Generation and Control of Static Electricity in the Human Body
In daily life, people often accumulate static electricity due to factors such as clothing, climate, and friction. Suddenly touching metal can cause a painful electric shock, which can even cause psychological stress. Temporarily avoiding contact with metal objects can cause further accumulation of charge, leading to a more severe shock.
The human body has a very low resistivity, making it a conductor. When wearing insulated shoes or standing on an insulated floor, the body can become charged through contact. The body can also become charged through induction and conduction through contact with other charged objects. The most common way for clothing to become charged is through clothing.
Common processes of human electrification are as follows:
(1) When a person stands up from a chair or wipes a wall (the initial charge separation occurs on the outer surface of clothing or other related objects, and then the human body is charged by induction.
(2) When a person walks on an insulating floor such as a carpet made of high resistivity material (the initial charge separation occurs between the shoes and the floor, and then, for conductive shoes, the human body is charged by charge transfer; for insulating shoes, the human body is charged by induction).
(3) Static electricity when taking off outer clothes. This is contact electrification between the outer layer of clothing and the inner layer of clothing, and the human body is charged by charge transfer or induction.
(4) When a liquid or powder is poured out of a container held by a person (the liquid or powder takes away a charge of one polarity and leaves an equal amount of opposite polarity charge on the human body.
(5) Contact with electrically charged materials. For example, when sampling highly charged powders. When there is a continuous electrification process, the maximum potential of the human body is limited to about 50kV due to charge leakage and discharge. Control of human body electrification (1) In workshops with explosion-proof requirements, insulating floors such as plastic and rubber should not be used and should be kept as moist as possible. Operators should wear anti-static shoes to reduce human body electrification. If carpets are laid, they should be woven with metal wire and connected to grounding bodies such as water pipes to quickly conduct static electricity. (2) In flammable and explosive places, workers should not wear clothes made of synthetic fiber fabrics. (3) Seats in flammable and explosive places should not be made of high-resistance materials such as artificial leather. (4) High-voltage charged bodies should be shielded, and the human body should avoid being close to high-speed jets of gas to prevent electrostatic induction.