| Certification |
Leak rate of 0.2
gph with PD = 99.9% and PFA = 0.1%.
Leak rate of 0.1 gph with PD = 99.6% and PFA = 0.4%. |
| Leak
Threshold |
0.1 gph for leak
rate of 0.2 gph.
0.05 gph for leak rate of 0.1 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 and where
specific gravity is > 0.6 and viscosity is < 1500 cp may be tested
after consultation with manufacturer. |
| Tank
Capacity |
Maximum of 15,000
gallons.
Tank must be between 50 and 95% full. |
| Waiting
Time |
Minimum of 2
hours between delivery and testing.
Minimum of 2 hours between dispensing and testing.
There must be no dispensing or delivery during waiting time. |
| Test
Period |
Minimum of 2
hours for leak rate of 0.2 gph.
Minimum of 6 hours for leak rate of 0.1 gph.
Test data are acquired and recorded by system's computer.
Leak rate is calculated from data determined to be valid by statistical
analysis.
There must be no dispensing or delivery during test. |
| Temperature |
Average for
product is determined by a minimum of 5 thermistors. |
| Water
Sensor |
Must be used to
detect water ingress.
Minimum detectable water level in the tank is 0.186 inch.
Minimum detectable water level change is 0.0048 inch. |
| Calibration |
Thermistors and
probe must be checked and, if necessary, calibrated in accordance with
manufacturer's instructions. |
| Comments |
Not evaluated
using manifolded tank systems. Therefore, this certification is only
applicable when there is a probe used in each tank and the siphon is broken
during testing.
Tests only portion of tank containing product.
As product level is lowered, leak rate in a leaking tank decreases (due to
lower head pressure).
Consistent testing at low levels could allow a leak to remain
undetected.
EPA leak detection regulations require testing of the portion of the tank
system which routinely contains product. |
