The Generation and Control of Static Electricity in the Human Body
In daily life, due to clothing, climate, friction, and other factors, static electricity often accumulates on the body. When this static electricity is suddenly touched by metal, it can cause a painful electric shock. Frequent occurrences can even lead to psychological stress. Temporarily avoiding contact with metal objects may cause the charge to accumulate further, eventually resulting in a stronger shock.
The human body has a very low resistivity and can be considered a conductor. When wearing insulated shoes or standing on an insulated floor, the body can become charged through contact. The human body can also become charged through induction and through conduction from contact with other charged objects. The most common cause is static electricity from clothing.
Common processes of static electricity accumulation on the human body include:
(1) Standing up from a chair or wiping a wall (initial charge separation occurs on the outer surface of clothing or other related objects; then, the body becomes charged through induction).
(2) Walking on an insulating floor made of high-resistivity materials such as a carpet (initial charge separation occurs between the shoes and the floor; then, for conductive shoes, the body becomes charged through charge transfer; for insulating shoes, the body becomes charged through induction).
(3) Static electricity when removing outer clothing. This occurs through contact charging between the outer and inner layers of clothing; the body becomes charged through charge transfer or induction.
(4) Pouring liquid or powder from a container (the liquid or powder carries away one type of charge, leaving an equal amount of opposite charge on the body).
(5) Contact with charged materials... Material contact. For example, when sampling highly charged powders. When there is a continuous charging process, due to charge leakage and discharge, the highest potential of the human body is limited to below approximately 50kV.
Control of Human Body Charging
(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 charging. If carpets are laid, they should be interwoven with metal wires and connected to grounded bodies such as water pipes to quickly discharge static electricity.
(2) In flammable and explosive areas, workers should not wear clothing made of synthetic fibers.
(3) Chairs in flammable and explosive areas should not be made of high-resistivity materials such as artificial leather.
(4) High-voltage charged bodies should be shielded, and the human body should avoid proximity to high-speed jets of gas to prevent electrostatic induction.