Compressed gases

The hazards
Compressed gases are used both in cylinders and from bulk containers across the University.  Risks may arise from the need to transport and handle gas cylinders (see manual handling section), from the release of cylinder contents (see chemicals section) or from sudden release of pressure due to system failure.  Whenever a compressed gas system (or even an individual cylinder) is present all of these risks exist and must be considered.  A formal risk assessment should be carried out on such systems, either generically or for individual systems where they are more complex or the risk from them is higher.

Release of contents may result in harm from toxic effects, flammability or asphyxiation depending on the material involved.  The potential for these outcomes must be considered as part of a risk assessment and suitable emergency procedures established to deal with such occurrences.

Recognised "industry standard" information on good practice is available within a range of Codes of Practice published by British Compressed Gases Association.  These should be adopted as working standards whereever practicable.

SEPS provide some detailed advice on design, operation and management of compressed gas systems and on statutory examination of pressure systems in general.  This is hosted within our Chemical Safety section but is also available from the quicklinks on this webpage.

Essential legal requirements
Fixed systems normally fall within the requirements of legislation covering pressurised equipment and will require a written scheme of periodic examination, periodic thorough examination in accordance with the scheme and replacement of certain component parts at regular intervals.  An external contractor is needed to draw up a suitable scheme and to carry out periodic examinations of the system. At the moment,  Zurich Engineering, part of Zurich Insurance Group provide these services to the University. SEPS can put you in touch with the appropriate Zurich Engineering surveyor if you need these services and are not already in contact.

Note that Zurich examinations do not constitute maintenance, and maintenance is not the same as thorough examination.  These are two separate things, both of which are legally required.  You need to have arrangements in place for BOTH.

Management of inventory and disposal of cylinders
In many cases when compressed gases are purchased the cylinder in which they are supplied remains the property of the supplier and is returned to them at no cost when its contents have been used. When this is not the case (for example 'lecture bottles'), or when a cylinder is retained beyond a point where the supplier is able to accept its return, the cost of disposal rests with the purchaser. It should be noted that the cost of disposal of this type of waste can be extremely high, even in cases where any residual content may not be highly specialist or extremely hazardous. It is, therefore, good practice to ensure that cylinders are returned promptly, where appropriate, and that those that cannot be returned are disposed on  a regular basis so as to minimise cost. Further information on the disposal of chemical waste is available in the waste management section of SEPS web site.