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Issue Date: November 22, 1995
Revision Date: November 6, 1997
Leak Detection
Systems, Inc.
Tank Auditor,
Version RTD V.2.16
VOLUMETRIC TANK TIGHTNESS TEST
METHOD (OVERFILL)
| Certification |
Leak rate of 0.1
gph with PD = 99.98% and PFA = 0.02%. |
| 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, except as noted
below.
If using two level testing, the level is changed by 3 feet between the two
tests and a tank system should not be declared tight if the net change
between the two tests is greater than 0.02 gph. |
| Applicability |
Gasoline, diesel,
aviation fuel, fuel oil #4.
|
| Tank
Capacity |
Maximum of 15,000
gallons.
Tank must be minimum 100% full. |
| Waiting
Time |
Minimum is
variable depending on site conditions, but not be less than 6 hours
between delivery and testing.
Minimum of 1 hour between "topping off" and testing.
There must be no 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 to be valid by statistical
analysis.
There must be no dispensing or delivery during test. |
| Temperature |
Average for
product is determined by a temperature averaging probe. |
| Groundwater |
If depth to
groundwater cannot be determined, two tests must be performed with a level
change of at least 3 feet between tests.
If depth to groundwater in tank excavation backfill can be determined and
it is above bottom of the tank, product level must be adjusted to provide
height differential of 3 feet between product and groundwater in tank
excavation backfill during test. |
| Calibration |
Temperature
averaging probe and level sensors must be calibrated in accordance with
manufacturer's instructions before each test. |
| Comments |
Not evaluated
using manifolded tank systems.
Evaluation of system did not include a field evaluation of groundwater
compensation by two level testing. |
|
Leak Detection Systems,
Inc.
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Evaluator:
Ken Wilcox Associates
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106 Longwater Dr.
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Tel: (816) 443-2494
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Norwell, MA 02061
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Date of Evaluation:
11/29/91
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Tel:
(617) 878-7766
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