Myths vs. Reality in Thermal Imaging - Part III

In January and March 2003, we examined the first eight myths of thermal imaging. This month, we wrap up this series with two final common myths, including one suggested by a reader. As mentioned before, if your thermal imagers (TIs) are not performing as you thought they would, or if they do things that do not make sense to you, please contact me at jonathan_bastian@bullard.com. We can address the issue here, as there may be other readers experiencing similar issues who can learn from your experiences.

Myth #9-TIs Make Firefighters Safe

This is probably the most common, and potentially most dangerous, misconception about thermal imaging in the fire service. First, let me be clear: TIs do help make firefighters safer! The challenge is that TIs cannot -in and of themselves- make firefighters safe.

Historically, firefighters have crawled through involved structures due to three main factors. First, before SCBAs became standard equipment, firefighters had to breathe whatever air was available in the building. Because the cleanest, coolest air was closer to the floor, firefighters took steps to place themselves near the cleaner air. Second, firefighters crawled because their protective gear demanded it. Rubber coats, metal helmets and ? length boots allowed the heat near the ceiling to abuse firefighters who failed to stay low. Last but not least, because the cleaner air near the floor was less smoky, firefighters were able to see better when they crawled near the floor.

Times are different now. Mandatory SCBA use ensures that firefighters can breathe regardless of where the cleanest, coolest air is. Modern materials, NFPA standards and almost-universal use of bunker gear means that firefighters can be exposed to greater heat levels, without even recognizing the brutal environment around them. Finally, with a TI, a firefighter can now "see" through the smoke. In short, technology has removed most of the obstacles that make a firefighter want to stay low in a structure fire.

Technology has not removed the risks inherent in firefighting, however. Technology hasn't eliminated the risk of flashover and it doesn't prevent the regular occurrence of rollover down the hallway. Technology has not strengthened stairwell or floor construction under fire conditions (one could argue technology has actually made them worse). The reality is that even though a firefighter can breathe, feel little heat and see throughout a building, a structure fire is still a very hostile environment. The TI removes the firefighter's last major obstacle: lack of sight.

To avoid fooling themselves into thinking they are "safe," firefighters must train regularly, practicing basic firefighting skills in conjunction with TI use. "Sight" regained through the use of a TI should help improve search speed and accuracy, but it should not replace standard search practices. Fire companies still need to bring a hoseline or search rope with them, despite the fact that they have a TI in hand. Companies still must negotiate their way through a building by using a traditional left- or right-hand search, maintaining constant contact with an exterior wall as well as a mental map of the structure. All the while, they need to do this the old-fashioned way: by crawling.

Maintaining basic skills is critical for two reasons. First, it reinforces to the firefighter that he is in a hostile environment and needs to exercise due care and caution. Second, this ensures that firefighters have a way out of the building should the TI be lost for any reason. For the most part, a person who uses his eyesight to get into a building is reliant on his eyesight to get out. Turning back on a search line and reversing a left-hand search are guaranteed ways to lead a team out of a building. Firefighters and their officers owe themselves a guaranteed way out.

Practical Application: To reinforce the importance of maintaining basic skills, practice a room or building search with a TI (this can be done in live fire conditions, in a simulated smoke environment, or in a darkened room). At some point during the drill, have the instructors take the TI from the participants and ask them to continue the search with traditional techniques, and then find their way out of the structure. Participants will quickly see how important it is that they do not rely on sight alone to guide their work. To help ensure the proper use of these valuable tools, when placing TIs into service, it is critical that fire departments promptly update policies or guidelines to include proper equipment use.

Myth #10-The TI Will Identify Everything in the Structure

Burt from Wisconsin contacted me about this following issue. He noted the challenge that stairwells can present to firefighters who are using a TI. Remember that a TI displays relative differences in surface temperature. A scene that includes objects that vary in temperature will be easier to interpret than a bland scene, where all of the objects have nearly identical temperatures.

A stairwell, especially one that is open or vaulted, can be "invisible" to the TI under two primary conditions. First, imagine investigating an abandoned building in conditions of darkness or low light. The clever firefighter will use his TI to help him navigate the building as well as search for occupants. However, a vacant building generally will present a bland scene, because without utilities, all of the structural contents will equalize to the ambient temperature. Because the stairs, floors and walls are all the same temperature, there will be little for the TI to display. Differences in materials, and therefore their emissivities, may help create some differentiation in the scene, but it may still be difficult to see the stairs.

The second factor that may interfere with a firefighter's ability to see a stairwell is the presence of extensive heat build-up above the stairs, such as at a two-story residence with an open foyer. In this situation, a TI-equipped company coming down from the second floor could scan the area and have its TI show the extreme heat near the ceiling. Because the temperature range could be quite wide, the TI may show the floor, stairs and railings as essentially the same temperature. Therefore, the TI will display them as the same or similar shades of gray.

Practical Application: As mentioned in Myth 9, firefighters need to remember the basics of firefighting: stay low and proceed cautiously. Also, realize that holes in abandoned buildings or furniture in unused buildings (such as a bank on Sunday) may be equally difficult to discover with the TI. To protect themselves, firefighters should practice reading thermal images in bland scenes, looking for other clues to the presence of stairwells, doorways, furniture and other structure items.

Conclusion

While TIs have repeatedly proven themselves to be invaluable, life-saving tools for the fire service, they are like any other tool in that they need to be used properly. Just as a misused ventilation saw can cause serious injury, so can a misused TI. To ensure that the TI is adding to their safety rather than compromising it, firefighters must remember the basics of firefighting and remember how objects and dangers can be "hidden" from the TI.

Use your TI often, wisely and safely.

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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 jonathan_bastian@bullard.com.

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