Drager Filter Colour Code Guide
Respirator filters are colour-coded according to EN 14387, a standard used across the EU and many other countries. These colour codes help you quickly see what each filter protects you from. The colours printed on the filter show which gases, vapours, or particles it can block.
For a full breakdown, see our guide to respiratory filter codes, but here’s a simple summary:
AX (Brown): Organic gases and vapours with a low boiling point (≤ 65 °C).
A (Light Brown): Organic gases and vapours with a higher boiling point (> 65 °C).
B (Grey): Inorganic gases and vapours, e.g. chlorine, hydrogen sulphide, hydrogen cyanide.
E (Yellow): Acid gases and vapours, e.g. sulphur dioxide, hydrogen chloride, formic acid.
K (Green): Ammonia and organic ammonia compounds, e.g. hydrazine, methylamine
CO (Black): Carbon monoxide
Hg (Red): Mercury vapours
NO (Blue): Nitrogen oxides and similar nitrous gases
Reactor (Orange): Radioactive iodine, including radioactive methyl iodide
P (White): Particles
