NDTnet 1998 Aug, Vol.3 No.8

Abstract

The reliability in operation of underground tanks intended for storage of petroleum products is determined not only by the quality of construction but also by the system of diagnosis of their shell. The main problem of overall diagnosis of the tank shell consists in detection and prevention of the development of defects in welded joints and sheet metal, in determining their parameters and causes of appearance. The leaks are the most dangerous defects in the shell. They result in the losses of a stored product, environmental pollution as well as in considerable spending of time for their search and remedy.

The defects, arising during construction and operation of underground tanks for storage of petroleum products and the factors of choice of NDT technology are analyzed in the paper.
We have offered the flow charts for non-destructive testing in construction of a tank, during its scheduled diagnosis and in the search for a point of leak of a stored product with subsequent repair of the tank. They differ from each other in the sequence and scope of operation and foresee the carrying out of thorough visual inspection, tests for tightness of welded joints and shell metal, measurement of the shell thickness with the aid of a hand-operated or mechanized ultrasonic thickness gauge, magnetic-particle testing of welded joints after repair jobs as well as selective X-ray testing or ultrasonic testing of welded joints.
The metal shell of an underground tank from the point of view of the technology of tests for tightness is an open sheet structure with a one-sided access. The vacuum chamber method is the most rational way of testing for tightness of the welded joints and shell metal under these conditions.
The paper also describes the tanks shell testing facilities.
Overall diagnosis of underground metal tanks with one-side access to shell was made for various enterprises in the Community of Independent States.

Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00

Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:

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