1. What is EN 374 and Why It Matters
EN 374 is the European standard for protective gloves against dangerous chemicals and micro-organisms. It's part of the PPE Regulation (EU) 2016/425 and carries the CE marking requirement for Category III (irreversible risk) gloves.
If your workers handle solvents, acids, bases, oils, or any chemical that can cause skin damage, EN 374 is the standard you need to understand.
The current version is EN ISO 374-1:2016 (replaced EN 374-1:2003). Key changes include:
- New 3-tier classification (Type A, B, C instead of the old "micro-organism" and "chemical" labels)
- Expansion from 12 to 18 test chemicals
- Updated permeation test method (EN 16523-1)
- Clearer degradation requirements
2. The 3 Protection Types: A, B, and C
EN 374 classifies chemical gloves into 3 protection types based on how many chemicals they resist and for how long:
| Type | Minimum Chemicals | Minimum Breakthrough Time | Best For |
|---|---|---|---|
| Type A | ≥ 6 chemicals | ≥ 30 minutes (Level 2) | Heavy chemical handling, labs, chemical manufacturing |
| Type B | ≥ 3 chemicals | ≥ 30 minutes (Level 2) | Moderate chemical exposure, cleaning, maintenance |
| Type C | ≥ 1 chemical | ≥ 10 minutes (Level 1) | Light splash protection, short-duration tasks |
3. The 18 Test Chemicals and Their Codes
EN 374 tests gloves against 18 standardized chemicals, each identified by a letter code (A-T, excluding M). You'll see these letters on the glove pictogram:
| Code | Chemical Name | CAS Number | Class |
|---|---|---|---|
| A | Methanol | 67-56-1 | Primary alcohol |
| B | Acetone | 67-64-1 | Ketone |
| C | Acetonitrile | 75-05-8 | Nitrile |
| D | Dichloromethane | 75-09-2 | Chlorinated hydrocarbon |
| E | Carbon disulfide | 75-15-0 | Sulfur compound |
| F | Toluene | 108-88-3 | Aromatic hydrocarbon |
| G | Diethylamine | 109-89-7 | Amine |
| H | Tetrahydrofuran | 109-99-9 | Ether |
| I | Ethyl acetate | 141-78-6 | Ester |
| J | n-Heptane | 142-82-5 | Saturated hydrocarbon |
| K | 40% Sodium hydroxide | 1310-73-2 | Inorganic base |
| L | 96% Sulfuric acid | 7664-93-9 | Inorganic acid |
| N | 99% Nitric acid | 7697-37-2 | Inorganic acid |
| O | 65% Nitric acid | 7697-37-2 | Inorganic acid |
| P | 30% Hydrogen peroxide | 7722-84-1 | Peroxide |
| Q | 40% Hydrofluoric acid | 7664-39-3 | Inorganic acid |
| R | 37% Formaldehyde | 50-00-0 | Aldehyde |
| S | 25% Hydrofluoric acid | 7664-39-3 | Inorganic acid |
| T | 25% Ammonia | 1336-21-6 | Inorganic base |
4. Understanding Permeation Breakthrough Time
Permeation is the process by which a chemical passes through glove material at the molecular level — not through holes or visible damage. Breakthrough time is how long this takes.
EN 374 uses a 6-level performance classification:
| Level | Breakthrough Time | Protection Quality |
|---|---|---|
| 6 | > 480 minutes | Excellent |
| 5 | > 240 minutes | Very good |
| 4 | > 120 minutes | Good |
| 3 | > 60 minutes | Moderate |
| 2 | > 30 minutes | Adequate |
| 1 | > 10 minutes | Minimal |
5. Glove Material vs. Chemical Compatibility
Different glove materials offer different chemical resistance profiles. No single material protects against all chemicals:
| Material | Best Against | Poor Against | Typical Use |
|---|---|---|---|
| Nitrile (NBR) | Oils, greases, aliphatic hydrocarbons, some acids/bases | Ketones (acetone, MEK), chlorinated solvents | Automotive, metalworking, general chemical |
| Natural Latex | Water-based solutions, dilute acids/bases, alcohols | Hydrocarbons, oils, many solvents | Lab, food processing, healthcare |
| Neoprene | Acids, bases, alcohols, some solvents | Hydrocarbons, ketones | Chemical processing, petrochemical |
| Butyl | Ketones, esters, aldehydes, polar chemicals | Hydrocarbons, chlorinated solvents | Paints, coatings, pharmaceutical |
| Viton® | Aromatics, chlorinated solvents, aggressive chemicals | Ketones, low molecular weight alcohols | High-risk chemical handling |
| Laminate (Silver Shield) | Broad spectrum, virtually all chemicals | Low dexterity, expensive | Emergency response, hazmat |
6. How to Choose the Right EN 374 Glove
Step 1: Identify the Chemicals
List all chemicals your workers handle, including: chemical name and CAS number, concentration (pure vs. diluted), state (liquid, vapor, splashes), temperature.
Step 2: Check EN 374 Codes
Match your chemicals to the EN 374 test codes (A-T). Look for gloves that explicitly list those codes with Level 2 or higher breakthrough time.
Step 3: Consider Degradation
Permeation is not the only factor. Degradation — physical changes like swelling, hardening, or disintegration — can occur before permeation breakthrough. Check the degradation rating or consult the manufacturer's chemical resistance chart.
Step 4: Match Physical Requirements
- Need cut resistance? → EN 374 + EN 388 rated
- Need abrasion resistance? → Check EN 388 abrasion score
- Need dexterity? → Thinner gauge (15-18), but may sacrifice protection time
Step 5: Field Test Before Bulk Order
Lab results don't always match reality. Order samples, test in actual conditions, and get worker feedback.
Need Help Selecting Chemical Gloves?
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