Importance of Colour Coding for Gas Cylinders and Lines in Laboratories

Colour coded Gas Cylinders

Gases constitute an essential utility in modern-day laboratories. Examples of gases commonly used are compressed air, zero air, nitrogen, helium, argon, hydrogen, nitrous oxide and acetylene. Operation of laboratory instruments such as Gas Chromatographs, Atomic Absorption spectrometers, ICP’s and Mass spectrometers is unthinkable without provision of required gases.

Let us begin by imagining a scene where a laboratory makes use of several gases but colour practices are followed.In such a situation though the chemist and technicians may be trained and confident but there is always scope for human error and catastrophic situations may arise due to:

• Wrong gas supplies being connected to instruments
• Storage of hydrogen or other combustible gases in vicinity of oxidant gases or storage in poorly ventilated areas which can result in formation of combustible gas mixtures.
• Fixing of non-compatible gas regulators to the gas cylinders
• Unsafe gas handling like storing of non- compatible gases or allowing passage of such gases in lines in vicinity of each other

Such potential laboratory hazards can be prevented by using the prescribed colour coding for gas cylinders and gas lines. It should be mandatory for every laboratory to make use of colour coded gas supply tanks and gas lines.

How to handle gas chromatographic gases safely provided some useful tips for handling of gases in a gas chromatography laboratory.You will not have to worry about getting the gas cylinders painted on receipt to the required specifications at it as it is the responsibility of the gas manufacturer to distribute. only prescribed colour coded cylinders.

Colour coding is helpful in identification of gas cylinders and lines even by laymen provided they are familiarised with such colour codes. Almost all countries follow their own guidelines but efforts have been made to prescribe universal colour coding. British Compressed Gases Association introduced cylinder identification and colour coding scheme through BS EN 1089 – 3 which has been harmonised in the European Union. The colours used for medical gases are harmonised on the basis of ISO 32 standard

The colour coding is applied to the shoulder or the curved portion of the cylinder and it identifies the property of the gas inside the cylinder.

• Yellow – toxic
• Red – flammable
• Light blue – oxidising
• Bright Green – inert

A gas cylinder having two concentric colour bands indicates a combination of properties. The body of the cylinder can be of any colour of manufacturer’s choice but it should not lead to confusion regarding risk associated with the gas as indicated by the shoulder colour.

For the purpose of easy identification and the shoulder colours can refer to the gas inside the cylinder. Some typical examples are:

• Maroon – acetylene
• Grey – carbon dioxide
• Brown-helium
• Red – hydrogen
• Blue – Nitrous oxide
• Black – nitrogen
• White – oxidant.

In addition to the colour coding it is helpful if a label is a fixed which bears the name of the gas inside the cylinder.

It is important for all laboratories to prominently display colour code charts in workplace as well as in gas storage space so as to familiarise the workers with associated hazards of gases and their potential hazards..