Zaps of static electricity are a familiar occurrence in our daily lives, those surprising jolts that accompany moments like rubbing socks on a carpet or running a plastic comb through our hair. But could these seemingly harmless sparks have the potential to ignite a fire?
Static electricity arises from an imbalance between negative and positive electrical charges in an object. These charges accumulate on an object’s surface until they seek release. The most prevalent cause of static electricity is the intriguing phenomenon known as triboelectricity.
Pourya Shamsi, a power electronics engineer at the Missouri University of Science and Technology, explains that when two materials come into contact and then separate, one material’s surface can pilfer electrons from the other. This explains why everyday actions like rubbing a balloon on your shirt generate an electric charge. Essentially, negative electrons migrate from one object to another. The subsequent shock occurs when the surplus electrons swiftly depart upon touching another object, like your unsuspecting cat or dog.
The grand spectacle of static electricity on Earth unfolds in the form of lightning, the most powerful display of this phenomenon, notes Shamsi. Collisions between rain droplets and ice crystals within clouds generate immense static electricity. Lightning discharges can carry up to “5 gigajoules of energy, enough to set multiple trees on fire in an instant,” he adds.
Comparatively, the static charge that builds up on a person is minuscule, measuring around 40 millijoules of energy — roughly equivalent to the energy consumed by a typical LED indicator light in one second. However, even this seemingly negligible amount of energy holds the potential to wreak havoc by damaging sensitive electronic devices or, in extreme cases, starting a fire.
Most incidents of static electricity-induced fires involving humans occur in the presence of flammable fuel vapors and gases, according to Shamsi. Gas pumps, particularly at fuel stations, present a common scenario. Static electricity on a person can discharge as an electric spark, capable of igniting flammable material on a pump handle. To mitigate the risk, you can touch metal or the car door with your bare hand before using the pump to discharge static electricity and prevent potential fires.
Beyond gas stations, static electricity poses risks in industrial settings as well, where it can ignite fine dust particles, such as wood dust, aluminum dust, or wheat flour. Shamsi emphasizes that powders and other materials moving around within a facility can lead to static electricity buildup on surfaces, which then discharges onto the dust, causing it to burn.
