Compliance Tool · Free
Safety Footwear Label Decoder
Paste any ASTM F2413 or EN ISO 20345 marking and instantly see what every code means — from S1 through S7, SRC to HRO, and I/75 to EH.
Paste the label
Decoded 5 codes
- S3
Safety Class 3
EN ISO 20345 class
All S2 properties plus penetration resistance (P) and cleated outsole. The most common spec for general construction.
- HRO
Heat resistant outsole
EN additional code
Outsole resists contact heat of 300 °C for 60 s without melting.
- CI
Cold insulation of sole
EN additional code
Sole insulates against contact cold down to −17 °C for 30 min.
- M
Metatarsal protection
EN additional code
Additional top-of-foot impact guard (≥ 100 J).
- SRC
Slip resistance — SRA + SRB
Slip resistance
Passes both tests. Pre-2022 gold standard for slip resistance.
ASTM F2413 vs EN ISO 20345
The two dominant safety-footwear standards cover similar protections with different test methods and code formats. Boots certified to both standards are acceptable in almost every global workplace.
| Property | EN ISO 20345 (EU) | ASTM F2413 (US) |
|---|---|---|
| Governing body | CEN (European Committee for Standardization) | ASTM International |
| Toe impact | 200 J (all classes) | 75 ft·lb (I/75) or 50 ft·lb (I/50) |
| Toe compression | 15 kN (all classes) | 2,500 lbf (C/75) or 1,750 lbf (C/50) |
| Puncture resistance | Optional — marked P, PS or PL | Optional — marked PR |
| Metatarsal | Optional — marked M | Optional — marked Mt/75 |
| Electrical hazard | Antistatic (A) is standard; full insulation not common | EH — secondary insulation (18 kV) |
| Slip resistance | SR mandatory (2022); legacy SRA/SRB/SRC widespread | Not mandated — some brands self-certify |
| Water resistance | Optional — WRU (upper) or WR (whole boot) | Not part of F2413 — covered by voluntary specs |
EN ISO 20345 protection classes
Every EN-certified safety boot is marked with one class code (SB, S1, S1P, S1PS, S2, S3, S3S, S4, S5, S6 or S7). The class defines the baseline protection — add-on codes like HRO, CI, M extend it.
| Class | Name | What it covers |
|---|---|---|
| SB | Safety Basic | 200 J toe impact + 15 kN compression. Minimum safety footwear under EN ISO 20345 — no other properties required. |
| S1 | Safety Class 1 | SB plus: closed seat region, antistatic (A), energy absorption in heel (E), fuel oil resistance (FO). For dry indoor work. |
| S1P | Safety Class 1 with Penetration resistance | All S1 features plus midsole penetration resistance (P). Common in light construction and maintenance. |
| S1PS | S1P with textile penetration (2022) | EN ISO 20345:2022 revision — S1P with PS textile anti-penetration midsole (lighter, more flexible than steel). |
| S2 | Safety Class 2 | All S1 properties plus water penetration and absorption resistance of the upper (WRU). For wet indoor/outdoor environments. |
| S3 | Safety Class 3 | All S2 properties plus penetration resistance (P) and cleated outsole. The most common spec for general construction. |
| S3S | S3 with textile penetration (2022) | EN ISO 20345:2022 — S3 with PS textile anti-penetration midsole. Lighter alternative to steel midsole. |
| S4 | Safety Class 4 (all-rubber/polymeric) | Fully moulded boots (rubber/PVC). Antistatic, energy absorption, fuel oil resistance. Typical for agriculture, food, fishing. |
| S5 | Safety Class 5 | All S4 properties plus penetration resistance (P) and cleated outsole. Wet, muddy, sharp-debris environments. |
| S6 | Safety Class 6 (2022) | New in EN ISO 20345:2022 — S2 specification with fully waterproof boot (WR). Rubber-like protection in a leather upper. |
| S7 | Safety Class 7 (2022) | New in EN ISO 20345:2022 — S3 specification with fully waterproof boot (WR). Highest leather-boot spec. |
EN additional requirement codes
Add-on codes extend the baseline class — for example, an S3 HRO CI boot adds heat-resistant outsole (HRO) and cold insulation (CI) to the S3 specification.
