Spherical vessels dedicated to storing liquefied gases under pressure — LPG, propane, butane, ammonia. The spherical geometry is the most structurally efficient solution for internal pressure: for a given pressure, the required wall thickness is half that of a cylinder of the same diameter.
Characteristics
- Typical volumes: 1,000 to 12,000 m³.
- Design pressure: 15 to 18 barg (LPG conditions).
- Construction: prefabricated hemispheres field-welded onto columns with thermal expansion systems.
- Safety: mandatory water deluge cooling system, duplicated relief valves, lightning grounding.
Reliability: external corrosion of support columns (often CUI), fatigue at pipe connections, degradation of the deluge system (frequently a hidden function — periodic proof testing is mandatory). BLEVE is the catastrophic scenario that drives the entire maintenance strategy.