Cylinder Care

Correct cylinder care is vital. If grit, dirt, oil or water get into the cylinder valve then safety and/or quality may be compromised

Valve care

If grit, dirt, oil or water enters the cylinder valve then safety and/or quality may be compromised and gas leakage may occur.

To help prevent contamination of the cylinder valve prior to use BOC fit valve security caps. It is recommended that these security caps are not removed until directly before use to reduce the risk of contamination.

Before assembling regulators and fittings, it is extremely important to ensure there are no particles of dirt in the cylinder outlet.

Use a dry, clean, lint-free cloth to wipe away any debris, being sure not to push any material into the valve socket. If a supply of clean compressed air or nitrogen is available this may be used to blow out any loose particles of dirt from the valve sockets – noting that suitable safety controls are required, including eye and ear protection.

Avoiding cylinder contamination – backflow

Backflow occurs when air or gas enters a cylinder by flowing through an open or unsealed valve.

Safety hazards are created if this is allowed to happen.

Precautions must be taken to ensure that no backflow of liquid, air or gas can occur either when the cylinder is connected or when it is in storage.

Backflow Preventative measures

To avoid contaminants entering the cylinder, the valve must be closed immediately after the gas use has ceased.

When cylinders are connected to a system or process in which the process pressure can exceed the actual cylinder pressure, adequate precautions must be taken to avoid backflow in the cylinder.

The following should be observed:

Always close the supply cylinder valve when the cylinder is not in use
Never leave an empty cylinder connected to a process
Never use a cylinder as a receiver for waste gas, liquid or other material
Fit and maintain appropriate equipment to help prevent backflow.

Fit a non-return or check valves

This is a simple and usually inexpensive measure to help prevent back-flow and cylinder contamination. However, these valve types require appropriate design and selection, and need regular inspection and maintenance to ensure that they remain effective over time.

Fit an automatic shut-off/isolation-valve

These valves are activated by a low pressure signal when the supply gas cylinder pressure reaches a level which requires the cylinder to be replaced.

An alarm should normally be incorporated into the system to alert the operator to change the cylinder.

More complex systems may use auto-change-over arrangements, to automatically switch to ‘standby’ cylinders when the supply pressure falls to a pre-determined level.

What to do if your cylinder becomes contaminated

If you suspect a cylinder has become contaminated, by whatever means or whatever the contamination, you must inform BOC immediately.

Before the cylinder is returned, please ensure that you label the cylinder and provide any relevant information about the known or suspected contamination.

This information is required even if the contaminant, such as water, has been emptied out of the cylinder before return.

Please note:

Never let oil or grease touch a cylinder or fittings. Lubrication of cylinder valves and fittings is highly dangerous as well as unnecessary. High pressure oxygen will react violently with grease; it may explode or ignite violently
Never use jointing compounds. Do not apply white or red lead, jointing compounds or jointing tape to any cylinders, valves or fittings

Oxygen equipment is at most risk from oil and grease: greasy hands, rags and gloves must not come into contact with any part of the cylinder or fittings
Normal body oils do not usually cause contamination, but it is a sensible precaution never to touch any surface which is subject to oxygen under pressure.