| Certification |
Leak rate of 0.1
gph with PD = 99.5% and PFA = 0.5%. |
| 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.
|
| Tank
Capacity |
Maximum of 18,000
gallons.
Tank must be between 92 and 100% full. |
| Waiting
Time |
Minimum of 12
hours between delivery and testing.
Minimum of 3 hours between "topping off" and testing.
There must be no product dispensing or delivery during waiting time. |
| Test
Period |
Minimum of 1
hour.
Test data are acquired and recorded by system's computer. Leak rate is
calculated from data determined valid by statistical analysis.
There must be no dispensing or delivery during test. |
| Temperature |
Average for
product is determined by a minimum of 6 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 net pressure of 2-4 psi on bottom of tank during test. |
| Calibration |
Level sensors
must be calibrated in accordance with manufacturer's instructions before
each test. Temperature sensors must be calibrated in accordance with
manufacturer's instructions semi-annually. |
| Comments |
Not evaluated
using manifolded tank systems.
Tests only portion of tank containing product. |
