are looking for anomalies and shapes, alternate your victims in low-heat environments: use live victims, heavily clothed live victims, and rescue dummies.
- To emphasize the search for shapes and anomalies, as well as challenge your teams, have victims hide in bathtubs, under beds, behind chairs, etc.
- For realism, as well as to emphasize the search for shapes and anomalies, have firefighter victims in RIT drills partially covered by simulated debris.
- Be proactive rather than reactive: develop your departmental SOG/SOPs for TIs and searches before you need them.
In conclusion, remember that the TI is a great tool for searches. Your goal in searching with the TI is to look for shapes and heat anomalies. Heat anomalies or unusual shapes must be investigated properly. Remember that even though most of your training will show victims as white on the screen of the TI, chances are that in real life they will be gray. TIs do not change victim behavior: prepare for searches in closets, under beds, and behind furniture. Most importantly, though, you need to stay safe and remember the basics!
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 firstname.lastname@example.org.