In a makeshift demonstration kitchen in Concord, California, cooking oil splatters in and around a frying pan, which catches fire on an unattended gas stove. Within moments, a smoke detector wails. But in this demonstration, something less common happens: An AI-driven sensor activates and wall emitters blast infrasound waves toward the source of the fire in an attempt to put it out.
The science of acoustic fire suppression, which has long been known and documented in scientific literature and the press, works by vibrating oxygen molecules away from a fuel source, depriving the fire of a critical component needed for combustion. Indeed, after just a few seconds of infrasound, the tiny kitchen blaze goes out.
The demonstration I witnessed took place in the presence of numerous firefighters and officials from Contra Costa County Fire Protection District, the state’s premier wildland firefighting agency (CAL FIRE), and invited journalists. “We were able to not just point-and-shoot like a fire extinguisher; we figured out how to run it through ducting and distribute it like a sprinkler system,” said Geoff Bruder, co-founder and CEO of Sonic Fire Tech, during the presentation.
The company’s goal is to replace sprinklers, which are effective at stopping fires but can also do significant water damage to a property. Sonic Fire Tech appears to be the first company trying to commercialize the science of acoustic fire suppression. Its executives have already been touring Southern California; Wednesday’s event was the first in the northern half of the state.
The company aims to make this infrasound technique mainstream in both commercial (for instance, a data center, where sprinklers would damage electronics) and in-home installations, given that sprinklers are already required in all new California homes built in 2011 and later. Sonic Fire Tech also hopes to produce a backpack-based system that could be worn by wildland firefighters headed out into the field.
But two experts who spoke with Ars raised serious questions about the potential for this technology to supplant traditional sprinklers in a home. They are even more skeptical as to whether the technique can be effective in an uncontrolled wildfire situation, where flames can grow very quickly.
How Acoustic Fire Suppression Works
The principle behind acoustic fire suppression is well understood. Sound waves are oscillations of pressure that propagate through a medium such as air. Low-frequency sound, or infrasound, at frequencies below 20 Hz, can travel long distances and penetrate obstacles. When directed at a flame, these waves disrupt the flow of oxygen molecules near the fuel source. Fire requires three elements: heat, fuel, and oxygen. By vibrating oxygen away from the flame, the combustion process is starved and extinguishes. This phenomenon has been demonstrated in laboratory settings for decades, but only recently has technology advanced enough to produce powerful infrasound emitters that can be integrated into building systems.
Sonic Fire Tech’s system uses wall-mounted emitters that produce infrasound waves at specific frequencies and amplitudes. The system is triggered by an AI-driven smoke and heat detector that can pinpoint the fire location and activate only the nearest emitters. This reduces energy use and ensures that the sound is focused precisely where needed. The company claims that the system can suppress a fire in milliseconds, much faster than the minutes it can take for a sprinkler to activate.
The Demonstration and Company Claims
The demonstration in Concord involved a small grease fire in a frying pan on a gas stove. The smoke detector activated, and within seconds the infrasound emitters turned on. The fire flickered and went out. The entire process was smooth and left no residue. “Traditional residential sprinklers activate several minutes only after heat rises to a threshold, can discharge large volumes of water that damage interiors and electronics, and require plumbing infrastructure that adds cost and complexity,” says a company press release. “Sonic Home Defense, by contrast, deploys in milliseconds and uses inaudible low-frequency infrasound waves to disrupt the chemistry of combustion before flames can spread, with no water, no chemicals, and no risk of flooding the interior of the home being protected.”
Sonic Fire Tech says that its system is as good as, if not better than, traditional sprinklers for many applications. “Sonic Fire Tech is in fact intended to replace interior residential sprinklers,” Pollack told Ars. “The demo showed a critical benefit of SFT over water sprinklers in suppressing a kitchen fire, which represents about half of all residential fires. This is also applicable to commercial kitchen fires and other common grease and chemical fire applications.”
