How Is Anti-Puncture Performance Tested in Safety Shoes?

Most buyers trust the label on the box. But I’ve spent over 20 years in this industry, and I can tell you — the label is not the test.

Anti-puncture performance in safety shoes is tested by pressing a steel nail through the midsole at a controlled speed and measuring the force required to penetrate it. EN ISO 20345 requires a minimum of 1100N¹. ASTM F2413 requires 270 lbf (approximately 1200N)². These are not the same test.

I started on the factory floor. I watched midsoles get tested one by one. I’ve seen batches pass at room temperature and fail in cold conditioning. Most buyers I talk to today still can’t tell me what force threshold their current supplier tests to. That’s a problem I want to fix — starting with what actually happens inside that shoe before it reaches your warehouse.

What Standards Define Anti-Puncture Performance in Safety Shoes?

A buyer once sent me a product spec that said only "anti-puncture required." No standard. No classification. No force value. When I asked which market the shoes were for, he wasn’t sure.

EN ISO 20345 defines two levels of puncture resistance: P1 requires the nail to be stopped at a minimum of 1100N, and P2 applies the same force threshold with tighter penetration limits. ASTM F2413 sets a minimum resistance of 270 lbf, which is roughly 1200N. These standards are not interchangeable.

That conversation — where a buyer doesn’t know which standard their market requires — happens more than you’d think. And it creates a real compliance risk. A shoe certified to one standard cannot automatically be sold as compliant in a market that requires the other.

Why the Standard Matters Before You Approve a Sample

When a buyer skips this step, they often end up approving a sample that looks right but isn’t certifiable for their target market. By the time that becomes clear, the order is already in production.

Here’s a quick breakdown of what each standard actually covers:

The force values look similar on paper, but the test method — especially what’s included in the assembly — makes a real difference to how a shoe is designed and what materials are chosen for the midsole. At Shoegan, we confirm the target standard with every buyer before we finalize a sample, because changing the midsole after sampling costs time and money that nobody wants to spend.

How Does a Nail Penetration Test Actually Work?

Most people who order anti-puncture shoes have never seen the test run. I remember the first time I watched a full test in our QC lab — the machine is quiet, the nail moves slowly, and the number on the display tells you everything.

A steel nail with a 4.5mm diameter conical tip is pressed through the midsole at a fixed speed of 10mm per minute⁴. The machine records the peak force before penetration. If the nail exits the other side before reaching the required force threshold, the sample fails.

The test looks simple. But what the machine records is only part of the story. The condition of the sample before the test — temperature, humidity, whether it’s been pre-flexed — changes the result.

What Actually Happens During the Test

The nail used in EN ISO 20345 testing has a 60-degree conical tip and is 4.5mm in diameter. It’s pressed down at a constant, controlled rate. The test machine records continuous force data, not just a pass/fail signal.

One batch of composite midsole plates we tested last winter passed at room temperature without any issue. Then we ran the cold-conditioning round — samples held at -20°C before testing — and that same batch failed⁵. The plate had stiffened, and the failure mode changed. That kind of detail does not appear on a product spec sheet.

Here’s what the test process looks like step by step:

One millimeter of variation in midsole thickness can push a product from passing to failing. That’s not a margin of error — that’s a quality control problem. At Shoegan, we test midsole thickness at multiple points across each production batch, because consistency across the midsole surface matters as much as the peak test result.

What Materials Are Used to Achieve Anti-Puncture Protection?

Three years ago, a client asked me to replace the steel midsoles in his safety shoes with Kevlar. His workers were complaining about weight. I understood why — a steel midsole alone can add around 180 grams per shoe⁶.

The three main materials used for anti-puncture midsoles are steel plates, aramid fiber (Kevlar) composites, and fiberglass composites. Each has different weight, flexibility, and chemical resistance characteristics. The right material depends on the job site conditions, not just the performance rating.

We switched that client to a 3-layer aramid fiber plate. The finished shoe came in 140 grams lighter per pair, and it still passed EN ISO 20345 P2. But I also told him the truth: aramid fiber plates can degrade faster in environments with heavy oil exposure⁷. For his specific site, we added a chemical-resistant lining over the midsole to address that risk.

Comparing the Three Main Anti-Puncture Midsole Materials

No single material is the right answer for every application. Here’s how the main options compare across the factors that matter most on a real job site:

Steel plates are the most proven and lowest cost option. They pass puncture tests reliably and handle oil and chemical exposure well. The trade-off is weight and stiffness, which affects fatigue over a long shift. Aramid fiber gives you weight savings and reasonable flexibility, but it needs additional protection in heavily contaminated environments. Fiberglass composites sit in the middle — they’re a good choice when you need something lighter than steel without the chemical sensitivity of aramid.

When a buyer asks me which material to use, my first question is always: what does the worker actually stand on every day? The answer to that question drives the material selection more than any catalog comparison does.

How Do EN ISO 20345 and ASTM F2413 Differ in Puncture Resistance Testing?

Last year I worked with a buyer who was supplying PPE to both a French construction company and a Texas oil field operator. He assumed one certified shoe could cover both markets. I had to tell him directly — it can’t.

EN ISO 20345 tests the full shoe assembly including the insole⁸, and measures nail penetration depth after the midsole is passed. ASTM F2413 tests only the midsole and measures resistance force at a threshold of 270 lbf⁹. The nail dimensions used in each standard are also different.

This buyer thought that because both standards had similar force thresholds, the certification would transfer. It doesn’t. The test method, the assembly, the nail geometry — these are all different. A shoe built to pass one standard may not pass the other without changes to the midsole construction.

Key Differences Between EN ISO 20345 and ASTM F2413 Puncture Testing

We ended up building two separate SKUs for that buyer — same upper design, different midsole configurations — to meet both certifications. That added about 12 days to his lead time. But it saved him from a compliance failure on two continents.

Here’s a direct comparison of the two standards across the points that affect midsole design:

The penetration measurement in EN ISO 20345 is the part most buyers don’t know about. It’s not enough for the nail to stop — the standard also limits how far the nail can travel into the shoe after initial penetration¹⁰. That puts more pressure on the midsole material to resist deformation, not just resist the initial force. ASTM F2413 only asks whether the force threshold was reached. These are different questions, and they lead to different midsole designs.

If you are sourcing for multiple markets, always confirm which certification is required in each market before finalizing your midsole specification. Changing it later costs time, and sometimes it means starting a new sample from scratch.

Conclusion

Anti-puncture testing is precise, standard-specific, and material-dependent. Trusting the label without knowing the test behind it is a compliance risk you don’t need to take. At Shoegan, we build safety shoes that are tested to the standard your market actually requires — EN ISO 20345, ASTM F2413, or both. Contact us at [email protected] or WhatsApp +8613008988018 to discuss your certification requirements.