EN ISO 11612
Heat and flame
The EN ISO 11612 standard defines protective clothing that shields against heat and flame hazards. It sets the minimum performance requirements for garments exposed to brief contact with flame, heat, sparks or molten metal – ensuring tested, reliable performance wherever thermal risks are part of the job.
When to use EN ISO 11612 garments
EN ISO 11612 garments are worn in environments where workers face exposure to heat, flame or molten materials. They are commonly used in metalworking, foundries, maintenance, energy production and other processes involving sparks or high-temperature surfaces. These garments form a dependable layer of defence against short-term thermal risks.
Performance requirements under EN ISO 11612
To comply with the EN ISO 11612 standard, a garment must meet at least two performance categories:
limited flame spread (code letter A)
andprotection against heat (code letter B, C, D, E, F).
Each letter is followed by a number indicating the protection level, with higher numbers representing better performance. The following sections explain each performance category in detail, showing the test methods, performance levels and what they mean in practice.
EN ISO 11612 Performance requirements
Protection against flames
(A)
EN ISO 11612 Protection against flames
A – Limited flame spread
A garment that meets A1 or A1 + A2 provides protection against brief contact with flame, preventing it from spreading over the surface of the fabric or along the edges. This protection is the basis of the standard, ensuring that the flame does not continue burning once the ignition source is removed.
| Code | Description | Ignition type |
|---|---|---|
| A1 | Limited flame spread | Surface ignition |
| A2 | Limited flame spread | Bottom-edge ignition |
Surface ignition
Bottom edge ignition
EN ISO 11612 Performance requirements
Protection against heat
(B to F)
Each of the following code letters refers to a type of heat hazard and defines how the material reacts to it. These parameters are based on avoiding second-degree burns.
EN ISO 11612 Protection against heat
B – Protection against convective heat
Convective heat transfer is the transfer of heat between two bodies by currents of moving gas or fluid. The test values indicate the time it takes for the skin temperature under the fabric to increase by 24°C - the point at which a second-degree burn could occur.
| Level | Min. | Max. |
|---|---|---|
| B1 | 4 s | < 10 s |
| B2 | 10 s | < 20 s |
| B3 | 20 s |
EN ISO 11612 Protection against heat
C – Protection against radiant heat
Radiant heat exposure is common near hot surfaces or molten material. The C-values refer to the time it takes for the temperature beneath the fabric to increase by 24°C, the point at which a second-degree burn may occur. The limits shown in the table indicate the fabric’s ability to block radiant heat - the higher the value, the longer the fabric delays heat transfer to the skin.
| Level | Min. | Max. |
|---|---|---|
| C1 | 7 s | < 20 s |
| C2 | 20 s | < 50 s |
| C3 | 50 s | < 95 s |
| C4 | ≥ 95 s |
EN ISO 11612 Protection against heat
D – Protection against molten aluminium splash
The test measures how much molten aluminium (by weight) the fabric can withstand before the temperature rise on the reverse side reaches 24°C, the threshold at which a second-degree burn may occur. The result is the amount of poured metal reached without damaging the PVC film placed underneath the fabric sample. When a material resists molten aluminium splashes, it is generally also suitable for protection against bronze or molten minerals.
| Level | Min. | Max. |
|---|---|---|
| D1 | 100 g | < 200 g |
| D2 | 200 g | < 350 g |
| D3 | ≥ 350 g |
E – Protection against molten iron splash
Radiant heat exposure is common near hot surfaces or molten material. The C-values refer to the time it takes for the temperature beneath the fabric to increase by 24°C, the point at which a second-degree burn may occur. The limits shown in the table indicate the fabric’s ability to block radiant heat - the higher the value, the longer the fabric delays heat transfer to the skin.
| Level | Min. | Max. |
|---|---|---|
| E1 | 60 g | < 120 g |
| E2 | 120 g | < 200 g |
| E3 | ≥ 200 g |
EN ISO 11612 Protection against heat
F – Protection against contact heat
The test measures how long the fabric can withstand contact with a hot surface at 250°C before heat is transferred through to the inside. The result is the threshold time — the time between the start of the test and the moment when the temperature on the reverse side has increased by 10°C above its starting value. This indicates how quickly heat is transmitted through the material and how effectively the fabric delays the onset of a burn.
| Level | Min. | Max. |
|---|---|---|
| F1 | 5 s | < 10 s |
| F2 | 10 s | < 15 s |
| F3 | ≥ 15 s |
About the symbol
For example, the Atiras ECO work jacket with ARC protection (APC1) from the Multinorm UP collection is certified as EN ISO 11612: 2015 A1 A2 B1 C1 E3 F1. This means it has been tested for surface and edge ignition (A1 + A2) and provides level 1 protection against convective heat (B1) and radiant heat (C1), level 3 protection against molten iron splash (E3), and level 1 protection against contact heat (F1). It does not offer certified protection against molten aluminium splash (D).
Correct use and maintenance of EN ISO 11612 garments
EN ISO 11612 garments are not intended for firefighting, as they are not aluminised, heat-reflective clothing. In the event of fire or exposure to flames, the wearer should move away from the flame or heat source as quickly as possible. Protection is no longer guaranteed after serious damage.
Contamination with flammable residues or chemicals such as oils or solvents can significantly reduce flame-retardant performance. If contamination occurs, the user must leave the area, carefully remove the garment to avoid skin contact, and have it properly laundered or replaced before reuse.
To maintain performance:
Ensure the clothing covers neck, torso, arms and legs fully.
Where protection is provided by an outer two-piece suit, an overlap of at least 20 cm must be maintained when bending.
Fasten all closures completely and wear as part of a full protective outfit.
Replace damaged or heavily soiled garments promptly.
Wash according to the care instructions inside the garment to preserve protection.