Standard explainer · EN ISO 11612
EN ISO 11612 is the workhorse FR standard — and its label is a string of letters and numbers like "A1 B1 C1 E2". Each letter is a different kind of heat, each number a tested level. Decode the string and the garment tells you exactly what it's for.
How it works
EN ISO 11612 covers clothing protecting against heat and flame in general industry. Rather than one pass/fail, it tests up to six properties, each with its own letter and graded levels. A garment must pass the flame-spread test (letter A) plus at least one of the heat-transfer letters — so every compliant label reads "A-something plus more letters".
The letters matter because heat arrives differently in different jobs: a foundry throws molten metal, a furnace wall radiates, a flash fire is convective. Buying the wrong letters means paying for protection you don't have.
The codes
| Code | Protects against | Levels | Typical hazard |
|---|---|---|---|
| A1 / A2 | Limited flame spread (surface / edge ignition) | pass | The gateway test — every 11612 garment has it |
| B | Convective heat (flame-heated air) | B1–B3 | Flash fire, burner work |
| C | Radiant heat | C1–C4 | Furnaces, hot slabs, fire watch |
| D | Molten aluminium splash | D1–D3 | Aluminium smelting and casting |
| E | Molten iron splash | E1–E3 | Iron and steel foundries |
| F | Contact heat | F1–F3 | Handling hot surfaces and parts |
Reading a label
Take a typical foundry coverall marked A1 B1 C1 E2: it resists surface flame spread (A1), gives baseline protection against convective (B1) and radiant (C1) heat, and — the headline — level 2 molten iron splash protection (E2). That's a garment built for iron and steel work. The same fabric weight in an aluminium plant would be wrong: aluminium splash behaves differently and needs the D code.
Two practical notes. First, levels are minimum performance bands, not comfort grades — a B3 garment is heavier and hotter to wear than a B1, so over-speccing has a real cost in heat stress. Second, 11612 is often certified alongside arc (IEC 61482) and antistatic (EN 1149-5) on multi-norm garments — the energy sector's default, covered in the sector guide.
Buying
Questions
Each letter is a tested heat type: A1/A2 limited flame spread, B convective heat, C radiant heat, D molten aluminium splash, E molten iron splash, F contact heat. The number after each letter is the performance level — higher means more protection in that specific test.
The molten metal: D covers aluminium splash, E covers iron. They're tested separately because the metals behave differently on fabric — an iron-rated garment isn't automatically aluminium-rated, so foundries spec by the metal they pour.
No — 11612 garments resist ignition and self-extinguish, and grade protection against specific heat types. Nothing wearable is 'flameproof'. The standard's letters tell you which heat hazards the garment is actually tested against and to what level.
More protective in that test, yes — but heavier and hotter to wear. Over-speccing causes heat stress and unworn kit. Match the letters and levels to the assessed hazard rather than maxing every number.
Multi-norm coveralls, arc-rated kit and FR base layers from stock — with badging that doesn't void the certification.