|
Issue Date: August 9, 2001
Revision Date: December
21, 2005
Varec, Inc.
(originally
listed as Coggins Systems, Inc. and later as Endress + Hauser Systems and
Gauging)
FuelsManager
and Remote Terminal Unit RTU/8130
(MTS Magnetostrictive Probe)
BULK UNDERGROUND STORAGE TANK
LEAK DETECTION METHOD (50,000 gallons or greater)
| Certification |
Leak rate is
proportional to product surface area (PSA).
For tanks with PSA of 616 ft², leak rate is 0.2 gph with PD = 96.4% and
PFA = 3.6%
For other tank sizes, leak rate equals [(PSA in ft² ÷ 616 ft²) x 0.2
gph].
Example:
For a tank with PSA = 900 ft²; leak rate = [(900 ft² ÷ 616 ft²) x 0.2
gph] = 0.29 gph.
Leak rate may not be scaled below 0.2 gph. |
| Leak
Threshold |
Leak threshold is
proportional to product surface area (PSA). For tanks with PSA of 616
ft², leak threshold is 0.1 gph.
For other tank sizes, leak threshold
equals [(PSA in ft² ÷ 616 ft²) x 0.1 gph].
Example:
For a tank with PSA = 900 ft²; leak threshold = [(900 ft² ÷ 616ft²) x
0.1 gph] = 0.1gph.
A tank system should not be declared tight if the test result indicates a
loss or gain that equals or exceeds the calculated leak threshold. |
| Applicability |
Gasoline, diesel,
aviation fuel. |
| Tank
Capacity |
Use limited to
single field-constructed vertical tanks 50,000 gallons or greater.
Maximum product surface area (PSA) is 924 ft².
Product must be at full
operating level. |
| Waiting
Time |
Minimum of 4
hours, 26 minutes after delivery or dispensing. |
| Test
Period |
Minimum of 24
hours.
There must be no dispensing or delivery during test. |
| Temperature |
Average for
product is determined by a minimum of 5 resistance temperature detectors (RTDs).
Product temperature change during test should not exceed 0.72 degrees F. |
| Water
Sensor |
Must be used to
detect water ingress. Minimum detectable water level in the tank is 0.238
inch.
Minimum detectable change in water level is 0.0017 inch. |
| Calibration |
Probe must be
checked and, if necessary, calibrated in accordance with manufacturer's
instructions. |
| Comments |
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.
FuelsManager uses PC-based software to process probe data.
Remote Terminal Unit (RTU/8130) contains software embedded in a CPU housed
in a stand-alone console.
Evaluated in a nominal 50,000 gallon vertical
underground tank with product surface area (PSA) of 616 ft².
The maximum product level in the tank during test was 65% (32,500
gallons). |
|
Varec,
Inc.
|
Evaluator:
Ken Wilcox Associates
|
|
5834 Peachtree Corners East
|
Tel: (816) 443-2494
|
|
Norcross, GA 30092
|
Date of Evaluation:
11/24/98
|
|
Tel: (770) 447-9202
|
|
|
