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Issue Date: April 18, 1997
Revision Date: September 11, 1998
Tidel
Engineering, Inc.
Tidel
Environmental Monitoring System, 3500 Series
(Ultrasonic Probes #401-0009, #401-0010, #401-0023)
AUTOMATIC TANK GAUGING METHOD
| Certification |
Leak rate of 0.2
gph with PD = 95.3% and PFA = 4.7% for 2 hour test.
Leak rate of 0.2 gph with PD = 99.5% and PFA = 0.5% for 4 hour test. |
| 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. |
| Tank
Capacity |
Maximum of 15,000
gallons.
Tank must be between 50 and 95% full. |
| Waiting
Time |
Minimum of 2
hours, 29 minutes between delivery and testing.
Minimum of 15 minutes after dispensing.
There must be no delivery during waiting time. |
| Test
Period |
Minimum of 2
hours to achieve PD = 98.6% and PFA = 1.4%.
Minimum of 4 hours to achieve PD = 99.5% and PFA = 0.5%.
Test data are acquired and recorded by the microprocessor contained within
the EMS console.
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 from the measurement of the change in the speed of
sound. |
| Water
Sensor |
Must be used to
detect water ingress.
Minimum detectable water level in the tank is 1.48 inches.
Minimum detectable water level change is 0.035 inch. |
| Calibration |
Temperature
sensors and ultrasonic 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.
The water sensor,
temperature sensor, and product level monitor are contained in a single
ultrasonic probe. 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. |
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Tidel Engineering, Inc.
|
Evaluator:
Ken Wilcox Associates
|
|
2025 West Beltline Road, #114 |
Tel:
(816) 443-2494
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|
Carrollton
,
TX 75006
|
Date of Evaluation:
03/16/95
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Tel:
(800) 678-7577
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