1. Tank Leak Detection
Alaska
Spring 2004

2. Leak Detection Orientation Basics Automatic Tank Gauging
Interstitial Monitoring
Inventory Control/TTT
SIR
Other methods

4. Good intentions

5. Orientation What do you have or use?
What does your leak detection system do?
Volumetric test
Inventory
Statistical
Presence/absence of something
Can you prove it is working properly?
Do you check your results periodically?

6. Basics Must check for evidence of leaks every 30 days
Checking/testing equipment must be maintained
Equipment/method must be 3rd party evaluated and on the List of Leak Detection Evaluations for Storage Tank Systems by the National Work Group on Leak Detection Evaluations (NWGLDE)
Must keep records of leak tests
2 months of Inconclusive/Invalid readings is a suspected release

7. Keep paper in the roll

8. Automatic Tank Gauge Most common method in Alaska
Can run test when you want
Daily, weekly, monthly, continuously
Device must be 3rd party evaluated and on NWGLDE list.
Console and probes must be checked
Keep a copy of all printouts

9. ATG Common problems Not enough fuel in tank during test
Test interrupted (fuel dispensed/delivered)
Test gets disabled
Paper/ink out
Probes go bad
Too much throughput, not enough quiet time
Older models had limits

11. Interstitial Monitoring
Double wall tanks
Interstice is space between inner and outer wall
Check the space electronically (sensor and console) or manually (stick and chart)
Electronic sensors must be on the NWGLDE list
Must check every 30 days
Must record results MONTHLY- examples Veeder-Root “Sensor Status Report”; EBW “Contact Report”; Incon “Line Compliance Report” or hand written log if display only (no printer)

12. Inventory Control & TTT
Stick tank every operational day
Reconcile daily
Track deliveries
Reconcile monthly
Calculate “leak” rate
Have a tank tightness test every 5 years.
State certified tester with current vendor certification
Test method on the NWGLDE list

13. Statistical Inventory Reconciliation
Take monthly inventory and have it analyzed by statistical company
A more sophisticated inventory control program
Gives you pass, fail or inconclusive
Statistical company method must be on the NWGLDE list

14. Bottom line
An operator must be able prove every 30 days his or her tank (and piping) is not leaking more than 0.2 gallons per hour (slightly less than one quart) of product.