When you handle paint thinner or detergent, you do not need a cut-resistant glove. You need one that stops chemicals, and EN ISO 374 is the certification that proves it. (Continued from Work Glove Certifications Explained.)
TL;DR
EN ISO 374 rates a glove’s chemical defense. Three things matter: how long a chemical takes to reach the skin (breakthrough levels 1 to 6, from 10 to 480 minutes), how many chemicals it holds back (Type A, B, C), and micro-organism protection (EN 374-5). The key idea is not “blocks” but “how many minutes until it gets through.”
Why chemical protection is a different world
Cuts and abrasion are visible damage. Once there is a hole, it is over. Chemicals are different. They are dangerous even with no hole.
It is like a raincoat with no holes: stand in the rain long enough and you still get wet. A chemical can pass through intact glove material molecule by molecule (permeation) and eventually reach the skin. So chemical gloves are judged not by “does it block” but by “how long does it delay.”
Three words people confuse: penetration, permeation, degradation
To understand chemical gloves, separate three words. They are completely different phenomena.
- Penetration: liquid leaking through a pinhole or a seam. A visible defect.
- Permeation: a chemical passing through intact material at the molecular level, with no hole. Invisible.
- Degradation: the glove material itself dissolving, swelling, or hardening on contact.
The core EN ISO 374 grade measures permeation, because the most dangerous failure is the one you cannot see.
Breakthrough time: how many minutes it lasts
Permeation is a race against time. The moment the chemical seeps through to the inside at a set rate (1.0 µg/cm² per minute) is called the breakthrough time, measured by the EN 16523-1 method.
The longer the breakthrough time, the higher the level, from 1 to 6.
| Level | Breakthrough time | Meaning |
|---|---|---|
| 1 | over 10 min | brief |
| 2 | over 30 min | short task |
| 3 | over 60 min | one hour |
| 4 | over 120 min | two hours |
| 5 | over 240 min | four hours |
| 6 | over 480 min | eight hours (full day) |
Do not misread it. Level 2 (30 min) does not mean “blocks for 30 minutes.” It means the chemical starts reaching the skin at around 30 minutes. You must take the glove off and swap it before then.
Type A, B, C: how many chemicals it holds back
If the breakthrough level is “how long” against one chemical, the Type is “how many.” It is set by how many of the 18 test chemicals the glove holds back to a given level.
| Type | Condition | Meaning |
|---|---|---|
| A | 6+ chemicals at level 2 (30 min+) | broadest |
| B | 3+ chemicals at level 2 (30 min+) | medium |
| C | 1+ chemical at level 1 (10 min+) | basic |
The label shows an Erlenmeyer-flask pictogram with the Type letter, plus the codes of the chemicals it resists (for example A K L).
The 18 test chemicals (A to T)
EN ISO 374 defines 18 reference chemicals and marks which ones a glove resists, by code. The list grew from 12 (2003 edition) to 18 (2016 edition); note the codes skip Q and R. Knowing the codes lets you check, from the label alone, whether your chemical is covered.
| Code | Chemical | Common use |
|---|---|---|
| A | Methanol | fuel, cleaning |
| B | Acetone | nail polish / paint remover |
| C | Acetonitrile | paints, adhesives |
| D | Dichloromethane | paint stripper |
| E | Carbon disulphide | rubber, chemical mfg |
| F | Toluene | paint, thinner |
| G | Diethylamine | epoxy, urethane |
| H | Tetrahydrofuran | adhesives, solvent |
| I | Ethyl acetate | lacquer, paint |
| J | n-Heptane | gasoline, solvent |
| K | Sodium hydroxide (caustic soda) | detergent, drain cleaner |
| L | Sulphuric acid | battery acid, metal cleaning |
| M | Nitric acid | metalwork, etching |
| N | Acetic acid (glacial) | vinegar, cleaning |
| O | Ammonium hydroxide | cleaners |
| P | Hydrogen peroxide | bleaching, disinfection |
| S | Hydrofluoric acid | glass etching, specialty metals |
| T | Formaldehyde | preservative, disinfectant, adhesive |
EN 374-5: bacteria and viruses
Separate from chemicals, micro-organism protection is covered by EN 374-5. Bacteria and fungi are checked by a leak test (EN 374-2), and virus protection by the ISO 16604 method.
The virus test pushes a phage (Phi-X174 bacteriophage) against the glove under pressure, standing in for a real virus. If it passes, the word “VIRUS” is printed below the biohazard symbol. Look for it on medical and laboratory gloves.
Lab does not equal the field: do not trust the number blindly
The grades are lab numbers, measured on a flat, still specimen at a set temperature. Real work moves the hand, warms the glove with sweat and body heat, and flexes and stretches it.
These conditions shorten breakthrough time. Chao et al. (2011) found that DMF and MEK permeate neoprene gloves in synthetic-leather work, and that simply air-drying them at room temperature over a 5-day reuse cycle did not restore new-glove protection. In short, the label grade is a ceiling, not a field guarantee.
Korea makes it mandatory: organic-chemical safety gloves
Chemical gloves get special treatment in Korea. Mechanical gloves like EN388 are a voluntary area, but organic-chemical safety gloves are subject to mandatory state certification (KCs). Along with electrical insulating gloves, they are one of only two glove types under mandatory certification.
The standard is KS K ISO 374-1, which adopts EN ISO 374-1 directly. So the test methods, Type classes, and breakthrough levels match Europe. When buying chemical gloves in Korea, look for the KCs mark.
So about that EcoGrip glove
The eco-friendly glove from the overview post carried EN388, EN407, and ANSI, but no EN ISO 374. Now the meaning is clear.
That glove is built to stop cuts and heat, not chemicals. Wear it to clean a brush with thinner or to unclog a drain with caustic soda, and despite a label full of certifications, the protection you actually need is missing. That is why you match the certification to the task.
Sources and further reading
Primary standards
– EN ISO 374-1:2016+A1:2018 — chemical protective gloves (Type and breakthrough levels)
– EN 16523-1 — permeation test method
– EN ISO 374-5:2016 — micro-organism protection / ISO 16604 — virus test
– KS K ISO 374-1 — Korean counterpart standard (KSSN)
Accredited test-house and agency references
– EN ISO 374-1:2016 chemical glove guide (HexArmor)
– Requirements for chemically protective gloves (SATRA Technology)
– Korea OSHCI protective equipment certification
– Work Glove Certifications Explained (Byeolgorae)
The breakthrough levels (10 to 480 min), Type A/B/C criteria, and the 18-chemical list were cross-checked against EN/ISO standards and accredited test-house material. The full paid standard text and some test concentrations were not read directly, so confirm against a maker’s chemical-compatibility chart and test report before real use. (Claude Opus, 2026-06-28)
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