Views: 31 Author: Site Editor Publish Time: 2025-12-30 Origin: Site
1) What is ESD? What is its purpose in safety shoes?
ESD = ElectroStatic Discharge (Static Electricity Discharge/Protection).
When walking, friction between the sole and the ground, as well as between materials inside the shoe, continuously generates static electricity.
If static electricity accumulates to a certain level, a person can discharge it with a "snap" upon touching metal, equipment, or electronic components (similar to getting a shock from a doorknob in winter).
The main purposes of ESD in safety shoes fall into two categories:
Protecting Electronic Products/Precision Equipment
For example, in electronics factories, chip manufacturing, instrumentation, and assembly lines. Static electricity on the human body can damage components (often invisible to the eye but harmful to the product).
Reducing Spark Risk (More Common in Industrial Scenarios)
In environments with flammable solvents, dust, or oil vapors, sparks generated by electrostatic discharge pose a potential hazard.
The core function of ESD shoes is: to prevent static electricity on the human body from accumulating to a high level and discharging suddenly. Instead, they allow it to be "slowly and continuously dissipated to the ground."
Therefore, you can think of ESD shoes as:
"Providing a controlled dissipation path for static electricity on the human body, preventing it from accumulating excessively."
2) What does 'Resistance Too High' mean? Why does it cause ESD failure?
Resistance (Ω, ohms) can be understood as the ease with which current flows.
High resistance = Very difficult for current to flow = Closer to an "insulator"
Low resistance = Easy for current to flow = Closer to a "conductor"
The requirement for ESD shoes is not to be conductive like a wire, but to achieve a "just right" range:
Cannot be too insulating: Otherwise, static electricity cannot dissipate and will keep accumulating.
Cannot be too conductive (some standard systems set a lower limit): To avoid other safety risks from being "overly conductive."
Your report shows: Whole shoe resistance > 2×10⁹ Ω, with the requirement being ≤ 1×10⁸ Ω.
In simple terms, this means:
"These shoes are too insulating. It is very difficult for static electricity to dissipate from the human body through the shoes to the ground, so static will accumulate, resulting in ESD failure."
A simple analogy:
The ground is the "drain."
Static electricity is the "water."
ESD shoes should act like "drainpipes with some resistance."
Currently, your shoes have too high resistance, equivalent to "the drainpipe being blocked/not connected at all," so the water cannot drain and keeps accumulating.
3) In an ETPU + Rubber sole structure, why is high resistance common?
Because these materials are mostly naturally insulating:
ETPU Foam Midsole: Essentially an insulator (the foam cell structure also makes it harder for electricity to travel).
Multi-colored Rubber Outsole: Especially colorant systems like blue/red, are often more "insulating" than black.
Adhesive/Primer Treatment: Many form an "insulating film," isolating parts that might otherwise be conductive.
Therefore, the common failure cause is often not "materials being slightly off," but rather:
There is no continuous conductive path from the foot → insole/midsole → outsole contact surface.
Even if part of the outsole is slightly conductive, if the path is "broken," the whole shoe test will show a very high resistance.
4) A one-sentence summary of the role of ESD in safety shoes
ESD safety shoes = Anti-static "dissipation shoes" that allow static electricity generated by the human body to be continuously and controllably released to the ground, preventing static accumulation that could cause electronic damage or discharge spark risks.
Resistance too high = Shoes too insulating = Static cannot dissipate = Non-compliant.
