CLOTHING TO PROTECT AGAINST HEAT AND FLAME
EN ISO 11612: protective clothing for workers exposed to heat and flames (not including welders and firefighters).
This means that the wearer is protected against brief contact with a flame and against (a limited amount of) convective and radiant heat. EN ISO 11612 is scheduled to replace EN 531.
The contents of this standard
The pictogram is given above and is the same as EN 531. This standard has a number of fabric tests. The results of the tests are represented by the letters A, B, C, D, E and F. If a letter is not specified, or if a class is given as “0”, the corresponding lowest test value has not been attained, or the de test has not been carried out (which means the clothing does not have the respective protective properties).
Different tests, codes
| Code Letter (Requirements) | Description | Test Method |
|---|---|---|
| Procedure A (Class A1), Surface ignition Procedure B (Class A2), Edge ignition | This test consists of applying a flame to a fabric sample for 10 seconds. To pass the test, the after flame & smoulder times and formation of holes must be within the tolerances (set in the standard). The application of a flame can take place in two ways: | ISO 15025 |
| B1: 4 < 10 seconds B2: 10 < 20 seconds B3: 21 seconds and longer | Convective heat: determination of the heat transmission when exposed to flames. The sample is held above the flame and the rise in temperature on the topside of the sample is measured with a calorimeter. Subsequently, the length of time the sample can remain exposed before its temperature rises by 24 °C is determined. | ISO 9151 |
| C1: 7 < 20 seconds C2: 20 < 50 seconds C3: 50 < 95 seconds C4: 95 seconds and longer | Exposure to radiant heat. In this test, a fabric sample is exposed to radiant heat (infrared rays). The temperature on the reverse (unexposed) side of the sample is registered using a calorimeter. Subsequently, the length of time the sample the sample can remain exposed before its temperature rises by 24 °C is measured. The test procedure is the same as EN ISO 11611, but the classification is different: | ISO 6942 |
| The classification for molten aluminium is: D1: 100 < 200 grams D2: 200 <350 grams D3: 350 grams and more The classification for molten iron is: E1: 60 < 120 grams E2: 120 < 200 grams E3: 200 grams and more | Sequentially rising quantities of molten metal (for the D value – molten aluminium and for the E value – molten iron) are splashed on the sample. The quantity of molten metal which deforms the membrane is determined. | ISO 9185 |
| F1: 5 < 10 seconds F2: 10 < 15 seconds F3: 15 seconds and longer | This test method for the determination of contact heat transmission. It is applicable to protective clothing | ISO 12127 |
| Average | Optional test for protection against rain. The first “n” refers to the waterproofing class, the second “n” to the water vapour permeability class (see Section 11: EN 343 for explanation) | ISO 11612 |
The requirements set in this standard
The respective clothing must always comply with the flame spread code A1 or A2 and at least 1 of the other codes (B to F). The label must indicate the class that the fabric has attained.