Recognizing and Mitigating Static Electricity Hazards
Fire departments respond to nearly 280 industrial incidents involving static electricity each year.
Ancient Greeks discovered that when animal fur and amber were rubbed together, the fur could be used to attract feathers, glass dust and other lightweight objects. It wasn’t until 1600 AD, however, that William Gilbert, an English scientist, documented and associated this property with electricity.
Static electricity is sometimes little more than a nuisance that causes clothing to unattractively cling in all the wrong places. It can be much more detrimental. In fact, fire departments respond to nearly 280 industrial incidents involving static electricity each year, according to the National Fire Prevention Association (NFPA).
Imbalance of Energy
Objects are made of atoms containing protons, electrons and neutrons. Most of the time, the protons and electrons balance each other in an object, making it electrically neutral. But when different objects rub together, that friction can cause the number of protons or electrons on the surface can become imbalanced, creating static electricity.
Static electricity remains on a surface until it is either safely discharged or until it can jump to another object. When it finds a path to jump to another surface, it does so as a spark.
Although it is most often associated with a person walking across a surface and touching another person or a metal object, static electricity can also be generated by materials in motion, such as the movement of fluids. When liquids move through pipelines or hoses, the friction creates static electricity.
Filtering, stirring, pouring and pumping liquids creates static electricity. Like static cling in clothing, this is sometimes little more than a nuisance, but when flammable liquids are being moved, static electricity can cause fires and explosions if sufficient concentrations of flammable vapors are present.
Like friction, humidity plays a role in static electricity hazards. According to the National Oceanic and Atmospheric Administration (NOAA) data, 89 percent of the U.S. experiences at least seasonal conditions where the relative humidity is 60 percent or less. The lower the humidity, the higher the potential for harmful levels of static electricity to build up on surfaces.
This article originally appeared in the May 1, 2020 issue of Occupational Health & Safety.