EN ISO 11612

EN ISO 11612

Clothing to protect against heat and flame

EN 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

11612A (ISO 15025)

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). This test is also used for EN 531A. The application of a flame can take place in two ways:

  • in procedure A (leads to Class A1), the flame is applied horizontally (similarly to EN 470 and EN 531)
  • in procedure B (leads to Class A2), the flame is applied laterally.


11612B (ISO 9151)

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.

B1: 4 < 10 seconds

B2: 10 < 20 seconds

B3: 21 seconds and longer


11612C (ISO 6942)

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 0C is measured. The test procedure is the same as EN ISO 11611, but the classification is different:

C1: 7 < 20 seconds

C2: 20 < 50 seconds

C3: 50 < 95 seconds

C4: 95 seconds and longer


11612D en E (ISO 9185)

Determining the level of protection against spatters of molten metal. A membrane (with similar properties to human skin) is attached to the reverse of the fabric sample. Subsequently, 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.

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


11612F (ISO 12127)

A new test supplementing 531): contact heat. The classification in this respect:

F1:  5 < 10 seconds

F2: 10 < 15 seconds

F3: 15 seconds and longer



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)

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.

Hardware must be covered on one side and there must be sufficient overlapping between jacket s and trousers (20 cm when standing upright).


Similarly to EN 531, a number of model requirements only apply if codes D and/or E are used:

  • sleeves and trouser legs may not be turned up
  • exterior pockets must have flaps that are 10 mm wider than the actual pocket on both sides. This rule does not apply to side pockets below the waistline with openings placed at an angle of less than 10° to the vertical seam. This rule corresponds to the requirements in EN ISO 11611 Welder's clothing (and is an easing of the specifications for models in EN 531 D/E).


Fastenings must have:

  • a protective flap
  • max. distance between buttons of 15cm
  • neck openings must have a fastener
  • trouser legs may have side slits, provided they can be fastened and that the slit and fastening are covered by a flap.


Changes compared to EN 531

  • The lining must have the same flame retardant properties as code A outer material (no after flame burning, melting or hole formation)
  • Flame retardancy is (also) tested after the maximum (= 50) washes
  • Requirements for the seams in respect of strength (min. 225 N) and flame retardancy
  • Flame retardancy and heat resistance of sundries.