Just as the snow began to pick up Tuesday morning, a writhing plume of smoke slithered up from a steel structure in an industrial corner of Salt Lake City. When the fire engine pulled up, a four-person crew jumped out, tugging leaky hoses across the freezing pavement. Clad in oxygen masks and yellow coats, the firefighters stepped through the door and vanished into the smoke.
What looked like a multi-alarm fire was actually a drill designed to test three new thermal imaging cameras. Salt Lake Fire Capt. Kelly Carter said his department has been using the cameras for about 10 years, but that the technology has advanced. Tuesday's drill was staged to explore possible upgrades to smaller cameras with more powerful features.
"We're trying to move to the next generation," he said.
The new cameras evidently worked. Moments after the four men charged into the burning structure, they emerged from a different door dragging a fifth firefighter. The man had been playing the role of a fire victim, and smoke curled off his uniform as he was pulled from the building.
Capt. Chris Milne operated the thermal imaging camera during the search for his "victim," navigating a 1,280 square foot structure made from old shipping containers. The building is cramped, dark and smells like a campfire even when nothing is burning. During the drill, crews burned pallets and other wood material in order to fill it with smoke, floor to ceiling.
Milne said that when firefighters go into a burning structure they still rely on typical firefighting techniques staying close to the ground and hugging the walls, for example but the cameras allow them to see where they are going and locate victims more quickly.
"They give us more opportunities to save someone," he added.
As the name suggests, thermal imaging cameras function by scanning for heat signatures. Those signatures are rendered into black and white images with different shades of gray representing different objects. When Carter pointed the camera at a group of firefighters, for example, their faces glowed white representing a relatively warm spot while their uniforms appeared darker.
Carter also pointed the camera at a snow-covered roof, fire hoses on the frozen ground, and a gloved hand. In each case, the cameras captured subtle differences in temperature: thinner parts of the glove glowed brighter, the water-filled hoses were distinct from the ground, and the roof appeared grayer near the edges where the snow was thinnest and melting.
In a burning building, Carter explained, the cameras' ability to distinguish between people and inanimate objects gives firefighters eyes when visibility is non-existent.
"It will, in a sense, see through the smoke," Carter explained.
The images produced by the cameras are displayed on a small screen on the back of the device. During Tuesday's drill, crews tested three new cameras, all of which had a slightly different appearance. However the overall effect was somewhere between a large camcorder and a sci-fi laser gun.
At least one of the cameras tested Tuesday was produced by Pennsylvania-based Mine Safety Appliances and is sold locally by Weidner Fire. Troy McBride, a representative for Weidner Fire, said thermal imaging cameras typically cost between $10,000 and $14,000. They're so sensitive, he noted, that they can pick up the residual heat from a foot sliding along the frozen ground. McBride added that the cameras are also sometimes used at accidents to determine how many passengers were in a car; they can detect body heat on a seat, even after a person is no longer sitting in it.
Carter did not know which of the three cameras his department would purchase, if any, and said that decision will be made based on reports about Tuesday's drill.