The yellow rectangle with black "SD" letters on safety footwear signifies that the footwear is static-dissipative, designed to safely control static electricity buildup in environments where such discharges could pose risks to workers or sensitive equipment. This type of footwear is not suitable for situations involving live electrical conductors, as it does not provide electrical insulation.
Key Points Explained:
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Meaning of the Symbol
- The yellow rectangle with "SD" is a standardized marking indicating static-dissipative properties.
- It ensures controlled dissipation of static electricity, preventing sudden discharges that could ignite flammable materials or damage electronic components.
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Intended Use Cases
- Electronics Manufacturing: Prevents static damage to sensitive circuits.
- Chemical & Pharmaceutical Labs: Reduces ignition risks in flammable environments.
- Cleanrooms & Data Centers: Protects equipment from electrostatic interference.
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Limitations & Safety Notes
- Not for Electrical Work: Unlike footwear marked with an orange omega symbol (electrical hazard protection), "SD" footwear does not insulate against live currents.
- Testing Standards: Compliant with ASTM F2413 or EN ISO 20345, ensuring a resistance range (typically 10^6–10^8 ohms) to safely ground static charges.
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Other Common Safety Footwear Symbols
- Toe Protection (Blue/Grey Rectangle): Steel/composite toe caps for impact resistance.
- Puncture Resistance (Green/Yellow Triangle): Midsole protection against sharp objects.
- Metatarsal Guard (Dark Grey "M"): Shields the upper foot from heavy impacts.
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Selecting the Right Footwear
- Assess workplace hazards (e.g., sparks, heavy objects, liquids) to match symbols with needs.
- Combine features if multiple risks exist (e.g., "SD" + toe protection for electronics warehouses).
By understanding these symbols, purchasers can ensure worker safety while meeting industry-specific requirements—whether in a lab handling volatile substances or an assembly line for microelectronics.
Summary Table:
| Symbol | Meaning | Key Use Cases | Limitations |
|---|---|---|---|
| Yellow SD Rectangle | Static-dissipative (controls static electricity) | Electronics manufacturing, chemical labs, cleanrooms | Not for live electrical work; no insulation |
| Blue/Grey Rectangle | Toe protection (steel/composite) | Construction, warehouses | Does not protect against static or punctures |
| Green/Yellow Triangle | Puncture-resistant midsole | Landscaping, recycling facilities | No static or toe protection |
| Dark Grey "M" | Metatarsal guard (upper foot impact protection) | Heavy industrial settings (e.g., metalworking) | Often paired with toe protection |
Need static-dissipative or other safety footwear for your team? As a leading manufacturer of industrial and safety footwear, 3515 produces high-performance shoes and boots tailored to your workplace hazards—from static control to impact resistance. Get a quote for bulk orders or custom solutions, and ensure compliance with ASTM/ISO standards.
