Tightness tests require temporarily installing equipment in the tank. A volumetric test involves filling the tank to a specified level and precisely measuring the change in level and temperature over several hours. Non-volumetric test methods include ultrasound techniques and tracer gas detectors. These are sophisticated tests and must be performed by trained, experienced professionals. In addition to tightness testing, you must use monthly inventory control.
Inventory control is basically like balancing a checking account.
After that, you must use monthly monitoring methods. Manual Tank Gauging One additional method, manual tank gauging, can be used for smaller tanks, but it has several restrictions. In order to meet the Federal leak detection requirements, this method can be used by itself only for small tanks up to 1,000 gallons. It requires keeping the tank undisturbed for at least 36 hours, during which no product can be added or removed. During that period, you measure the contents of the tank twice at the beginning and twice at the end of the test period every week.