Quality guide

Safety Shoe Standards: EN ISO 20345 Explained

By DOING SHOES · Reviewed by our product team · Last updated 2026-07-06T00:00:00.000Z · 10 min read

A buyer's guide to safety footwear standards — EN ISO 20345 (SB, S1, S1P, S2, S3, S6, S7) and US ASTM F2413 decoded, what each code means, what changed in the 2021 revision, and how to spec the right protection.

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“Safety shoes” is not one thing. A steel-toe trainer for a warehouse and a puncture-resistant, water-resistant boot for a construction site are both “safety footwear” — but they are certified to different levels, marked with different codes, and legal in different jobs. If you import or sell work footwear, reading those codes correctly is the difference between shipping compliant product and shipping a liability.

This guide decodes the two standards that matter for most buyers — EN ISO 20345 (Europe and much of the world) and ASTM F2413 (United States) — explains every marking, and covers what changed in the 2021 revision that a lot of old spec sheets still get wrong.

First, three standards people mix up

Under the European system, the toe-cap energy rating decides which standard applies:

Standard	Footwear type	Toe cap
EN ISO 20345	Safety footwear	200 J impact protection
EN ISO 20346	Protective footwear	100 J impact protection
EN ISO 20347	Occupational footwear	No toe cap (comfort/slip/ESD only)

Most work footwear buyers want EN ISO 20345 — the 200 J safety class. The others exist, and mislabelling one as another is a common (and serious) spec error.

EN ISO 20345 — the graded categories

Everything starts from SB (the basic requirement: the 200 J toe cap plus baseline slip resistance). The “S” categories bundle SB with common combinations of extra properties, so you can specify one code instead of a long list:

Category	Toe cap	Adds on top of SB
SB	200 J	Basic requirement + baseline slip resistance
S1	200 J	Closed seat region · A (antistatic) · E (energy absorption at heel) · FO (fuel-oil-resistant outsole)
S1P	200 J	S1 + P (penetration/puncture resistance, metal midsole)
S2	200 J	S1 + WPA (water penetration & absorption of the upper)
S3	200 J	S2 + P + cleated (profiled) outsole
S6	200 J	S2 + WR (whole-shoe water resistance)
S7	200 J	S3 + WR (whole-shoe water resistance)
S4 / S5	200 J	Moulded all-rubber or all-polymer footwear (S5 adds P + cleated outsole)

How to read it fast: higher number ≈ more protection. S1 is a dry-indoor safety shoe; S2 adds a water-resistant upper; S3 is the workhorse construction/outdoor spec (puncture-resistant, cleated, water-resistant upper); S6/S7 are the new fully water-resistant grades.

The property codes (the letters after the S)

Beyond the bundled categories, individual properties are marked with their own codes. These are the ones on real spec sheets:

Code	Meaning
P	Penetration resistance — steel midsole (4.5 mm nail)
PL	Penetration resistance — non-metallic, large 4.5 mm nail
PS	Penetration resistance — non-metallic, small 3.0 mm nail
A	Antistatic
C	Conductive
E	Energy absorption of the seat (heel) region
FO	Fuel-oil resistance of the outsole
WPA	Water penetration & absorption of the upper (was “WRU” pre-2021)
WR	Water resistance of the whole shoe
HI / CI	Heat / cold insulation of the sole complex
HRO	Outsole resistance to hot contact (300 °C)
M	Metatarsal protection
AN	Ankle protection
SC	Scuff cap abrasion resistance (new in 2021)
LG	Ladder grip (new in 2021)

What the 2021 revision changed

A lot of catalogues still quote the 2011 standard. The EN ISO 20345:2021 update matters because it changed how you compare shoes:

• Slip resistance is now a mandatory baseline for every safety shoe. The old SRA / SRB / SRC ratings were withdrawn — you no longer pick a slip rating, because all compliant footwear must pass the baseline test. An optional “SR” mark now flags enhanced slip performance tested against extra conditions.
• Non-metallic penetration codes PL and PS were added next to the steel-midsole P, so composite puncture protection is stated precisely (nail size matters — 3.0 mm nails are harder to stop than 4.5 mm).
• Two new markings — SC (scuff cap) and LG (ladder grip) — for scuff-prone and ladder-heavy work.
• New categories S6 and S7 give a whole-shoe water-resistant option (S2+WR and S3+WR).

