Failures pump, explosion from

At 2 20 A M., another explosion occurred, the BLEVE of sphere 407. Its fireball was less intense than the earlier one. The sphere s top section traveled 190 m (620 ft) and caused the destruction of a firewater tank and one of the plant s fire pumps. Other sections further damaged other units. The pressure relief valve of this sphere traveled 500 m (1600 ft). The damage from projectiles was much greater than that caused by the first sphere failure because they traveled farther and in more damaging directions. 

Liquids under pressure (pipeline leaks, pump seal failures, etc.), will be thrown some distance from the point source, while atmospheric leakages will emit at the point of release. The other characteristic of liquid releases is their flash points. High flash point liquids, not operating above their flash point temperatures, are inherently safer than low flash point liquids. Most liquid fires are relatively easy to contain and suppress while gas fires are prone to explosion possibilities if extinguished and source points are not isolated. 

Small towers sometimes are reinforced PVC, and there is no need for a lining. A potential problem with PVC or other nonconductive material is the accumulation of a static charge. The explosion of a set of three PVC dryers in a mercury-cell plant was attributed to static discharge in the presence of an explosive gas [27]. The root cause of the incident was the failure of the power supply to the mercury pumps, which allowed mercury to drain from the cells and uncover the steel bottoms. This led to the formation of large quantities of hydrogen. The investigators concluded that towers should be constructed of acid-proof conductive material that can be held at ground potential. 

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