In general terms advice from the HSE on stock management is as follows. Gas cylinders should not be stored for excessive periods of time. Only purchase sufficient quantities of gas to cover short-term needs. Rotate stocks of gas cylinders to ensure first in is first used. There will of course be occasions where a particular product is taken for a project and may then sit unused for an extended period. In the first instance you should determine whether the product is past its stability period. If it is then it is not recommended to use it. If there is no medium term likelihood of use for that product then it may well make more economic sense to return the cylinder, as there is likely to be a monthly rental charge. It is also worth noting that cylinders have periodic test dates as they are pressure receptacles.

The test date should be marked on the cylinder and all cylinders will have a test date ring. If in doubt note the colour and shape of the plastic ring at the cylinder neck and consult the supplier. It is not advisable to retain cylinders for extended periods beyond their test date.