This Device Could Put Out Fires Using Nothing But Low-Frequency Sound Waves

26 Feb 2025

Operating at 30-60 hertz, the sound extinguisher douses flames in just seconds. (Image Credit: George Mason University/YouTube)

Back in 2015, two engineering students at George Mason University developed a fire extinguisher that puts out fires using low-frequency sound waves. It only takes seconds to extinguish a fire. Their device can be attached to a drone, potentially improving safety for firefighters fighting urban blazes, forest fires, or space.

Seth Robertson and Viet Tran came up with this concept when choosing a class project for ECE 492 and 493, Advanced Senior Design. The pair spent $600 to develop the 20-pound prototype, which underwent a year of trial and error before being made into a fully functional device. The sound-wave fire extinguisher doesn't contain toxic chemicals and eliminates collateral damage from sprinkler systems.

While researching ideas for the project, Tran discovered that DARPA worked on a similar idea, and George Mason University was working on “Prometheus.” That sparked innovation for Tran, who decided to tackle the project.

It features a frequency generator, power supply unit, vortex nozzle, cardboard collimator, acoustic output, IR sensor, and an audio amplifier. They also used an oscilloscope to measure the frequencies during tests. The collimator’s vortex ring enables longer sound wave travel with minimal energy loss. Meanwhile, the IR sensor uses a fire’s wavelength to detect flames.

So, how does it work? Sound waves function like pressure waves, displacing some oxygen. You just need a certain frequency to separate the oxygen in the fire from the fuel. The pressure wave moves back and forth, agitating the air, sufficient to prevent fire reignition.

Robertson and Tran originally thought large speakers and high-frequency sound waves could eliminate fires. "But it's low-frequency sounds—like the thump-thump bass in hip-hop that works," says Tran. At the time, they tested 20,000 and 30,000 Hz. But that caused the flames to flicker. The sweet spot is 30-60 Hz to douse the flames.

"Fire is a huge issue in space," Tran says."In space, extinguisher contents spread all over. But you can direct sound waves without gravity," adds Robertson.