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Issue Date: August 23, 1999
Revision Date: January 24, 2008
Steel Tank Institute
Permatank Interstitial Vacuum
Monitor Liquid Leaks
INTERSTITIAL TANK TIGHTNESS TEST METHOD
| Certification |
Leak rate of 0.1
gph with PD = 100% and PFA < 5%. |
| Leak
Threshold |
A tank system
should not be declared tight when the vacuum decreases (pressure
increases) 5 inches or more of mercury over the test period specified for
each tank size.
Vacuum prior to test must be minimum of 14 inches of mercury. |
| Applicability |
Gasoline, diesel,
water. |
| Tank
Capacity |
Maximum of 20,000
gallons. No minimum product level during test. |
| Waiting
Time |
None between
delivery and testing. |
| Test
Period |
Test periods
required for selected tank sizes to detect a leak rate of 0.1 gph |
|
Selected
Tank Sizes
|
gasoline
|
diesel
|
water
|
|
500
gal
|
0.4
hr
|
5.0
hr
|
4.8
hr
|
|
5,000
gal
|
1.3
hr
|
16.2
hr
|
15.7
hr
|
|
8,000
gal
|
2.1
hr
|
24.9
hr
|
24.2
hr
|
|
20,000
gal
|
3.7
hr
|
44.8
hr
|
43.6
hr
|
|
Comments
|
System tests the interstitial space between inner steel wall
and outer fiberglass wall of Steel Tank Institute's Permatank.
System detects breaches in either inner or outer tank walls.
System can perform tank tightness testing of Steel Tank Institute's double wall
Permatank after product has been added to the primary tank.
System was not evaluated for ability to detect layer of hydrocarbons on water.
Evaluation did not cover any liquid sensors.
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Steel Tank Institute
|
Evaluator:
Ken Wilcox Associates
|
|
570 Oakwood Rd.
|
Tel: (816) 443-2494
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Lake Zurich, IL 60047
|
Date of Evaluation:
04/24/94
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Tel: (847) 438-8265
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