Magnetic flux leakage as applied to aboveground storage tank flat bottom tank floor inspections
- MFE Enterprises, Inc., Humble, TX (United States)
Magnetic flux leakage inspection techniques have been widely used in the oil field inspection industry for over a quarter of a century for the examination of both new and used pipe, tubing, and casing. It is only in the last 10 years that this inspection technique has been applied to aboveground storage tank (AST) flat bottom floors in an attempt to provide a reliable indication of the overall floor condition within an economical time frame. In most cases these inspections are being carried out by industrial inspection NDT companies who do not have the depth of experience in the technique that most of the oil field tubular inspection companies have. At the same time this relatively new application of magnetic flux leakage brings with it some additional problems not evident in the inspection of tubulars, where certain parameters can be quite closely controlled. Probably the greatest of these problems is that tank floors are never flat, whereas tubulars are generally always round. The ability to obtain any reasonably consistent quantitative information is seriously impacted by this general unevenness of most tank floors. The application of rigid accept/reject criteria based on signal amplitude thresholds has proved to be unreliable as regards truly quantitative information. A more realistic approach is required in the application of this inspection technique and in the design of the inspection equipment to ensure that there are fewer incidences of significant defects being missed. This article outlines some of the major considerations that need to be addressed in order to achieve reliable, fast, and economical inspections of AST flat bottom tank floors.
- OSTI ID:
- 197659
- Journal Information:
- Materials Evaluation, Journal Name: Materials Evaluation Journal Issue: 1 Vol. 54; ISSN MAEVAD; ISSN 0025-5327
- Country of Publication:
- United States
- Language:
- English
Similar Records
A new method for fast tank floor inspection
Nondestructive inspection requirements for aboveground storage tanks