EN 374-1 is the standard for gloves designed for protection against dangerous chemicals and EN 374-5 is the standard for gloves designed for protection against micro-organisms. These standards cover permeation and degradation resistance against liquid chemicals, and penetration resistance against micro-organisms, with further optional testing for viral penetration resistance.
Permeation resistance: three specimens taken from the palms of three different gloves are tested in accordance with EN 16523-1 for permeation resistance (defined as the time for a permeation rate of 1 µg/cm²/min to be reached, or the ‘breakthrough time’) against any of 18 specified chemicals (each chemical in this list has an associated code letter, from A-T, excluding Q and R – see table below). Various analytical methods may be used depending on the chemical, including gas chromatography, conductimetry, and Fourier-transform infrared spectroscopy.
The breakthrough time for all three specimens must fall within ± 20% of the mean result. If after a repeated test the results for each of the three specimens still do not all fall within 20% of the mean, the glove is considered to fail due to inhomogeneity.
If the glove is over 400 mm in length the cuff must also be tested, and the performance level is based on the lowest test result obtained by either palm or cuff.
| Code letter | Chemical | CAS number | Class |
| A | Methanol | 67-56-1 | Primary alcohol |
| B | Acetone | 67-64-1 | Ketone |
| C | Acetonitrile | 75-05-8 | Nitrile compound |
| D | Dichloromethane | 75-09-2 | Chlorinated hydrocarbon |
| E | Carbon disulphide | 75-15-0 | Sulphur containing organic compound |
| F | Toluene | 108-88-3 | Aromatic hydrocarbon |
| G | Diethylamine | 109-89-7 | Amine |
| H | Tetrahydrofuran | 109-99-9 | Heterocyclic and ether compound |
| I | Ethyl acetate | 141-78-6 | Ester |
| J | n-Heptane | 142-82-5 | Saturated hydrocarbon |
| K | Sodium hydroxide (40%) | 1310-73-2 | Inorganic base |
| L | Sulphuric acid (96%) | 7664-93-9 | Inorganic mineral acid, oxidising |
| M | Nitric acid (65%) | 7697-37-2 | Inorganic mineral acid, oxidising |
| N | Acetic acid (99%) | 64-19-7 | Organic acid |
| O | Ammonium hydroxide (25%) | 1336-21-6 | Organic base |
| P | Hydrogen peroxide (30%) | 7722-84-1 | Peroxide |
| S | Hydrofluoric acid (40%) | 7664-39-3 | Inorganic mineral acid |
| T | Formaldehyde (37%) | 50-00-0 | Aldehyde |
Note: other chemicals may be tested, but gloves may only be certified against the 18 chemicals listed above. These chemicals are intended to be representative of major chemical classes, and may provide an indication of how the glove will perform against similar chemicals. This standard does not cover protection from solid or gaseous chemicals, or mixtures of chemicals.
Permeation performance levels are assigned according to the requirements in the below table, and are based on the specimen with the lowest breakthrough time:
| Performance level | 1 | 2 | 3 | 4 | 5 | 6 |
| Breakthrough time (minutes) | > 10 | > 30 | > 60 | > 120 | > 240 | > 480 |
There are three categories of chemical resistant gloves: Type A, Type B, and Type C, determined by the number of chemicals tested:
Type A: the glove must achieve a minimum of performance level 2 permeation resistance against at least 6 chemicals. Code letters for the tested chemicals are shown under the pictogram.
Type B: the glove must achieve a minimum of performance level 2 permeation resistance against at least 3 chemicals. Code letters for the tested chemicals are shown under the pictogram.
Type C: the glove must achieve a minimum of performance level 1 permeation resistance against at least 1 chemical. No code letters are shown under the pictogram.
Degradation resistance: all gloves claiming permeation resistance to specific chemicals must also have a degradation test carried out according to EN 374-4 for the same chemicals. This test involves puncturing glove specimens with a stylus and measuring the peak force before and after 1 hour contact with the challenge chemical. There are no performance levels or requirements for this test – the results may be seen as an indication of the ability of the glove to maintain its barrier properties after contact with the test chemical.
Penetration resistance (bacteria, fungi, and viruses): EN 374-1 specifies that all gloves claiming chemical resistance must also meet EN 374-2 air and water penetration resistance testing. These tests involve filling one glove of each size (or at least four gloves if the glove is sold in fewer sizes) with air and water and examining for leaks – if any are detected the test is reported as having failed. Additionally, gloves which meet the EN 374-2 penetration tests may claim protection from bacteria and fungi according to EN 374-5 using this pictogram.
EN 374-5 also contains an optional viral penetration test (ISO 16604 Procedure B – to pass this test there must be no detectable transfer of the Phi-X174 bacteriophage, defined as <1 PFU/ml). If passed, the glove may claim protection from viruses in addition to bacteria and fungi using the below pictogram:
Related standard - EN 421: While not part of EN 374-1, the main requirement for gloves claiming protection from radioactive particle contamination under EN 421 (using the pictogram above) is a pass result in the EN 374-2 penetration test.
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