Issue
Date: November 22, 1995
Revision Date: July 23, 2003
Phoenix
Technologies Division of Phoenix Group
(originally listed as Arizona Instrument Corp. and NESCO)
Encompass
USF IPAM #17-901
(Ultrasonic Probe #17-9100)
AUTOMATIC
TANK GAUGING METHOD
|
Certification
|
Leak
rate of 0.2 gph with PD = 99.94% and PFA = 2.06%.
|
|
Leak
Threshold
|
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 may be tested after consultation with the manufacturer.
|
|
Tank
Capacity
|
Maximum
of 15,000 gallons.
Tank must be between 50 and 95% full.
|
|
Waiting
Time
|
Minimum
of 3 hours between delivery and testing.
There must be no dispensing or delivery during waiting
time.
|
|
Test
Period
|
Minimum
of 6 hours.
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 obtained by a single temperature sensor
that measures change in ultrasonic wave velocity.
|
|
Water
Sensor
|
Must
be used to detect water ingress.
Minimum detectable water level in the tank is 1.86 inches.
Minimum detectable change in water level is 0.012 inch.
|
|
Calibration
|
Temperature
sensor 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.
Encompass software provides for remote access capabilities.
California regulations
require at least one test per month after routine product
delivery or when the tank is filled to within 10% of
the highest operating level of previous month.
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