European Standard · Protective Clothing
EN ISO 11612 – Clothing Protecting Against Heat and Flame
EN ISO 11612 is the European standard specifying requirements and test methods for garments made from flame-resistant materials designed to protect the wearer from heat and flame, covering convective heat, radiant heat, molten metal splash and contact heat depending on the coded protection letters achieved.
1. Scope
EN ISO 11612 applies to protective clothing used in environments with limited flame exposure and heat hazards such as welding, foundries, and industrial furnaces. It excludes firefighter clothing (covered by EN 469) and welding-specific clothing (covered by EN ISO 11611), though similar principles apply.
2. Exclusions & Related Standards
- Does not cover firefighter turnout gear – see EN 469.
- Does not cover welding protective clothing specifically – see EN ISO 11611.
- Often combined with flame-resistant high-visibility features under EN ISO 20471 for roadside or utility work.
- Built on the general clothing requirements of EN ISO 13688.
3. Key Requirements & Marking
Garments are marked with letter codes A1/A2 (limited flame spread), B1-B3 (convective heat), C1-C4 (radiant heat), D1-D3 (molten aluminium splash), E1-E3 (molten iron splash) and F1-F3 (contact heat), with higher numbers indicating greater protection within each category, depending on which hazards the garment is certified against.
4. Testing Overview
Testing includes limited flame spread exposure, convective and radiant heat transfer measurement, molten metal splash resistance, and contact heat transfer time, each performed using standardised heat sources and instrumented test rigs to measure heat transmission through the fabric.
5. Selection Guide
Select the specific letter-and-number combination matching your actual workplace hazards; a foundry worker needs strong molten metal splash resistance (D or E ratings), while someone working near industrial ovens may prioritise contact heat resistance (F rating) and radiant heat protection (C rating).
6. Inspection, Care and Maintenance
- Follow washing instructions precisely, as some flame-resistant treatments degrade with incorrect laundering
- Inspect for contamination with flammable substances such as oil or solvents, which can compromise flame resistance
- Replace garments once fabric becomes thin, torn or the flame-resistant finish has visibly degraded
- Do not iron or heat-treat garments beyond manufacturer instructions, as this can damage protective fibres
7. Frequently Asked Questions
What do the letter codes on EN ISO 11612 clothing mean?
Each letter represents a specific heat hazard category (such as B for convective heat or D for molten aluminium splash), and the number after it indicates the performance level, with higher numbers meaning stronger protection.
Is EN ISO 11612 the same as welding protective clothing?
No, welding-specific protective clothing is covered by EN ISO 11611, which includes additional requirements relevant to welding sparks and electrical risk.
Can EN ISO 11612 clothing be worn by firefighters?
No, firefighter turnout gear must meet EN 469, which includes additional requirements beyond general heat and flame protective clothing.
Does EN ISO 11612 clothing protect against chemical splashes?
No, chemical protection requires garments meeting EN 13034 or EN 14605 in addition to any heat and flame protection needed.
How do I know which heat protection level I need?
Conduct a workplace risk assessment identifying the specific heat hazards present (flame, radiant heat, molten metal, contact heat) and match the garment’s letter codes and levels to those hazards.