Static electricity from clothing

Many people s reaction would have been that this is another of those accidents that we can do nothing about, another occasion when man told to take more care appears on the accident report. 

However, in the plant where the accident occurred, they were not satisfied with this easy way out. They looked into the accident more thoroughly. The injured man was asked why he had not used the handrails. 

It then came to light that the handrails were covered with plastic and that anyone using them and wearing insulating footwear acquired an electric charge. When he touched the metal of the plant, he got a mild electric shock. The spark, of course, was not serious enough to cause any injury. But it was unpleasant. People therefore tended not to use the handrails. 

For a spark to be felt, it must have an energy of at least 1 mJ. The minimum energy required to ignite a flammable mixture is 0.2 mJ, so a spark that can be felt is certainly capable of causing ignition if flammable vapor is present. 

When he was about to replace the cap on the end of the filler pipe, a spark jumped from the cap to the pipe, and a flame appeared on the end of the pipe. It was soon extinguished. The flame could not travel back into the gasoline tank. The mixture of vapor and air in the tank was too rich to explode. 

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Figure 14-3 A circuit with a battery and a resistor. Benjamin Franklin investigated static electricity in the 1740s. 1 He thought electricity was a fluid that flows from a silk cloth to a glass rod when the tod is rubbed with the cloth. We now know that electrons flow from glass to silk. However, Franklin s convention for the direction of electric current has been retained, so we say that current flows from positive to negative—in the opposite direction of electron flow...

The term static electricity is understood to mean a high-voltage low-current electrical discharge in the form of often visible sparks caused by contact and separation of dissimilar nonconductors and also of insulated conductors of electricity. It is nowadays in constant evidence in connection with synthetic plastic films and fibers and also with wool and silk used in clothes, carpets, upholstery materials, etc. In the case of dusts, static electricity is created by the movement of the particles, and certain sensitive metal powders can ignite by being poured from a sheet of paper or plastic film. Low relative humidity favors buildup of static electricity. 

People who make and handle fireworks wear cotton clothes (down to their underwear) because the static electricity generated from synthetic fibers can ignite fireworks. 

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