Franklin Fueling Systems Tank Sentinel (TS-1001, 2001, 504, 508 & 750) Operators Guide Rev. D - Manual (Page 70)

4 Page 4 - 4 Tank Sentinel Operator’s Guide
Reasons Why Tank Leak Tests Fail (Continued... )
• Large changes in product temperature (from start to end of the test).
• Water Level changes (from start to end of the test).
• Evaporation and loss of product – through the vent stack – will look exactly like a leak.
Evaporation can be a problem during high seasonal temperatures and/or high winds, &
when liquid level exposes the greatest surface area for evaporation (half full tanks are
worse). Seasonal variations in product composition, size of the tank (larger is worse), and
tank vent configuration are also evaporation factors.
• Tank Deformation (the tank changes shape after a large product delivery)
• Tidal Action in coastal communities may affect groundwater level and is another
source of tank deformation (certain times of the day – tide change inconsistently).
• Tank Cross-Talk – level changes in one tank causes a level change in adjacent
tank or compartment.
• Product Dispensing during a test
• Actual Tank Leaks
When a Leak Test Fails
Leak tests do occasionally fail. A single failed leak test should not be a cause for great
alarm – don’t panic. Remember, if the confidence level of the test is 99%, there is a 1%
chance that the system will give a false answer.
Don’t excavate / repair a tank because of a single failed leak test. Reference the policy
and procedures at you site / Chapter 5.
If you fail a leak test, review the leak test report to determine if there is an obvious
source of interference with the test
(see the Causes of Leak Test Failures, and Chapter
4 for an example of a Tank Leak Test Report) . If such a source of interference is identified,
retest the tank as soon as possible. (Retest the tank to validate or invalidate the first
test result if no source of interference can be identified. If necessary, run several tests.)
If repeated tests indicate a leak and no obvious source of interference is found then
immediately have the tank precision / pressure tested. If the precision test confirms
the presence of a leak then you (the tank owner) must take corrective action in
accordance with federal, state and local regulations.
NOTE
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