If you've shopped for safety shoes, you've seen the codes: ASTM F2413, EN ISO 20345, S1, S3, I/75, C/75, EH, SRC. They look like alphabet soup, but each one tells you exactly what a shoe was tested to protect against. Here's how to read them.
ASTM F2413: the US standard
ASTM F2413 is the performance standard for protective footwear in the United States. (Canada uses its own standard, CSA Z195.) It covers shoes with a protective toe cap: every compliant shoe meets the impact and compression requirements, and any extra protection is added as a code on the label.
Example label: ASTM F2413-24 M I/75 C/75 EH PR. The M (or F) shows the shoe was tested to the men's (or women's) requirements.
| Code | Protection | Test requirement |
|---|---|---|
| I/75 | Impact | Toe cap withstands a 75 ft-lb (about 102 J) impact |
| C/75 | Compression | Toe cap withstands 2,500 lb (about 11.1 kN) |
| EH | Electrical hazard | Withstands 18,000 volts for one minute under dry conditions |
| PR | Puncture resistance | Sole resists a puncture force of 270 lb (1,200 N) |
| SD | Static dissipative | Reduces static buildup by draining it to the ground in a controlled way |
| Mt | Metatarsal | A guard protects the top of the foot from impact |
Shoes without a safety toe can't be certified to F2413. Soft-toe work shoes with protections such as EH are tested to a separate standard, ASTM F2892.
EN ISO 20345: the European and international standard
EN ISO 20345 is used across the EU and the UK and is referenced in many other markets. The current edition is EN ISO 20345:2022, but you'll still see shoes labeled to the 2011 edition.
| Class | Includes |
|---|---|
| SB | Basic safety toe: 200 J impact and 15 kN compression |
| S1 | SB plus closed heel, antistatic sole and heel energy absorption |
| S1P | S1 plus puncture resistance |
| S2 | S1 plus an upper that resists water penetration and absorption |
| S3 | S2 plus puncture resistance and a cleated outsole |
| S6 / S7 | Added in 2022: S2 or S3 plus whole-shoe water resistance |
Additional codes
| Code | Meaning |
|---|---|
| SR | 2022 edition: also passed a slip test on ceramic tile with glycerine |
| SRC | 2011 edition: passed both the SRA and SRB slip tests |
| P / PL / PS | 2022 edition: puncture resistance from a metal insert (P) or a non-metal insert tested with a 4.5 mm nail (PL) or 3 mm nail (PS) |
| WR | Whole-shoe water resistance |
| HRO | Heat-resistant outsole (tested at 300°C) |
| CI | Cold insulation |
| AN | Ankle protection |
ASTM vs EN ISO, head to head
| Feature | ASTM F2413 | EN ISO 20345 |
|---|---|---|
| Toe impact | 75 ft-lb (about 102 J) | 200 J |
| Toe compression | 2,500 lb (about 11.1 kN) | 15 kN |
| Slip resistance | Not part of F2413; tested separately | Built in, with SR (2022) or SRA, SRB and SRC (2011) markings |
| Water resistance | Not part of F2413 | S2, S3, S6, S7 and WR |
| Electrical hazard | EH code | No EH code; S1 and above are antistatic instead |
| Main markets | United States | EU, UK and many international markets |
Tip: The two standards aren't interchangeable. The tests differ, so one certification doesn't automatically satisfy the other: EN ISO 20345 tests toe caps at a higher impact energy, while ASTM F2413 offers an EH rating that EN ISO 20345 doesn't. Wear what your employer or local regulations require, and look for both marks if you work across markets.
SRC slip rating explained
Under EN ISO 20345:2011, slip resistance was marked with three codes:
| Rating | Test surface | Lubricant |
|---|---|---|
| SRA | Ceramic tile | Detergent solution |
| SRB | Steel | Glycerol |
| SRC | Both | Both; the top slip marking under the 2011 edition |
The 2022 edition simplified this. Every safety shoe must now pass the tile-and-detergent test, and SR marks shoes that also pass on tile with glycerine. Our guide to non-slip work shoes covers which grip suits which job.
SPIEZ certifications
We publish ASTM F2413, EN ISO 20345, SRC slip and UKCA declarations for our footwear. Ratings vary by model, so check the product page and our declarations of conformity for the exact markings on the shoe you're buying.
Nimbus Geneva 060
Composite toe tested to both standards
A lightweight slip-on safety sneaker. Its composite toe meets EN ISO 20345:2022 and ASTM F2413, and a Kevlar layer underfoot adds puncture resistance.
- Metal-free composite safety toe
- Kevlar puncture-resistant midsole
- Slip-resistant outsole for water, oil and detergent
- Breathable knit upper
Summit Grindelwald 371
Steel toe boot for wet sites
A mid-height boot with a steel safety toe, a puncture-resistant sole and waterproof construction. Check the product page and declaration of conformity for its exact rating.
- Steel safety toe
- Puncture-resistant sole
- Waterproof construction
- Anti-static, slip-resistant outsole
Which standard do you need?
- US construction: ASTM F2413 I/75 C/75, plus PR and EH where your site requires them.
- European and UK construction: EN ISO 20345 S3 (or S7 for very wet sites), with SR or SRC slip resistance.
- Food service and healthcare: slip-resistant work shoes tested on wet and oily floors; a safety toe only if your workplace requires one.
- Working across markets: look for both ASTM F2413 and EN ISO 20345 on the label.
Choosing for a job site? See how to choose safety shoes for construction.
Frequently asked questions
What does ASTM F2413 mean on safety shoes?
It's the US performance standard for footwear with a protective toe cap. A shoe labeled F2413 has been tested to meet its impact and compression requirements, plus any extra codes on the label, such as EH or PR.
What is the difference between S1, S2 and S3 safety shoes?
S1 provides a safety toe, closed heel, antistatic sole and heel energy absorption. S2 adds a water-resistant upper. S3 adds puncture resistance and a cleated outsole, and is the usual choice for construction.
What does SRC mean on safety shoes?
SRC is the top slip-resistance marking under EN ISO 20345:2011. It means the shoe passed both the SRA test (ceramic tile with detergent) and the SRB test (steel with glycerol). The 2022 edition replaced the SRA, SRB and SRC markings with SR.
Is EN ISO 20345 the same as ASTM F2413?
No, but they serve the same purpose. EN ISO 20345 is the European and international standard; ASTM F2413 is the US standard. EN ISO 20345 tests toe caps at a higher impact energy (200 J vs about 102 J), while ASTM F2413 includes an EH rating that EN ISO 20345 doesn't.
Know the code, then pick the shoe.
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