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9 June 2026

Safety Boot Standards Explained: EN ISO 20345:2022 (S1–S7)

Buying safety footwear used to mean picking between "S1" and "S3." The 2022 update to EN ISO 20345 added new safety classes — including S6 and S7 — and a lot of buyers aren't sure what changed. Here's what the codes mean now.

The basics: what EN ISO 20345 covers

EN ISO 20345 is the European standard for safety footwear with toe protection (able to withstand a 200-joule impact). Every compliant boot carries a class code that tells you what protection it offers beyond the toe cap.

The classic classes

  • SB — basic: 200J toe protection only.
  • S1 — SB plus a closed heel, antistatic properties, energy absorption and fuel-oil resistance. For dry indoor environments.
  • S1P — S1 plus penetration resistance (a midsole that resists nails and sharp objects).
  • S2 — S1 plus water resistance to the upper.
  • S3 — S2 plus penetration resistance and a cleated outsole. The traditional all-rounder for construction.

What the 2022 update changed

The big change was how penetration resistance is described, reflecting newer non-metallic midsoles, plus two new top-tier classes:

  • S6 — effectively S2 plus full waterproofing (WR).
  • S7 — effectively S3 plus full waterproofing (WR).
  • New suffixes PL and PS distinguish metal (steel) penetration-resistant midsoles from non-metallic ones, tested with different nail diameters.

Many modern boots — including the Titan range we stock — are now built to S7S, meaning a fully waterproof boot with non-metallic penetration protection, ideal for wet Scottish sites.

Common additional markings

  • WR — whole boot waterproof
  • HRO — heat-resistant outsole (300°C)
  • SR — slip resistance
  • ESD — controlled static discharge (electronics/sensitive environments)
  • M — metatarsal protection

How to choose

Start with your environment: indoor and dry (S1/S1P), outdoor and wet (S3 or S7), penetration risk from nails or debris (anything with P or the new penetration codes), heat (HRO), or static-sensitive work (ESD). Then consider comfort and fit — the best boot is the one people actually wear all day.

General guidance only — always match footwear to your site's specific risk assessment.

Need PPE for your site?

We supply everything covered in this guide — with next-day delivery across Scotland and trade pricing for B2B customers.