Many businesses use gas cylinders but won’t necessarily understand the labelling system that accompanies them. Yet, the markings and labels that come with each cylinder are crucial to ensuring safety, and that the correct handling procedures are used for each type of gas. Misidentification of gas cylinders can lead to health hazards, fire risks and regulatory compliance issues, so it’s important to be aware of the labelling systems used in gas cylinders.
Colour Coding: UK and International Standards
Colour coding systems in gas cylinders helps to identify the gas enclosed in the cylinder, or key properties of the gas that are necessary to be aware of. Colour coding applies to the curved part at the top of the cylinder, and if the gas contains multiple hazardous properties there might be two concentric bands or the colours may be painted in quarters around the shoulder. Gas cylinders appear in four main colours that reflect different properties of the gases:
Red (Flammable) – Red cylinders contain flammable substances, which can ignite with small sparks or even electrical components. The bold red colour used in these cylinders signifies their potential hazard.
Light Blue (Oxidising) – Gases that contain Oxidising properties, can be dangerous when mixed with flammable substances. Oxidising substances can also be fatal if inhaled, hence why colour coding systems need to be in place.
Yellow (Toxic and/or Corrosive) – Yellow cylinders mean that the enclosed substance is corrosive or toxic to either humans, plants or animals, and are corrosive to surfaces like metal or plastic. Carbon monoxide is an example of a toxic substance
Bright Green (Inert) – Inert gases are non-toxic and/or non-corrosive, non-flammable and non-oxidising, meaning that it does not react with other chemicals. Despite this, inert gases can still present hazards, like compressed argon that can cause health issues.
In addition to the four main cylinder colours, there are some gases that have been assigned their own distinctive colour, as they are more commonly used.
Acetylene (Dark Red) – Acetylene is also used commonly in welding as a fuel gas, due to its high flame temperature which is suited for joining and cutting metals.
Oxygen (White) – Compressed oxygen is one of the more common gases to be found in gas cylinders, especially in a medical setting.
Nitrous Oxide (Blue) – otherwise known as ‘laughing gas’, nitrous oxide has a range of applications across fields such as medicine, engineering and agriculture.
Argon (Dark Green) – Argon is a commonly used gas in the lighting industry, as it fills the majority of lightbulbs.
Nitrogen (Black) – Nitrogen is often used in dental procedures in combination with oxygen, and in agricultural production.
Carbon Dioxide (Grey) – Carbon Dioxide is another common gas, and has many industrial and medical uses.
Helium (Brown) – In addition to its balloon-filling features, helium has many industrial purposes, including welding.
This is the colouring system outlined by the British Compressed Gases Association (BCGA) and the International Organization for Standardization (ISO), meaning that the colours of gas cylinders are internationally recognised. To identify a gas cylinder that is coded in accordance with international standards have the letter ‘n’ marked twice on the cylinder shoulder, in a different colour to the cylinder colour. This is a requirement of the international standard, and is not necessary in the UK.
Even though the colour coding systems for UK and International gas cylinders align, you should always check the labels and markings on the cylinder to be sure of its contents, and avoid mixing gases that are hazardous. It should also be noted that gases used in medical settings have their own set of regulations, so it’s important to consult this to be sure of any differences.
Cylinder Labels
Cylinder labels are implemented to highlight specifications of the enclosed gas within a cylinder. They also include details such as how and when the cylinder was made, a unique serial number and any hazards. When inspecting the label of a cylinder, keep an eye out for these key details:
Diamond Hazard Labels – A diamond-shaped label displaying the hazards associated with the gas enclosed is the first thing you should search for on a gas cylinder. There might be one label, or a number of them, so be sure to read all potential hazards.
The UN Number – A number that begins with ‘UN’ is an identification code assigned by the United Nations to classify hazardous materials. This helps in the transportation of gases and are internationally recognised.
The proper shipping name – This shipping name will be clearly displayed, and helps in identifying the enclosed gas.
The product name – If the shipping name and product name are the same, the product name might be omitted.
Signal word, hazard, and precautionary statements – This will denote any precautions or storage instructions for the gas.
Package Size and Pressure – This refers to the pressure, size, and weight of the gas cylinder.
EC Number – Refers to the European Community number, which identifies any substances that are regulation under EU legislation.
Company Name.
Address of the Gas Company.
Additional Company Information.
Contact Phone Number.
Understanding the colour coding and labelling systems used in gas cylinders is vital practice for ensuring that all gases are handled safely, and that there is no confusion in the transporting of hazardous substances. It is furthermore important to purchase your gases through a trusted and reliable supplier that use proper labelling systems, such as Adams Gas. For more information regarding the identification and colour coding of gas cylinders, refer to our Gas Cylinder Identification page, or get in touch.
