Fighting Fire with Sound: Wave Extinguisher
Two former U.S. electrical engineering students have discovered a cutting-edge and unconventional way to fight fires: with sound. Specifically, bass frequencies between 30 and 60 Hz.
While the concept of extinguishing flames with waves is not completely new, a handheld extinguisher had yet to be developed and mass-produced. Seth Robertson and Viet Tran – at the time, both final-year undergraduates at George Mason University in Virginia – explained they decided to take an “Edison approach” to their research in working with sound waves, using each failure to learn something until they created a successful prototype.
Previous attempts to use ultrasound as a tool against flames – including efforts by the U.S. Defense Advanced Research Projects Agency (DARPA) – had proven unsuccessful and the two students were met with skepticism from peers and faculty when choosing this as a research project. They explained that they put quite a bit of time and money into exploring ultrasound as the solution, with little success, and even lost most of their student team when a solution seemed unattainable.
However, when they discovered the power of the bass frequency in putting out the flame, their perseverance paid off. Since sound waves can move oxygen and fire through pressure from their vibrations, this specific frequency of sound wave works to separate the flame molecules from the surrounding oxygen, effectively starving the fire and snuffing out the flame.
While there is some risk of the fire reigniting once the oxygen returns to the area (aka, when the device is turned off), the potential benefits are extensive: users would not be exposed to potentially toxic chemicals found in some extinguishers, nearby equipment could be damaged, and other people could be impacted. Acoustic fire suppression technology is clean and efficient, and devices never have to be “refilled.”
The students’ final hand-held, mains-powered prototype, built for around $600, made quite a stir on the Internet and in scholastic circles thanks to its popular YouTube demonstration. Although originally developed with household fires in mind, other potential uses for the device’s technology include wildfire settings, automotive shops, in firefighting drones, or mounted in arrays on top of a fire truck.
An additional use case for the sound wave extinguisher could be outer space, where fire poses a huge problem. Since traditional extinguishers used in zero gravity spray contents in all directions, it’s incredibly difficult to target a flame. But since sound waves can be directed without gravity, using the bass frequencies could be an ideal solution.
The students explained that the frequency range used in their technology is within a safe range – unlike weaponized acoustic devices used for riot control or other harmful ways – is completely safe for humans and wildlife.
After graduating, Robertson and Tran formed the company Force SV to continue exploring commercial development of their invention. In February 2019, partnered with ARSAC Technologies, Inc. to implement the technology into multiple applications.
Fire departments across the U.S. are continuing to explore new ways to leverage technology like acoustic fire suppression and unmanned drones to find creative and effective ways to fight fires, expand search and rescue, and ultimately reduce risk for both firefighters and the community. Within the fire station, easy to use fire-specific software tools can similarly increase efficiencies and leave more time for innovation, training, and quality improvement. For more information on software designed specially for use by firefighters, visit eso.com/fire.