Methods of leak testing underground storage tanks
- Gary Elder and Associates, Ft. Myers, FL (United States)
Current EPA requirements call for leak testing storage tanks to detect leakage of .05 gallons/hour which by most leak testing standards would, appear to be a very gross leak and one easy to detect and measure with the very sensitive leak detectors available today. However, when one considers the number of variables that affects the sensitivity and accuracy of the results for the test system, one begins to realize how difficult the leak testing really is. There are basically two groups of leak tests for underground tank examination; those leak tests that measure the amount of tank leakage (volumetric techniques) and those that only qualify that there is leakage. Because the EPA standards require an actual quantity of leakage, most leak tests are volumetric techniques. The volumetric leak tests fall into three categories. Liquid level change measurement is used for half of the tests and their claimed accuracy varies from gross to less than .02 gal/hr. The second group of volumetric tests methods are based on pressure change caused by the volume change and their claimed accuracy varies from gross to less than .05 gal/hr. The last type of volumetric leak methods are two tests based on the principle of buoyancy where the leakage is equated to the loss in weight of a object submerged in the liquid in the tank. These two methods are the Leak Lokator Test and the Tank Auditor and their claimed accuracy is .05 and .03 gal/hr (at center of tank). Qualitative leak test methods are primarily used to determine the presence of a leak and there are a number of test methods. Although the sensitivity and accuracy of some of these methods is much less than .05 gal/hr. for individual leaks under controlled conditions, this application on underground tank testing makes it impossible to accurately measure leakage. There are many leak test methods that can be used to test underground storage tanks and the results will vary for each. There is no best method.
- OSTI ID:
- 64661
- Report Number(s):
- CONF-931193--; ISBN 0-931403-23-5
- Country of Publication:
- United States
- Language:
- English
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