Gas cylinder colour codes and safe handling: an EN 1089-3 guide

The fastest way to tell what a cylinder holds is its shoulder colour. But the colour code is a convenience, not a definitive source: the label on the cylinder always takes precedence. This article collects the EN 1089-3 colour coding, the colours of common gases and the rules for storage.

How to read the colour code

• The shoulder colour carries the meaning: it identifies the gas itself or its hazard class.
• The body colour is not set by the standard and varies between manufacturers and fillers. Never identify a gas from the body colour.
• The letter “N” on the shoulder shows the cylinder is marked to the new colour coding. This matters during transition periods when old and new coding coexist.
• The label governs. Paint fades and cylinders get repainted; the label and the stamped markings are binding.

Shoulder colours by hazard class

Colours of commonly used gases

For most common gases the standard defines a specific colour that replaces the hazard colour:

For mixtures the shoulder colour follows the dominant hazard of the mixture. For argon–carbon dioxide mixtures, for instance, the label is always the correct source; you can review the data sheets in our gas guide.

Storage rules

• Cylinders must stand upright and be secured with a chain or clamp so they cannot topple.
• The storage area must be ventilated; avoid basements, pits and enclosed volumes. Gases heavier than air (argon, carbon dioxide) collect at floor level.
• Keep away from heat sources, direct sunlight and electrical panels.
• Oxidising gases (oxygen) are stored separately from flammable gases (acetylene, hydrogen); where the separation distance cannot be met, use a fire-resistant partition.
• Mark full and empty cylinders separately and operate first-in, first-out.
• The valve cap must be fitted when not in use. Never lift a cylinder by its cap.

Transport and use

1. Never roll or drag a cylinder; use a proper trolley.
2. Remove the regulator and fit the valve cap before moving.
3. Before fitting the regulator, clear dust from the valve outlet with a brief purge, keeping your face away from the outlet.
4. Check joints for leaks with a foaming solution, never with a flame.
5. Do not fully empty a cylinder; leaving positive pressure inside prevents suck-back and contamination.
6. Close the valve and purge the line when you finish.

Special care with oxygen

An empty cylinder is not empty

A cylinder called “empty” always holds residual gas and pressure. Empty cylinders are transported and stored under the same rules as full ones. For equipment, hose and regulator selection see our gas equipment family, or ask us for hardware suited to your application.