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 in use 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.
Fixed systems will normally fall within the requirements of the legislation covering pressurised equipment and will require a written scheme for periodic examination and replacement of certain component parts at regular intervals. An external contractor may need to be engaged to draw up a suitable scheme and to carry out periodic examinations of the system in accordance with it. More detailed guidance is available from this link: Gas Cylinder Piped Systems
Note that ALL compressed gas systems will also require an appropriate maintenance regime. This is not the same as the “thorough examination” but many gas companies do prefer to offer a combined contract for both elements.
The Health and Safety Executive have published detailed advice on safe use of gas cylinders: http://www.hse.gov.uk/cdg/pdf/safusgc.pdf
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.
In many cases when compressed gasses 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/Management Unit that ordered it. 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 section of SEPS web site.