Issue
Date: April 17, 2002
Revision Date: January 12, 2011
USTest,
Inc.
(previously
listed as Sound Products Manufacturing, Inc.)
UST
2001/P
(Ultrasonic Probe)
VOLUMETRIC
TANK TIGHTNESS TEST METHOD (UNDERFILL)
|
Certification
|
Leak
rate of 0.1 gph with PD = 97% and PFA = 0.6%
|
|
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 may be tested after consultation with the
manufacturer.
|
|
Tank
Capacity
|
Maximum
of 20,000 gallons.
Minimum product level required is 15 inches (1 inch above lowest calibration rod).
|
|
Waiting
Time
|
Minimum
of 4 hours between delivery and testing.
There must be no dispensing or delivery during waiting
time.
|
|
Test
Period
|
Minimum of 1 hour.
There
must be no dispensing or delivery during test.
|
|
Temperature
|
Average
for product is determined by an ultrasonic probe containing
5 temperature targets.
Targets located above the product surface are not used
in data analysis.
If a test is to be conducted following a product delivery,
the temperature difference between the product in the
tank and the product delivered should not exceed 7.7 degrees
F.
|
|
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
1 psi at bottom of the tank during test.
|
|
Calibration
|
Probe
must be checked regularly and, if necessary, calibrated
in accordance with manufacturer's instructions.
|
|
Comments
|
System
consists of an ultrasonic probe which interfaces with
a micro processing unit.
Not
evaluated using manifolded tank systems.
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.
|
