(83b) Management of Risk for Large Flat Bottom Liquid Oxygen Storage Tanks

Low pressure flat bottom tanks (FBTs) are widely used in the chemical and associated industries for storage of non - hazardous and hazardous liquids. The chemical industry has, for many years, considered the possibility of catastrophic failure of these tanks as a credible event and has designed hazardous material tank installations to reduce the risk from such events.

This paper summarizes the possible causes of failure of cryogenic Liquid Oxygen Flat Bottom Tanks (LOX FBTs) and describes incidents where failures of cryogenic FBT vessels have occurred. Large spills of liquid oxygen have the potential for serious consequences to people, buildings and vehicles on adjacent roads. The likelihood of failure of LOX FBTs should be reduced by careful design and stringently controlled construction methods, and the consequences of failure should be mitigated by careful selection of the location of the tank or, if this is not possible, by measures such as secondary spill containment.

The paper discusses the risk reduction options that can be considered and recommends how the decision on selecting a location for a LOX FBT should be approached.