Chapter 4 - Storage Tanks

Abstract

Failure of large storage tanks can be devastating owing to impact damage from the sudden release of a fluid wave. Fracture of a polypropylene tank along a weld seam was caused by faulty design, and the walls could not withstand the hydrostatic internal pressure. The tank breached a German standard DVS 2205 with walls built like a barrel rather than like a dam. A paint tank also failed suddenly from a welded joint due to faulty design. Sewage storage tanks were rotationally moulded in HDPE but collapsed due to external groundwater pressure. The walls were not reinforced and crept under pressure. A mancab and traffic cones failed by UV degradation and should have been protected with special additives. Battery cases exposed to strong sunlight also fractured due to UV degradation, which was concentrated at the weld line owing to a faulty heater. Catastrophic failure of a fibreglass tank was caused by poor design with walls incapable of supporting the load and a bund wall which hid the deformation in its short life. The polymer wall could not withstand the high temperatures of boiling water and crept under load. Spirally wound tank walls have improved the design of tanks for hazardous fluids, but in one case, the plastic base failed and caused an acid leak. It was caused by excessive trimming at a thermal weld followed by crack growth.