How does the leak detection method work?
This method involves keeping the tank undisturbed for at least 36 hours each week, during which the tank’s contents are measured, twice at the beginning and twice at the end of the test period. Manual tank gauging can be used as the sole method of leak detection for the life of the tank only for tanks up to 1,000 gallons. Tanks between 1,001 and 2,000 gallons can use this method only in combination with tank tightness testing. This combined method, however, can be used only during the first 10 years following tank installation. The features of manual tank gauging are: • Four measurements of the tank’s contents must be taken weekly, two at the beginning and two at the end of at least a 36-hour period during which nothing is added to or removed from the tank (see “Table of Test Standards for Manual Tank Gauging”). • The average of the two consecutive ending measurements are subtracted from the average of the two beginning measurements to indicate the change in product volume. • Every wee
