What Is an Electrostatic Shoe?
ESD (Electrostatic Discharge) shoes are safety footwear used to prevent accidents caused by electrostatic discharge.
When people walk or do other activities, they are charged by electrostatic induction caused by friction between clothing and other objects.
This phenomenon means that unless some measures are taken, people are always in a dangerously charged state that can trigger ignition of flammable materials or electric shocks. To avoid this, it is simple and effective to wear ESD shoes that allow static electricity generated to escape from the soles to the floor so that it does not accumulate on the human body.
It is important to note that it is difficult to maintain the original performance of ESD shoes if the soles are worn out or coated, so a visual check before use is the first step to safety.
Uses of ESD Shoes
ESD shoes are used in three major ways.
The first is for use in places where static electricity may cause accidents or disasters such as explosions, fires, and electric shocks. Examples include: Various factories that handle flammable materials such as petroleum, chemical, painting, printing, etc.
The second is for use in locations where production disturbances such as damage or contamination of electronic elements caused by static electricity may occur. Examples include: electronics manufacturing plants.
The third is use under high voltage, such as inspection of high-voltage electric cables.
Since inspection of high-voltage electric cables must be performed without fail even in winter, safety shoes are designed for use in 0°C environments.
Principle of ESD Shoes
In order to maintain the human body at a safe level of electrification, the generated static electricity must escape to the floor within a few hundred milliseconds, and the charged potential of the human body must be suppressed to several 10V or less.
- General ESD Shoes: 1.0 x 10^5 ≤ R ≤ 1.0 x 10^8 (1.0 x 10^5 ≤ R ≤ 1.0 x 10^9)
- Special ESD Shoes: 1.0×10^5≦R≦1.0×10^7 (1.0×10^5≦R≦1.0×10^8)
- Conductive Shoes: R<1.0×10^5 (R<1.0×10^5)
*Measurement temperature: 23°C±2°C, values in parentheses are reference values under 0°C environment.
Furthermore, since humidity is also an important factor in the generation of static electricity, products that meet the criteria for use in dry conditions with lower values at three levels of humidity (12±2%, 25±3%, and 50±5%) are considered to be more stable ESD shoes.
Although it is difficult to explain the numerical value, it can be simply described as a very cost-effective safety shoe that releases static electricity generated in the human body instantly from the insole of the shoe → inner sole → conductive path of the sole → sole of the shoe → ground.