The prototype extinguisher uses waves produced by a low-frequency sound:
The technology is based on the way sound waves displace oxygen as they move through physical space—oxygen that fire feeds on. If you can suffocate a fire, you can extinguish it, so the pair set to work. They discovered that music is unsuitable—the sound waves it produces are inconsistent. A higher frequency sound caused the flames to vibrate, but that was all. The lower frequencies—30 to 60 hertz—seemed to be the so-called “Goldilocks zone” at which the waves were able to effectively keep the oxygen from the flames long enough to suffocate them, CNET said on their website.
DARPA’s device back in 2012 was not something you could easily move around. This new prototype is a portable handheld extinguisher. It consists of a sound frequency generator, a small amplifier, and a collimator made out of a cardboard tube to focus the waves in a specific direction.
The inventors have even more dreams for their new flagship, The Washington Post reports: “Robertson and Tran envision their technology being used to put out fires in homes—and in the wild. If properly scaled, sound-wave extinguishers would eliminate the need to douse forests in chemicals, or waste untold gallons of water.”
The extinguisher was able to extinguish a small, controlled fire with an alcohol accelerant.
This proves that the concept is viable. There are further developments needed, but it’s a start. According to The Washington Post, a local fire department has requested testing the extinguisher on a structure fire.
The days of remembering which fire extinguisher to use on what fire may soon be over.