Electrostatic discharge, commonly referred to as ESD, is the spontaneous flow of energy between two objects when both have been electrically charged by static electricity, electrostatic induction, or in some cases electrically charged particles striking an object. These types of energy transfers have been around since the beginning, but ESD has only become an issue since the creation of intricate circuits present in much of the technology existing today.
The imbalance of positive and negative charges is what creates electrostatic discharge. Insulators and conductors, both of which are thrown into the broad spectrum of the triboelectric series, are sources of ESD. With the buildup of either positive or negative charge, the need for the charges to equalize and ground themselves results in a discharge of energy that can be recognized by a spark jumping from one object to another. However, ESD can occur even without seeing that tell-tale sign of a spark. This becomes a problem for machinery and other equipment because ESD causes the internal electrical components to suffer heat damage when unseen ESD problems persist.
Physical sparks occur when the electric field strength is more than 4-30kV/cm which is the dielectric field strength of air. Once the field strength reaches that point, a rapid increase of free electrons and ions appear in the air which causes the air itself to become an electrical conductor for a short amount of time which causes that spark.
ESD events and can cause terrible explosions in the right conditions. Think of it as mini lightning since what you see normally on a stormy day is technically a source of electrostatic discharge, just on a massive scale. As seen from that example, ESD is a prime contender for an ignition source in areas that may have high concentrations of flammable gases as long as the upper explosive limit (UEL) has not been exceeded. Employees absolutely must take precautions during these situations and have the correct equipment to prevent catastrophic ESD occurrences.
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