Polymer composite corrosion-resistant tanks – comparative evaluation of polish and foreign design standards
Andrzej Bełzowski Politechnika Wrocławska, Wydział Mechaniczny, Wydziałowy Zakład Wytrzymałości Materiałów, ul. Smoluchowskiego 25, 50-370 Wrocław
Quarterly No. 3, 2005 pages 56-61
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abstract A comparative analysis of some basic concepts adopted in standards for design and construction of large-size corrosion-resistant tanks has been presented. The last two editions of Polish standards were compared with the corresponding British, American and French counterparts, the principal attention being paid to anticorrosion coatings, safety factor determination and assessment of newly constructed structures. Significant shortcomings in all the named aspects were found in the Polish codes. The protective layers which are of prime importance in this type of structures are vaguely defined in the documents. A forensic study of a tank whose badly inadequate inner lining was a prime cause of the unrepairable failure (Figs 1, 2) has been presented. The analysis of the safety factor determination approach shows that Polish standards tend to be overly optimistic and thus the resulting designs are less safe than those specified by the foreign codes. For newly constructed tanks the Polish codes require no destructive tests of bearing capacity and no fatigue tests which is contrary to requirements set by many foreign specifications. The presented analysis proves that the last edition of the Polish codes leaves much of the shortcomings unamended. The quoted tank failure study shows in detail how imprecise and vague design standards combined with inadequate inspection policies lead to industrial disasters. Key words: polymer-matrix composites, laminates, chemical-resistant tanks