EN 343 is the European standard for protective clothing against rain. The label shows two numbers separated by a dash (e.g., EN 343:2019 3-3). The first number rates water penetration resistance (1-4 scale, 4 is highest). The second number rates breathability (1-4 scale, 4 is highest). A 4-1 rating means excellent rain protection but poor breathability — the wearer sweats inside the jacket. For workers doing physical labor outdoors, specify minimum 3-3. For standing guard or light duty, 4-1 or 4-2 is acceptable. Always verify with a lab test report, not just the label claim.
Two numbers on a rain jacket label decide whether your crew stays dry — or sweats inside a plastic bag.
Most buyers never read them. They see "EN 343 certified" and move on. Then the complaints come in: "The jacket leaks" (it doesn't — it's sweat), or "The workers feel clammy" (they are — trapped vapor). The problem is not the standard. The problem is that EN 343 is a two-axis rating, and most spec sheets only look at the first number.
Here is what the label actually means, and how to spec it correctly.
The Two Numbers
First number: Water Penetration Resistance (1-4)
| Class | What it withstands | Real-world equivalent |
| ------- | ------------------- | ---------------------- | ||||
| 1 | Light drizzle | Walking to the car | ||||
| 2 | Moderate rain | Standing guard, light outdoor work | ||||
| 3 | Heavy rain | Active construction, roadwork | ||||
| 4 | Driving rain under pressure | Marine work, storm conditions | Test method: hydrostatic head (mm of water column the fabric supports before leaking). Class 4 requires ≥ 13,000 Pa after pretreatment. Second number: Breathability (1-4) | Class | Water vapor resistance (Ret) | Comfort level |
| ------- | ------------------------------ | ------------- | ||||
| 1 | Ret > 40 m²·Pa/W | Sauna suit | ||||
| 2 | 25 < Ret ≤ 40 | Tolerable for short tasks | ||||
| 3 | 15 < Ret ≤ 25 | Acceptable for active work |
Test method: ISO 11092 sweating guarded hotplate. Lower Ret = more breathable.
The Trap: 4-1 Is Not "Best"
A buyer sees "EN 343 Class 4" and thinks maximum protection. They order 4-1 jackets for a road crew. The jackets keep the rain out perfectly — and the workers are soaked in sweat within two hours. The crew unzips the jackets to vent. Now they are wet from rain anyway, plus cold.
The 4-1 rating is not a failure. It is a tool for a specific job: short-duration, low-exertion, high-rainfall exposure. Think security guard at a fixed post, or a photographer at an outdoor event.
For active outdoor work, 3-3 is the practical minimum. The first 3 handles heavy rain; the second 3 lets sweat escape during physical labor. For high-exertion tasks (roofing, logging, emergency response), specify 3-4 or 4-4.
The 2019 Update: Durability After Washing
The 2019 revision added optional pretreatment tests. A jacket that passes EN 343 new may fail after five industrial washes if the waterproof coating degrades.
Look for suffixes on the label:
- W = tested after washing
- D = tested after dry cleaning
If your crew launders their rainwear weekly, specify "EN 343:2019 3-3 W" and demand the wash-cycle test report. The number of washes matters: "5W" means tested after 5 washes, "25W" after 25.
How to Verify (Not Trust)
Labels lie. Certificates are photocopied. The only proof is a lab test report from an accredited laboratory (SGS, TÜV, Intertek, or a national lab with ISO 17025 accreditation).
Ask for:
A real factory has these reports on file. A trader emails you a PDF with someone else's company name on it.
Spec Sheet Language
Bad spec: "EN 343 certified rain jacket"
Good spec: "EN 343:2019 Class 3-3 W25 (water penetration ≥ 8,000 Pa after 25 washes; breathability Ret ≤ 25 m²·Pa/W after 25 washes). Fully taped seams. Fabric: 300D Oxford PU microporous coating. Test reports required from ISO 17025-accredited lab."
The first tells the supplier you don't know what you're buying. The second tells them you do.
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Denny Lin is the export manager at a Fujian workwear factory. We test every batch of EN 343 fabric in-house and send samples to SGS for verification. Ask for our current 3-3 W25 test report — it is one email away.
Watch: 3 Desk Checks in 80 Seconds
The 60-second version of checks #1, #4 and #3 from this article — on our YouTube channel.
Frequently Asked Questions
What does EN 343:2019 4-1 mean?+
The first number (4) is water penetration resistance — the highest level, withstanding heavy rain under pressure. The second number (1) is breathability — the lowest level, meaning sweat vapor cannot escape. A 4-1 jacket is suitable for short-duration stationary work in heavy rain, but will cause overheating and internal condensation during physical activity.
What is the best EN 343 rating for construction workers?+
Minimum 3-3 for active construction work. The first 3 ensures protection against moderate to heavy rain; the second 3 ensures adequate breathability for physical labor. For high-exertion tasks (roofing, roadwork), specify 3-4 or 4-4. Never go below 2-2 for any outdoor work — the wearer will be wet from sweat if not from rain.
Can a jacket be EN 343 4-4?+
Yes, but 4-4 is rare and expensive. It requires a waterproof-breathable membrane (e.g., PU microporous or PTFE laminate) with fully taped seams. Most budget rainwear is 2-1 or 3-1. If a supplier claims 4-4 at a low price, demand the lab test report — the rating is likely inflated.
Does EN 343 cover durability after washing?+
Yes. The 2019 version includes optional tests for water penetration and breathability after pretreatment (washing and dry cleaning). Look for the suffix "W" (washable) or "D" (dry cleanable) on the label. A jacket that passes EN 343 initially but fails after 5 washes is non-compliant for ongoing use.
About Fujian Rising Outdoor Products
BSCI, SMETA and SCAN-audited manufacturer of outdoor workwear & PPE since 2012. 865 workers, 250 computerized sewing machines. Serving brands in the EU, US, Canada and Australia.
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