Standard explainer · EN ISO 20345
The letters on a safety boot label are a stacking system: each code is the previous one plus something. Once you see the stack, the whole standard reads in about two minutes.
How the codes stack
EN ISO 20345 starts every class from the same base: a toe cap rated for a 200-joule impact and 15 kN compression. That base alone is SB ("safety basic"). From there the numbered codes stack features:
So "which code?" is really "which features does the ground demand?" — the table below puts the whole stack side by side.
The full table
✓ = required by the class. Every class includes the 200 J toe cap.
| Code | Antistatic + heel | Water-resistant upper | Puncture midsole | Cleated sole | Waterproof (WR) | Typical use |
|---|---|---|---|---|---|---|
| SB | — | — | — | — | — | Bare-minimum indoor |
| S1 | ✓ | — | — | — | — | Dry indoor, warehouse |
| S1P | ✓ | — | ✓ | — | — | Warehouse with fixings underfoot |
| S2 | ✓ | ✓ | — | — | — | Food production, wet-clean floors |
| S3 | ✓ | ✓ | ✓ | ✓ | — | General construction — the site default |
| S4 | ✓ | polymer boot | — | — | inherent | Wet hygiene areas (wellington) |
| S5 | ✓ | polymer boot | ✓ | ✓ | inherent | Groundworks, agriculture (wellington) |
| S6 | ✓ | ✓ | — | — | ✓ | Wet outdoor work, lighter risk underfoot |
| S7 | ✓ | ✓ | ✓ | ✓ | ✓ | Wet sites with puncture risk — S3 for winter |
2022 changes
Boots certified to the older 2011 edition are still legally sold and worn, so both label styles are in circulation. The practical changes to know:
Add-on letters
Optional marks appear after the class — a label might read "S3L HRO CI SR".
| Mark | Means | Worth having when |
|---|---|---|
| SR | Passed the enhanced slip test | Smooth wet floors — kitchens, hygiene, forecourts |
| HRO | Outsole survives 300 °C contact | Hot works, asphalt, foundries |
| CI / HI | Cold / heat insulated sole | Cold stores; hot process floors |
| WR | Whole-footwear water resistance | Outdoor work — this is the mark that makes S6/S7 |
| M | Metatarsal (top-of-foot) protection | Heavy handling where drops land above the toes |
| AN | Ankle protection | Uneven ground, groundworks |
| SC / LG | Scuff cap / ladder grip | Kneeling trades; ladder-heavy work |
| ESD | Electrostatic-dissipative (separate standard) | Electronics assembly, ATEX-adjacent work |
Questions
S1P is an S1 boot (toe cap, antistatic, energy-absorbing heel, closed seat) plus a puncture-resistant midsole. Since the 2022 standard the midsole letter can also appear as PL or PS, which mark non-metal inserts tested against large and small nails respectively.
Both have a toe cap, midsole, water-resistant upper and cleated sole. S7 adds certified whole-boot water resistance (the WR test) — an S3 resists water soaking through the upper for a period; an S7 is tested as a waterproof boot. For regular wet outdoor work, S7 is the closer match.
Yes — the 2022 revision of EN ISO 20345 introduced them. S6 is S2 plus whole-boot waterproofing, S7 is S3 plus the same. Before 2022, waterproof boots were sold as S2 WR or S3 WR; those older labels remain valid on existing certified stock.
Yes, if they carry an EN ISO 20345 code — a safety trainer marked S1P has exactly the same toe cap and midsole performance as an S1P boot. What a trainer gives up is ankle coverage and, usually, the water resistance and cleated sole of an S3.
EN ISO 20345 boots, shoes and safety trainers from stock — S1P and S3 always available, with trade-account ordering for teams.