Episode 180: Fire vs. Ice

Air Date: April 1, 2012

A carbon dioxide fire extinguisher can be used to hold off an attack from a flamethrower.

busted

As Jamie built a small-scale flamethrower, Adam tested a standard CO2 extinguisher and found that it could discharge to a distance of 25 ft (8 m), close to the 30 ft (9 m) shown in the viral video that inspired this myth. The two faced off, with Adam walking toward Jamie and deploying his extinguisher. He was able to put out the flames, but had to get within only a few feet to do so.

For a larger test, Jamie built a military-style flamethrower, while Adam made a new extinguisher that used pressurized water to drive the CO2 out and improve the range. At a bomb range, Jamie’s rig achieved a distance of 60 to 80 ft (18 to 24 m), and Adam stood behind a glass shield 60 ft (18 m) away (matching the video) to try and hold it off. A standard extinguisher proved ineffective; Adam’s high-pressure rig did hold the flames back, but only to a distance far below the full 30 ft (9 m). Since they were unable to replicate the video results, they declared the myth busted.

Almost none of the flamethrower construction details were shown on camera. Jamie noted that he and Adam were able to test this myth only under the supervision of several government agencies.

By driving in circles on a dusty road, a group of cars can kick up enough dust to blind a surveillance drone flying overhead. (Based on a scene in the film Body of Lies.)

busted

The Build Team set up a circular practice course to simulate poor visibility in a dust storm and outfitted the cars with various guidance and safety systems. Their first attempts to drive the course ended in failure, but they discovered that the paper they had used to cover the windshields was too opaque. After replacing it with burlap for the correct visibility, Tory, Kari, and two staff members were able to drive the course safely, with Grant coordinating their movements.

On a desert plain, they set up a new circle and placed Kari at its center to act as the film’s kidnapping victim. Tory and three staffers drove around her to kick up dust clouds, after which one pulled up for her to get in and all four drove away in different directions. Grant tried to pick the right car, watching from a helicopter and using a similar camera setup as an actual drone. He succeeded in the first test due to the lack of dust clouds at the center of the circle; however, when the cars drove straight past Kari in a second test, he was unable to pick the one that took her. A repeat of this test, using a thermal imaging camera such as those used on drones, allowed him to find her easily.

Returning to the shop, the team looked into ways to foil the camera system and discovered that a CO2 fire extinguisher could blind it effectively, due to the low temperature of the discharge. One last straight-run test in the desert, with the cars spraying CO2 into the sky, kept Grant from being able to locate Kari. The team judged the myth busted, since the technique in the film did not work, but they noted that the underlying idea could be used successfully under different circumstances.

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