What I love about my job is that I get to share my knowledge about thermal imaging in person wherever I travel and through posts on various social media platforms.
This month, I want to write about an incident that happened while in an underground parking garage. While fire service thermal imagers (TIs) are valuable tools in firefighting, we do have to understand some of the challenges in using them when it comes to underground parking garages.
INCIDENT DETAILS
A good friend, who is a captain on his fire department, reached out to me about a serious issue he experienced with a TI when responding to a motor vehicle fire in a large underground parking garage the size of a city block. Upon entering the structure to try to determine the location of the vehicle, they were met with a wall of thick smoke. He knew that using the TI had an added benefit to guide them to where they had to go, but 13 of the structure’s sprinkler heads automatically activated, causing a loss of vision with the TI, and total naked eye visibility was gone.
Manual search procedures quickly went into effect. Because they were unable to locate a standpipe or a means of egress, air management and accountability quickly became major concerns. Additional firefighting resources were brought in to help control fire extinguishment and aid with additional air management.
1 2 Multiple heat signatures detected from recently driven vehicles and overhead lighting. (Photos courtesy of Bullard.)
WATER PARTICULATE
His question to me was why did they lose visibility with their TI? The water particulate from the sprinkler system was dense enough to cause the infrared energy to be absorbed, preventing it from being detected and interpreted by the TI and rendering it ineffective for the operation. Another detail to mention is that anytime there is steam buildup, remember to wipe condensation off the front lens and display screen because this degrades your imagery.
We understand that a TI detects infrared energy, which is heat that is made visible onto the viewing display screen of your TI. Objects that are hot or warmer will show up as white or brighter and objects that are cold or cooler will show up as black or darker, and everything else in between will be in various shades of gray. The TI requires a temperature variance, and at times you can find yourself looking at a bland viewing screen, depending on how well objects stand out from one another. Related to detector sensitivity and the variance of temperature in objects being viewed is “thermal contrast,” where an object being viewed may be low contrast, and others may be high contrast.
Working in underground environments can have its challenges when you add some dense smoky conditions into the equation or there is no temperature differential. In this scenario, my friend relied on using his TI but quickly learned to revert to traditional search techniques.
OTHER CHALLENGES
Underground applications for TI use also have additional challenges.
- Reflections and false readings: TIs can be sensitive to reflections and heat signatures from surrounding objects and recently driven vehicles from tires, brakes, and engine compartments. In underground parking garages, reflective surfaces like vehicle window glass, metal structures, or glossy concrete walls can create false readings that may mislead firefighters.
- Dense smoke: Smoke in an underground environment can be thick and dense, which can limit the effectiveness of TIs. The TI’s ability to penetrate through heavy smoke can be reduced, making it challenging to identify heat sources accurately.
- Structural obstacles: Underground parking garages can have a complex layout with multiple levels, pillars, ramps, and other structural elements like lighting, ventilation, plumbing systems, security fencing, and barriers. These obstacles can obstruct the TI’s field of view, preventing firefighters from gaining a comprehensive understanding of the fire’s location and spread.
- Heat transfer: The nature of the underground environment means that heat can transfer through various surfaces, such as concrete walls and floors. This can cause a diffusion of the heat signature, making it harder for TIs to pinpoint the exact source or location of the fire.
It is important for firefighters to be aware of these challenges and use TIs in conjunction with other firefighting and search techniques to ensure effective fire suppression and safety in underground parking garages. It is hard to train for every scenario that challenges the fire service, but knowing how your TI works and understanding image interpretation are important.
MANFRED KIHN is a 19-year veteran of the fire service, having served as an ambulance officer, emergency services specialist, firefighter, captain, and fire chief. He has been a member of Bullard’s Emergency Responder team since 2005 and is the company’s fire training specialist for thermal imaging technology. He is certified through the Law Enforcement Thermographers’ Association (LETA) as a thermal imaging instructor and is a recipient of the Ontario Medal for Firefighters Bravery. If you have questions about thermal imaging, email him at Manfred_kihn@bullard.com.
