Design of safety valves and rupture disks for storage tanks for cryogenic gases

The increasing level of standardisation of systems for cryogenic gases means that precise design of pressure relief systems is vital, particularly in view of the potential effects of an incorrectly designed safety valve or a supply line of inadequate dimensions. The costs when an unscheduled replacement campaign becomes necessary as a result of an incorrectly dimensioned valve can be horrendous. The service lives of safety valves will increase significantly if these elements are designed separately from one another for maximum mass flows for the fire load, and minimum mass flows in case of entirely thermal expansion - the practice which most closely approximates to normal operation. The article outlines the necessary procedure.