Inaudible sound might be the next frontier in wildfire defense

A decade ago, an innovative concept emerged when two college students developed a fire extinguisher that utilized a powerful 10-inch subwoofer to extinguish flames. This idea captured widespread attention, even earning a spot on The Tonight Show with Jimmy Fallon. However, since that initial surge of interest, the technology has largely faded from public view, despite ongoing research and development. Pioneering efforts in this realm date back to 2012 when DARPA first explored the potential of sound in fire suppression. Numerous researchers have continued to investigate this groundbreaking idea, leading to the emergence of a startup that claims to have made significant strides. Sonic Fire Tech has engineered an acoustic fire suppression system that not only extinguishes flames but also aims to safeguard structures from wildfires. Recently, the startup secured a $3.5 million seed investment from prominent backers, including Khosla Ventures and Third Sphere, as reported by TechCrunch. The financial toll of wildfires in the U.S. can reach up to $424 billion annually. The situation has become dire in states like California, where insurers are increasingly hesitant to renew policies following devastating fires that have ravaged large areas. Sonic Fire Tech has spent years refining its technology, spearheaded by Michael Thomas, the board chairman, who first conceptualized using sound waves to combat fires. After encountering challenges, he connected with Geoff Bruder on LinkedIn, who brought expertise from his NASA background in heat and acoustics. Bruder, now the CEO and CTO, found the idea compelling and began constructing a prototype. Using readily available materials, Bruder recalled creating a working model in his driveway, successfully extinguishing a fire from just seven feet away. As development progressed, the team moved away from traditional subwoofers to focus on lower frequencies. Bruder explained that audible frequencies could pose risks to hearing, necessitating a complete redesign of their approach. While the precise mechanisms by which sound waves can interfere with combustion remain a topic of debate, Sonic Fire Tech's silent demonstrations hint at a promising breakthrough. Their innovative system utilizes a large reciprocating piston, similar to those found in car engines, powered by an electric motor that generates infrasound—sound vibrations below the human hearing threshold of about 20 Hz. This design allows for safer and more effective transmission of sound energy, achieving a current operational range of 25 feet, with potential for expansion to 330 feet with larger systems. The startup plans to offer installations priced at approximately 2% of a home's value and is actively engaging with insurance companies to validate their technology. To provide protection, Sonic Fire Tech directs infrasound generated from a single unit through rigid ducts located along the roof’s edges and eaves, targeting potential fire sources in gutters and near walls. The system activates automatically when sensors detect flames, drawing around 500 watts of power, with plans for lead-acid battery backup during outages. Unlike traditional sprinkler systems, this technology does not rely on water, making it particularly advantageous in fire-prone areas. Sonic Fire Tech is collaborating with Pacific Gas and Electric and Southern California Edison to demonstrate its technology in residential settings, and has also signed a letter of intent with a chemical storage facility. Bruder envisions future applications, stating that once the system is certified as a sprinkler replacement, it could be integrated into homes for comprehensive fire protection.