| Code | Meaning | Test requirement |
|---|---|---|
| P | Penetration resistance (steel) | Steel midsole resists 1,100 N nail penetration. |
| PS | Penetration resistance (textile) | Textile/composite midsole resists 1,100 N (new 2022 test). |
| PL | Penetration resistance with large test nail | 1,100 N with 4.5 mm nail — 2022 replacement for metallic midsole. |
| A | Antistatic | Electrical resistance between 100 kΩ and 1 GΩ — dissipates static without full insulation. |
| E | Energy absorption (heel) | Heel absorbs ≥ 20 J of impact. Reduces fatigue on hard floors. |
| FO | Fuel oil resistance | Outsole resists degradation from fuel oils and hydrocarbons. |
| WR | Whole boot water resistance | Entire boot waterproof — tested by walking through a water trough. |
| WRU | Water resistant upper | Upper resists water penetration/absorption for ≥ 60 min (not fully waterproof). |
| HI | Heat insulation of sole | Sole insulates against contact heat up to 150 °C for 30 min. |
| CI | Cold insulation of sole | Sole insulates against contact cold down to −17 °C for 30 min. |
| HRO | Heat resistant outsole | Outsole resists contact heat of 300 °C for 60 s without melting. |
| M | Metatarsal protection | Additional top-of-foot impact guard (≥ 100 J). |
| AN | Ankle protection | Lateral ankle impact resistance. |
| CR | Cut resistance (upper) | Upper resists cut-through — protects against glass, metal shards. |
| ESD | Electrostatic discharge | Resistance 100 kΩ–100 MΩ — tighter range than A, for electronics assembly. |
| SC | Scuff cap abrasion | 2022 test — toe cap abrasion resistance (replaces unofficial "SRC+" marking). |
| LG | Ladder grip | New 2022 — outsole tread optimised for ladder rungs. |
| FP | Metatarsal flexibility (internal) | Internal flexible metatarsal guard. |
Slip resistance codes
EN ISO 20345:2022 replaced the legacy SRA/SRB/SRC system with a single mandatory SR test, but you will still see SRA, SRB and SRC on boots manufactured under the previous revision.
| Code | Surface / contaminant |
|---|---|
| SRA | Slip resistance — ceramic + SLS. Tested on ceramic tile with sodium lauryl sulphate solution. |
| SRB | Slip resistance — steel + glycerol. Tested on steel floor with glycerol. More aggressive than SRA. |
| SRC | Slip resistance — SRA + SRB. Passes both tests. Pre-2022 gold standard for slip resistance. |
| SR | Slip resistance (2022). Mandatory in EN ISO 20345:2022 — ceramic + glycerol, stricter than SRB. |
ASTM F2413 section codes
ASTM-certified boots carry a four-line label: standard reference (F2413-18), gender and ASTM class, impact/compression rating (I/75, C/75) and any additional protections (PR, EH, SD, CD, Mt/75, DI).
| Code | Meaning | Detail |
|---|---|---|
| ASTM F2413-18 | US safety footwear standard | Current revision. Footwear must also be marked with section numbers identifying which protections it provides. |
| I/75 | Impact resistance 75 ft·lb | 75 ft·lb (≈ 101 J) toe impact — primary ASTM toe protection rating. |
| I/50 | Impact resistance 50 ft·lb | 50 ft·lb toe impact — lower tier, less common today. |
| C/75 | Compression resistance 2500 lbf | 2,500 lbf (≈ 11.1 kN) toe compression — pairs with I/75. |
| C/50 | Compression resistance 1750 lbf | 1,750 lbf compression — pairs with I/50. |
| Mt/75 | Metatarsal 75 ft·lb | Top-of-foot impact resistance equivalent to I/75. |
| PR | Puncture resistance | Midsole resists ≥ 270 lbf puncture — equivalent to EN "P". |
| EH | Electrical hazard | Secondary insulation — withstands 18 kV for 60 s at ≤ 1.0 mA leakage. NOT primary insulation. |
| SD | Static dissipative | Resistance 10⁶–10⁸ Ω. For electronics and explosive-atmosphere work. |
| CD | Conductive | Resistance ≤ 500 kΩ. Dissipates static for explosive-atmosphere work. |
| DI | Dielectric insulation | Primary electrical insulation to ASTM F2412 — rare, specialty line work. |
| PR/SRC | Puncture + Slip (combined label) | Example combined marking seen on the tongue label. |
How to read a safety boot label
Every certified safety boot carries its marking on the tongue, sidewall or inside-collar label. Here is how to read both formats at a glance.