If a supplier is still quoting “SRC” as a selling point on a 2021-certified shoe, that is a flag their paperwork has not been updated.

The US system — ASTM F2413

North American buyers work to ASTM F2413 instead. It is marked as a short block, e.g. ASTM F2413-18 M I/75 C/75 EH:

Marking	Meaning
M / F	Fitted for male / female
I/75	Impact resistance, 75 ft-lbf
C/75	Compression resistance, 2,500 lbf
EH	Electrical hazard resistance
SD	Static dissipative
CD	Conductive
PR	Puncture resistance
Mt	Metatarsal protection
DI	Dielectric insulation

The key point for sourcing: EN ISO 20345 and ASTM F2413 are not interchangeable. They use different impact energies, different test methods and different marking. A shoe built and certified for the EU is not automatically US-compliant, and vice-versa — you build to the standard your destination market enforces.

Steel toe vs composite toe

Both can meet the 200 J / I-75 toe requirement — the choice is about everything around the protection:

	Steel toe	Composite toe (e.g. TPU, fibreglass)
Protection level	Meets standard	Meets standard
Weight	Heavier	Lighter
Thermal	Conducts heat/cold	Insulates better
Metal detectors / airports	Sets them off	Non-metallic
Typical use	General industry, lowest cost	Cold, electrical, security-screened work

The same logic applies to the puncture-resistant midsole: a steel midsole (P) is proven and cheap; a non-metallic midsole (PL/PS) is lighter, more flexible and covers more of the sole, but the nail size in the code matters.

How to spec safety footwear as a buyer

Work backwards from the hazard, not the price:

1. Impact/crush risk? → 200 J toe cap (EN ISO 20345) or I/75 C/75 (ASTM). This is the baseline “safety” line.
2. Sharp objects underfoot (nails, swarf)? → penetration resistance P / PL / PS.
3. Wet environment? → S2 (water-resistant upper) or S3 / S6 / S7 / WR (more water protection).
4. Slip risk? → all 2021 footwear passes baseline slip; add SR for enhanced.
5. Static, electrical or explosive-atmosphere work? → A (antistatic) / EH / SD as the job requires.
6. Cold, heat, ladders, scuffing? → CI / HI / HRO / LG / SC.

Then confirm the destination market’s standard (EN vs ASTM) and ask for the test report from an accredited lab — a code on a box is a claim; the lab report is the evidence.

How we build safety footwear

DOING develops and manufactures safety and workwear footwear built to the standard your market specifies — EN ISO 20345 or ASTM F2413 — with steel or composite toe caps, steel or non-metallic penetration-resistant midsoles, and slip-, oil- and puncture-resistant outsoles. The construction is confirmed on the finished shoe through our in-house physical-testing programme (whole-shoe bond strength, outsole flex and abrasion, cold-flex and more — see testing standards), and we provide accredited third-party lab reports on request.

Two honest notes buyers should know:

• Certification is separate from capability. CE marking to EN ISO 20345 requires EU type-examination by a notified body; ASTM compliance requires testing to F2413. We build to the standard and support the testing and certification process for your styles — we do not “self-issue” a CE certificate, and you should be wary of any factory that claims to.
• Materials compliance still applies. Safety footwear must also meet chemical restrictions for its market (REACH/RSL) — see our chemical compliance and certifications pages, and the EN ISO 20345 glossary entry for a quick definition.

Speccing a safety or workwear range? Tell us the hazard, the market and the standard and we will build to the exact category and codes your buyers require — and back it with lab reports, not just a mark on the box.