The company also claims to have secured third-party validation of its system as a viable NFPA 13D-equivalent alternative to conventional residential sprinklers. The National Fire Protection Association’s 13D standard is the benchmark for residential sprinkler systems. Sonic Fire Tech says it was evaluated by James Andy Lynch and his team at Fire Solutions Group, a Pennsylvania-based consultancy. The company provided Ars with a two-page executive summary of the report, but declined to release the full document due to confidentiality and patent-pending information. The summary states that “the Sonic Fire Tech system is capable of delivering extremely rapid fire detection, meaningful suppression or extinguishment, and consistent performance across a variety of installation configurations.” However, it also notes that “additional testing and optimization are recommended to further expand the range of validated applications,” and that the products have the “potential to complement or, in certain applications, serve as an alternative to traditional suppression systems.”
Expert Skepticism and Regulatory Hurdles
Despite the promising demonstration, fire safety experts are cautious. Nate Wittasek, a Los Angeles-based fire protection engineer, pointed out critical differences between sound and water. “Sprinklers have a well-established role,” he said. “They apply water directly to the fuel, cool the space, slow or stop flashover, and give people time to get out while reducing risk to firefighters. Sound may knock down a small flame, but it does not cool hot surfaces or wet fuel. That raises real questions about re-ignition, smoldering fires, hidden fires, and fires that are partially blocked by contents.”
Michael Gollner, a professor of mechanical engineering at the University of California, Berkeley, and an expert in fire dynamics, told Ars there’s simply not enough information yet to show that this technology works better than sprinklers. He pointed to a 2018 academic paper, which found that “acoustics alone are insufficient to control flames beyond the incipient stage.” By contrast, “Fire sprinklers are extensively tested and certified by standards developed by the fire safety community over many years,” he said. “I think this product needs to demonstrate the same or better performance with the same reliability before it can be considered to replace any existing safety measure. While I am absolutely supportive of out-of-the-box thinking, lives are truly at stake, and new technologies must carefully demonstrate effectiveness and reliability before being entrusted by society.”
Jonathan Hart, NFPA Technical Lead, Fire Protection Technical Resources, clarified that “Equivalency [to the 13D standard] can only be approved by the appropriate authority having jurisdiction and requires technical documentation be submitted demonstrating the equivalency.” To date, Sonic Fire Tech has not publicly provided this information. Wittasek added that if Sonic Fire Tech is going to claim equivalence, it should provide a whole range of specifics, such as “who validated it, what test protocols were used, what fire scenarios were included, and how success was defined.” He also wants to see full-scale testing that includes typical residential fires like furniture and mattress fires, cooking fires, electrical fires, and attic or exterior ember exposures, as well as different conditions like open and closed doors, varying ceiling heights, crosswinds, obstructed fuel packages, and whether the fire comes back after the system shuts off.
Potential Applications and Future Testing
While the residential market is the primary target, Sonic Fire Tech also sees potential in commercial settings where water damage is especially problematic, such as data centers, museums, and kitchens with grease fires. The company is even exploring a backpack system for wildland firefighters. However, experts are skeptical about the effectiveness of sound in the open, windy conditions of a wildfire.
Deputy Fire Chief Tracie Dutter of Contra Costa County Fire Protection District, which hosted the demonstration, said the agency does not recommend specific products but tries to understand new technology. “Sonic representatives indicated they are exploring opportunities to partner with fire departments to test this technology on a bulldozer,” Dutter said. “The District would be open to testing this system on one of our dozers to better understand its limitations and potential failure points.” Firefighters also want to know about long-term maintenance requirements, routine testing or calibration, and how system failures such as a malfunctioning detector or acoustic generator are identified and communicated to an owner.
As Sonic Fire Tech continues to develop its technology, it faces significant challenges in convincing the fire safety community and building code authorities. The company’s ability to provide transparent, comprehensive testing data will be crucial. In the meantime, water sprinklers remain the gold standard for fire suppression in buildings. The question of whether infrasound can truly replace them remains unanswered, but the technology is an intriguing glimpse into a future where fires might be silenced with sound.
Source: Ars Technica News