Acoustic emission leak detection in above-ground storage tanks

The integrity of above-ground storage tanks is vital to a company's profitability, particularly in the petrochemical and chemical industries. Unfortunately, on these structures, conventional inspection techniques, such as visual testing and still gaging, are inaccurate, time-consuming, and costly. Conventional tank inspection methods have two pitfalls. First, they have limited sensitivity. Very often, still gaging inspection is significantly affected by temperature variances, the operator's visual interpretations, or mechanical errors. At best, still gaging has a liquid level error factor of +-0.125 in. (3.175 mm). In a large tank, that leaves room for a significant stock loss. Second, the tanks scheduled for integrity checks aren't always the tanks with problems. A company's maintenance staff can spend weeks on still gaging and internal inspections, only to find no problems in those tanks. In the meantime, an uninspected tank could be leaking.