Putting off fire with sound? Sounds unbelievable…

Two engineering students of George Mason University in the United States have made a prototype of a sound device that can put off flames

Hyderabad: To extinguish fire, what do we generally do? Pour water or chemical retardants on it and cut off its fuel. But, ever heard of putting off the fire with sound? Sounds unbelievably, unbelievable…

Two engineering students, Seth Robertson and Viet Tran of George Mason University in Fairfax, Virginia, have come up with an innovative way to put off flames from sound.

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Started with a mere idea for their research project, the duo successfully made equipment, which works for all kinds of fire. They have also applied for a patent this November, which gives them ample time to test their invention to put off kitchen fires and even a spacecraft fire (It is quite a tough task to put off a fire in spacecraft as the extinguisher contents — either in water or chemical form — flies in all directions due to lack of gravity, while gravity has no effect on sound).

How sound works on fire?

According to Robertson and Viet Tran, oxygen is the fuel for fire, and sound waves at certain frequencies can separate oxygen from fire. Sound waves, which are also known as pressure waves, have the potential to influence both burning material and the oxygen that surrounds it. If the sound could be used to separate the two, the fire would be starved of oxygen and could be put off.

Based on this basic principal of sound waves, the two started with ultra-high frequencies of sound on minor fires. Neither could the constantly high sound volume nor the musical one (which is inconsistent), worked on fires. So, they reduced the sound frequency and found that lower and bass frequencies between 30 hertz and 60 hertz, can produce the desired extinguishing result.

There prototype consists of an amplifier and cardboard collimator to focus the sound and cost them only $600. It is hand-held, powered by electricity with the capacity to quickly put out small, alcohol-fuelled fires.

They originally thought of a tool to attack kitchen fires and eliminate the toxic chemicals used in commercial fire extinguishers. Now they see more uses – in confined areas in space, or wide areas outdoors, such as forest fires. Further, not having to waste water or use chemical foams would be a bonus for all.

Challenges

Probably, the main challenge the two inventors will face is the heat inherent in larger fires. As the sound extinguisher contains no coolant, it may not be able to prevent larger fires from reigniting after the sound is turned off.

Besides, the amount of power needed to deal with bigger fires even the one like a couch on fire or electrical equipment need to considered.

Meanwhile, they also have plans to use robotics where the device would be attached to a drone, to be used in situations such as large forest fires or urban blazes, thereby ensuring safety for firefighters.

It is just the kind of thing we need seeing the level of havoc wildfires such as the recent Los Angeles fires have wreaked. In the recent years, wildfires have gone worse, consuming vast acres of forest lands and human habitations. And researchers believe that climate changes will bring in more ‘fire weathers.’