EN ISO 20345 example
CE 0493 EN ISO 20345:2022 S3 SRC HRO CI Size 43
- S3 — water-resistant upper, cleated outsole, penetration-resistant midsole
- SRC — passes both ceramic + steel slip tests
- HRO — outsole resists 300 °C contact heat
- CI — sole insulates against cold to −17 °C
ASTM F2413 example
ASTM F2413-18 M I/75 C/75 EH PR Size 10 W
- M — men's sizing
- I/75 C/75 — 75 ft·lb impact + 2,500 lbf compression
- EH — electrical hazard (18 kV secondary insulation)
- PR — puncture-resistant midsole
Frequently asked questions
What does S3 SRC HRO mean on a safety boot?
S3 is an EN ISO 20345 class meaning the boot has a steel toe (200 J), steel midsole penetration resistance, water-resistant upper, cleated outsole, antistatic and energy-absorbing heel. SRC means the outsole passes both ceramic-tile (SRA) and steel-floor glycerol (SRB) slip tests. HRO means the outsole is heat-resistant up to 300 °C for 60 seconds.
What is the difference between S1, S2 and S3?
S1 boots have steel toe, closed heel, antistatic, energy absorption and fuel oil resistance — best for dry indoor work. S2 adds water-resistant upper for wet environments. S3 adds both penetration resistance (steel midsole) and a cleated outsole — the common spec for general construction.
What is the difference between ASTM F2413 and EN ISO 20345?
ASTM F2413 is the US standard, EN ISO 20345 is the European standard. Both cover similar protections but use different test methods and code formats. EN uses class letters (S1–S7) with protection add-ons (HRO, CI, etc.). ASTM uses section-number markings (I/75, C/75, PR, EH, M). Some brands certify boots to both standards.
What does EH stand for on work boots?
EH stands for Electrical Hazard. An ASTM F2413-marked EH boot provides secondary insulation — it withstands 18,000 volts for 60 seconds at ≤ 1 mA leakage when new, dry and undamaged. It is NOT primary electrical insulation for live-line work; that requires ASTM F2412 dielectric (DI) boots.
What is the new EN ISO 20345:2022 and what changed?
The 2022 revision introduced two new classes — S6 (waterproof S2) and S7 (waterproof S3) — replaced SRA/SRB/SRC with a single mandatory SR slip test, added PS/PL codes for textile midsole penetration resistance, and added ladder-grip (LG) and scuff-cap (SC) markings. Existing S3 SRC boots are still legal and widely sold.
How do I know if a safety boot is properly certified?
Look for three things on the tongue or inside label: (1) the standard reference (EN ISO 20345:2022 or ASTM F2413-18), (2) the classification codes (e.g. S3 SRC HRO or I/75 C/75 PR), and (3) a CE mark (EU), UKCA mark (UK) or ANSI/ASTM notified body identifier. Boots without these markings are not certified safety footwear.
Is SRC or SR better for slip resistance?
SR (from EN ISO 20345:2022) is stricter — it uses a ceramic tile + glycerol combination, which is more aggressive than the old SRA (ceramic + soap). SRC (SRA + SRB) was the pre-2022 top slip rating and remains excellent. Boots marked SR or SRC both offer top-tier slip resistance.
What does P, PS and PL mean for puncture resistance?
All three certify a midsole that resists 1,100 N penetration. P uses a steel midsole tested with a 4.5 mm nail. PS uses a textile/composite midsole tested with a smaller 3 mm nail (more flexible, lighter). PL uses a textile midsole tested with the larger 4.5 mm nail — the toughest textile option.
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