When using oxygen or any medical gases, it is imperative that patient equipment is connected to the correct medical gas cylinders.

Failure to do so can lead to patients being given the wrong gas, or the right gas at the wrong pressure. Both can have fatal consequences.

Traditionally, the valve outlets used for medical gas cylinders in the UK and Ireland have been shared across a number of different gas types. One way of minimising this risk is to ensure that different standards and outlets are used for different medical gases.

As part of our work on Technical Sub Committee 7 – Medical Gases, for the British Compressed Gases Association (BCGA), our team was involved in the creation of Technical Information Sheet 21: Medical Gases – BCGA Policy on Valve Outlets.

You can read BCGA TIS 21 in full here.

Technical Information Sheet 21 – An Overview

The guidance document provides in depth information on the different standards that can be used for medical gas cylinders to minimise risk and improve patient safety.

It covers:

  • Valve outlet standards
  • Converting non-oxygen cylinders and the benefits of changing
  • Colour coding and minimising risk
  • Engaging with healthcare customers on the conversion process

Medical Gas – Valve Outlet Standards Explained

There are three main standards that can be used in the UK and Ireland when specifying the cylinder valve outlets for medical gas cylinders. These are:

BN EN ISO 407 [2] – for small gas cylinders

This refers to pin-index yoke type connections, typically used on cylinders up to 5L in capacity. It provides up to 16 different outlets for a range of different medical gases.

BS ISO 5145 [3] – gas cylinders

This standard includes a number of connections for different medical gases and mixtures. It is used primarily for the filling connection for valves with internal pressure regulators, but can also be used on medical gas cylinders with non-pressure related outlets to provide a different valve connection for higher pressure cylinders.

BS 341 Part 3 [1] – transportable gas cylinders

This standard is used to specify all other cylinder valve outlets. Although it provides unique, product specific valve outlets for nitrous oxide and carbon dioxide, it specifies the same 5/8” BSP bullnose valve outlet for use in a range of different medical and industrial gases and mixtures.

Converting Cylinders to Improve Safety

To minimise the risk of using the wrong cylinder package – a programme of change has been implemented to convert all non-oxygen cylinders to gas specific outlets.

As part of the process, medical oxygen cylinders will be the only medical gas cylinders fitted with the same BS 341 Part 3 [1] 5/8” BSP bullnose valve outlet. All other medical gas cylinders fitted with bullnose valves will be converted to product specific valves, or will have the bullnose valves replaced with valves with integrated pressure regulators.

This process will be supported by other changes to medical gas cylinders, including the ongoing programme to change the body colour code to white. Take a look at our previous blog on medical colour coding here.

The Technical information sheet includes full details on the steps suppliers are taking, how this process will work, and how these changes should be communicated to customers.

Medical Oxygen Cylinders from AMS Composite Cylinders

AMS Composite Cylinders supplies state of the art, lightweight aluminium and carbon composite gas cylinders for a wide range of healthcare, homecare, breathing gas and medical gas applications.

We supply clients across the UK, Europe, the Middle East and Latin America, providing industry leading quality, reliable service and short lead times.

Producing cylinders to a wide range of recognised global standards, we hold accreditations in all major markets worldwide. We manufacture to ISO and EN standards (including ISO-11119-2, ISO 11119-1, EN 12245, EN 12257, ISO 7666, ISO 11118 and EN12245) and to the requirements of UN PED/TPED, DOT (USA) and TC (Canada).


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For additional information AMS Composite Cylinders, our medical gas cylinders and our accreditations, please contact us today.