Overview

Whilst gases are sometimes prepared in situ for cost and safety reasons (e.g. to remove the risk associated with their transport, storage and piping to point of use) they are more often stored on an industrial scale at low pressure, either under refrigerated conditions, e.g. cryogens (Chapter 8), or at ambient temperature in 'gasholders', which 'telescope' according to the quantity of gas and are fitted with water or oil seals to prevent gas escape. Smaller quantities of gas at high pressure are usually stored in bottle-shaped gas cylinders. They find widespread use in welding, fuel for gas burners, hospitals, laboratories etc. The construction of compressed gas cylinders ensures that, when first put into service, they are safe for their designated use. Serious accidents can, however, result from ignorance of the properties of the gases, or from misuse or abuse. Great care is needed during the transportation, handling, storage and disposal of such cylinders.

Compressed gases can often be more dangerous than chemicals in liquid or solid form because of the potential source of high energy, low boiling-point of some liquid contents resulting in the potential for flashing (page 50), ease of diffusion of escaping gas, low flashpoint of some highly flammable liquids, and the absence of visual and/or odour detection of some leaking materials. The containers also tend to be heavy and bulky.

Compressed gases, therefore, present a unique hazard from their potential physical and chemical dangers. Unless cylinders are secured they may topple over, cause injury to...