What Are The Different Safety Classes Under En Iso 20345? A Guide From Sb To S5

The primary safety classes under EN ISO 20345 are SB, S1, S1P, S2, S3, S4, and S5. Each classification builds upon the previous one, adding specific protective features designed to mitigate risks in different work environments. This system provides a clear hierarchy of protection, starting from basic toe impact resistance (SB) and advancing to fully waterproof boots with penetration-resistant midsoles (S5).

The fundamental principle of the EN ISO 20345 standard is to match the level of protection to the specific hazards of a job. Understanding that the classes are cumulative—where S3 includes all the protections of S2 and S1—is the key to selecting the appropriate footwear.

What are the different safety classes under EN ISO 20345? A Guide from SB to S5

Decoding the Core Safety Classes

The "S" rating on safety footwear signifies its compliance with specific, tested safety features. The system is designed to be progressive, with higher numbers generally indicating more comprehensive protection.

The Foundation: SB and S1

SB (Safety Basic) represents the minimum requirement for a shoe to be classified as safety footwear. It includes a protective toecap rated for 200 joules of impact.

S1 is the next step up, designed primarily for indoor work in dry environments. In addition to the SB toecap, S1 footwear must have a fully enclosed heel, antistatic properties, oil-resistant outsoles, and energy absorption in the heel area.

Adding Hazard-Specific Protections

S1P includes all the features of S1 but adds a crucial element: midsole penetration resistance. This protects the wearer from sharp objects like nails piercing the sole of the shoe.

S2 builds upon the S1 standard by incorporating a water-resistant upper. This makes it suitable for work environments where exposure to moisture or light rain is common, but not constant submersion.

S3 is one of the most comprehensive and common ratings. It combines all the features of S2 (including a water-resistant upper) with the midsole penetration resistance of S1P. It is a robust choice for many outdoor and construction environments.

Specialized Waterproof Footwear

S4 footwear is fundamentally different in construction. It is typically a rubber boot or made from a fully moulded polymer. This construction makes the entire boot waterproof and leak-proof, but it does not include midsole penetration resistance.

S5 is the highest level of protection in this series. It has all the features of an S4 waterproof boot but also includes the midsole penetration resistance found in S1P and S3 boots, offering maximum protection in wet and hazardous environments.

Beyond the 'S' Rating: Additional Markings

While the 'S' rating covers the core requirements, additional markings indicate protection against specialized risks. These are not alternatives to the 'S' class but supplementary features.

Slip Resistance

SRA: Tested for slip resistance on a ceramic tile surface with a soap solution.
SRB: Tested for slip resistance on a steel floor with glycerol.
SRC: Footwear that passes both SRA and SRB tests.

Thermal and Cut Protection

HRO: The outsole is resistant to heat on contact.
HI: The footwear offers insulation against heat from the sole.
CI: The footwear offers insulation against cold from the sole.
CR: The upper part of the shoe is resistant to cutting.

Electrical Resistance

C: The footwear is conductive, with electrical resistance below 100 kΩ.
ESD: Electrostatic Dissipative footwear, preventing a build-up of static electrical charges.

Understanding the Trade-offs

Selecting a higher-rated boot is not always the best choice. The key is to match the protection to the actual environment without introducing unnecessary burdens.

Protection vs. Comfort

Higher levels of protection, such as those found in S3 or S5 boots, often mean a heavier and more rigid shoe due to the penetration-resistant midsole and other features. For a worker in a dry, indoor environment with no puncture risk, an S1 boot will be significantly more comfortable for all-day wear.

Breathability vs. Water Resistance

A key trade-off exists between water resistance and breathability. While S2 and S3 boots have water-resistant uppers (often leather or synthetic textiles), S4 and S5 boots are fully waterproof polymer. This makes S4/S5 boots ideal for submersion but far less breathable, which can be uncomfortable in warm conditions.

Making the Right Choice for Your Environment

Your selection should be a direct response to a risk assessment of your workplace.

If your primary focus is indoor work in a dry environment with no puncture risk: S1 provides the necessary baseline protection and comfort.
If your primary focus is preventing injuries from nails or sharp debris on the ground: S1P (for dry conditions) or S3 (for wet conditions) is essential.
If your primary focus is working outdoors or in damp conditions: S2 is the minimum, but S3 offers more complete protection if puncture risks also exist.
If your primary focus is working with large volumes of water or in constantly wet areas: Only S4 (without puncture risk) or S5 (with puncture risk) will provide adequate waterproof protection.

Ultimately, choosing the correct safety footwear is about accurately identifying the hazards you face and selecting the class designed to protect you from them.

Summary Table:

Class	Key Protections (Cumulative)	Ideal For
SB	Basic 200J toecap	Minimum safety requirement
S1	SB + Enclosed heel, antistatic, oil-resistant sole	Indoor, dry environments
S1P	S1 + Penetration-resistant midsole	Dry environments with puncture risks
S2	S1 + Water-resistant upper	Damp or outdoor environments
S3	S2 + Penetration-resistant midsole	Outdoor/wet environments with puncture risks
S4	Waterproof/leak-proof construction (e.g., rubber boot)	Constantly wet areas, no puncture risk
S5	S4 + Penetration-resistant midsole	Constantly wet areas with puncture risks

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