EN ISO 20345 classes: what SB, S1, S1P, S2 and S3 mean

The baseline: SB

The shared minimum of all safety footwear is a toecap resisting a 200 J impact and a 15 kN compression, plus the basic structural, comfort and slip-resistance requirements. That is class SB (Safety Basic).

The building classes

Class	What it adds to the previous one
S1	closed seat region, antistatic behaviour, energy-absorbing heel
S1P	S1 + perforation-resistant insert
S2	S1 + upper resistance to water penetration and absorption
S3	S2 + perforation resistance + cleated outsole
S4 / S5	all-moulded (rubber/polymer) boots at S1 and S3 content

What the 2022 edition brought

EN ISO 20345:2022 introduced two new classes: S6 (S2 + whole-footwear waterproofness) and S7 (S3 + whole-footwear waterproofness). Upper water resistance (WRU) and whole-footwear waterproofness (WR) are distinct concepts — one concerns the material, the other the finished shoe. The perforation-resistance marking was also refined by test-nail diameter (P, PL, PS).

Additional markings

Beyond its class, footwear may carry further tested properties: for example HRO (outsole resistant to contact heat), HI/CI (heat/cold insulation), ESD (electrostatic dissipation — separate standard), FO (fuel-resistant outsole). Behind every marking stands a performed test.

Why it matters in practice

In procurement specifications and tenders, the class marking is the common language. For manufacturers and importers the question is whether the product delivers every element of the marked class, demonstrated by measurement — because the marking is not a declaration, it is a summary of test results.