By Ivan Raconteur
Thermal imaging cameras allow firefighters to do more, safely
LESTER PRAIRIE, MN In addition to saving the lives and property of residents, keeping firefighters safe is a top priority for the Lester Prairie Fire Department.
Two new thermal imaging cameras donated to the city by the Lester Prairie Fire Department Relief Association are helping the department do just that.
Fire Chief Jim Hoof said the smaller of the two hand-held units goes with the first truck to the scene of a fire.
It helps firefighters to quickly assess the situation.
“It definitely is safer than going in blind,” Hoof commented.
The larger unit, which has a larger screen and faster refresh rate, is taken in by the attack team when they enter a structure.
Hoof explained that these cameras do not provide “X-ray vision,” and they cannot see through walls or obstructions into other rooms.
What they can do is help firefighters see if there is a person down in a smoke-filled room.
They can also identify hot spots in walls, floors, or ceilings.
Hoof explained it is also very important for firefighter safety.
“It’s way different than when I started,” he said. “They used to have solid floor joists, and you could walk into a building 20 minutes after it was on fire. They aren’t safe to go into anymore. Now, you’ve got four or five minutes, and the structure is starting to burn away.”
Newer, lighter construction materials burn more quickly. Even if the plywood flooring appears safe, the supporting materials underneath may have burned through.
Chief 3 Matt Tonn added that many of the new materials include a lot of glue, which burns very quickly compared to solid wood.
Hoof and Tonn noted there have been cases in which a carpet was the only thing holding a floor up, because the underlying materials burned so quickly.
The thermal imaging cameras allow firefighters to detect weak spots, which helps to keep them safer.
“We want to be aggressive,” Hoof commented, “but we want to be cautiously aggressive.”
Once a fire is out, the cameras can eliminate the need for firefighters to do additional damage tearing out Sheetrock to check for hot spots, Tonn said.
Hoof noted that because newer construction falls into a heap so quickly, it can be difficult to find all the hot spots.
“You don’t want to tear everything apart,” Hoof said, “because then the investigators have a tough time pinpointing where the fire started, so you try to leave as much intact as you can.”
Using the cameras to find hot spots, which cuts down on the need for callbacks.
Tonn demonstrated the sensitivity of the equipment. Following someone walking across the floor, it is possible to see the heat signature of their footprints temporarily.
If a person holds his hand against a wall for a moment, and removes it, the cameras can detect the handprint because of the temperature difference.
For another experiment, Tonn turned on a pizza oven. Looking at it from across the room, it stood out dramatically on the screen because of the higher temperature.
The display on the camera includes a temperature display, and the colors of objects in the display change as heat increases.
In addition to fires, the cameras have other applications for the department.
Hoof said if responders arrive on the scene soon enough after a motor vehicle crash in which occupants were thrown from the vehicle, the cameras can be used to scan the seats in the vehicle, and can detect the heat profile where people were sitting so emergency responders know how many people they are looking for.
The cameras can also be used to assist in the search for missing people (or suspects who may be trying to evade law enforcement officers).
Although the cameras cannot detect people behind walls or obstructions, they can detect people in open areas or, for example, in a field of tall grass.
Hoof said the department has already used the cameras in a drill searching for people in Sunrise Nature Park on the east side of Lester Prairie.
The new cameras are not the first for the department.
The department’s previous thermal imaging camera is now 16 years old. It is larger, heavier, and more difficult to use.
When that camera was purchased in 2000, the list price was $25,000. The department was able to purchase it on close-out for $18,600.
In contrast, the two cameras that were purchased last fall use much newer technology, and were less expensive. The displays have faster refresh rates, and they are more user-friendly than the old model.
The larger unit cost $4,200, and the smaller cost $1,300.
Hoof explained the relief association purchased the cameras with the proceeds from the department’s annual firefighters dance.
“Each year, we like to have a project,” Hoof explained. “In 2016, we decided to look at a new thermal imaging camera.”
The relief association purchased the cameras and donated them to the City of Lester Prairie.