Dangers of ElectroStatic Discharges

Additionally to provoking sudden failure or even worse, latent faults to electronic components in equipment there is danger to persons, directly or indirectly. The latter may occur indirectly eg an ESD event fails a crucial electromechanical device, for example in an aircraft, car, submarine, etc... but also sparks in between charged conductors eg a person or metallic objects, may initiate other catastrophic type of events like fire and explosions whilst in the vicinity of volatile ignitable products like gas, fuel, etc... these are usually strong capacitive sparks. In industrial workplaces it is not unusual to have operating belt drives which if not ESD controlled may accumulate large amount of charges due to their triboelectric interactions with the metallic rollers. Ensure there is no flammable or explosive materials in locations where ESD cannot be fully controlled .

There are some documented incidents in the USA where motorcar fuel has ignited due to ESD sparks, hence seriously injuring people. It has been learnt that whilst filling a metallic can with gasoline at a service station is recommended to have the can firmly placed on the ground while doing so, any accumulated charges around the body of the can will neutralise consequently avoiding sparks, explosions have occurred where the can has been placed on an insulating plastic mat on a pick up truck. This is similar to the reason why aviation procedures specify that a loading fuel truck must be connected by an electrical wire to the metallic structure of the plane being refilled so as to ensure them to be at the same potential.

The US Chemical Safety and Hazard investigation Board (Washington) informed the press in June 2003 that the well known Kinston explosion at the West Pharmaceutical Services that killed six workers and injured dozens in the manufacturing of rubber products section was due to fine dust plastic powder mixed with air. The area affected by the explosion was where rubber sheet strips where coated with moisten polyethylene, hence the formation of the explosive mix (there was a suspended false ceiling where the mix accumulated out of check, this is a bad design for ignitable gases). The investigation is still going on an a final report is expected soon. The investigators agree that the polyethylene powder recovered from the explosion site is in fact explosive, once mixed with air.