UST Programs - LG 113

Issue Date: November 22, 1995
Revision Date: November 6, 1997

Western Environmental Resources

AES System II

VOLUMETRIC TANK TIGHTNESS TEST METHOD (OVERFILL)

Certification	Leak rate of 0.1 gph with PD = 97.7% and PFA = 2.3%.
Leak Threshold	0.05 gph. A tank system should not be declared tight if the test result indicates a loss or gain that equals or exceeds this threshold.
Applicability	Gasoline, diesel, aviation fuel, fuel oil #4. Other liquids with known coefficients of expansion and density may be tested after consultation with the manufacturer.
Tank Capacity	Maximum of 15,000 gallons. Tank must be minimum 100% full.
Waiting time	Between delivery and the beginning of test, waiting time is included in the waiting time after "topping off". Between "topping off" and beginning test, waiting time is computer-dictated by real-time analysis of level and temperature data. Total waiting time is approximately 4 to 12 hours. There must be no dispensing or delivery during waiting time.
Test Period	Minimum of 2 hours (two 1-hour tests). Test data are acquired and recorded by system's computer. Leak rate is calculated from the last 1 hour, 30 minutes of test period data. There must be no dispensing or delivery during test.
Temperature	Average for product is determined by a minimum of 5 temperature sensors.
Groundwater	Depth to groundwater in tank excavation backfill must be determined. If groundwater is above bottom of tank, product level must be adjusted to provide a minimum net pressure of 2 psi at bottom of the tank during test.
Calibration	Level sensors must be calibrated before each test in accordance with manufacturer's instructions. Temperature sensor must be checked annually and, if necessary, calibrated in accordance with manufacturer's instructions.
Comments	Not evaluated using manifolded tank systems.

Western Environmental Resources	Evaluator: Vista Research
PO Box 37	Tel: (415) 966-1171
Bakersfield, CA 93302	Date of Evaluation: 12/20/90
Tel: (805) 326-0173

Appearance on this list is not to be construed as an endorsement by any regulatory agency nor is it any guarantee of the performance of the method or equipment.
Equipment should be installed and operated in accordance with all applicable laws and regulations.
For full details, please refer to our expanded "DISCLAIMER" page.