This document discusses requirements and procedures for line tightness and leak detector testing of underground storage tank systems in Tennessee. Key points include:
- Line tightness tests must detect a 0.1 GPH release and are required annually for pressurized piping unless monthly monitoring is used.
- Proper procedures are outlined for conducting line tightness tests using equipment such as the Petro-Tite line tightness tester and interpreting potential issues indicated by pressure and volume changes.
- Mechanical and electronic line leak detectors must be tested to simulate a 3.0 GPH leak to verify operability. The Petro-Tite system can be used to conduct this test on mechanical line leak detectors.
Lessons learned solving pilot valve instability issues on LNG storage tanks
pressurized piping LLD testing chattanooga 2015
1. Line Tightness and Leak Detector Testing
Petro-Tite Line Tightness Tester
July 15, 2015
Chattanooga, Tennessee
2. Line Tightness Test Requirements
Tennessee UST Regulations
•Must detect 0.1 GPH release at 1 ½ times operating pressure
•Required by rule at installation; Rule 400-18-01-.02(1)(d)6.
•Results must be maintained until next test; Rule 400-18-01-.04(5)(b)
•Required annually for pressurized piping; Rule 400-18-01-.04(2)(b)1.
– Unless site is using monthly monitoring (interstitial monitoring, SIR, electronic
LLD)
3. Terminology- Pressurized Piping
• Full Pump Pressure
• LLD Holding Pressure
• LLD Metering Pressure
• LLD Opening Time
• Maximum Allowable Bleedback
• Leak Rate in Gallons per Hour
14. Preparing to Test
Site Safety Meeting
Deactivate sub pump (SAFETY FIRST)
Connect to line- shear valve at furthest
dispenser
No ball valve- use “silver bullet”
15. Site Safety
STP relay stuck in
ON position
ALWAYS
DEACTIVATE STP
at the electrical
panel !
16. Site Safety cont.
• STP Sumps >4 feet deep (ingress)
• Gasoline Vapors- flammable AND TOXIC
• Displaced oxygen
• Motor Vehicles/Pedestrians
• Cones/Barricades
• PPE- Gloves, vest, glasses, boots
• Partner always recommended
17. Preparing to Test
• REMOVE LEAK DETECTOR and connect
at the STP when :
– No in-line ball valve present at STP
– Confirming STP leaking into tank (o-rings,
check valve or functional element)
– Testing large or long flex lines
– Bad fittings at shear valve
18. Common Line Testing Problems
• Bad Functional Element- leaks into tank
• NO BALL VALVE- must test at the tank.
• Satellite Dispensers
• Air/Vapor Pockets
• Piping Deflection (flex pipe)
• Liquid/Vapors in STP sump
19. Example 1- Temperature Change
o Large Pressure Changes
o Small Volume Changes
o Diminishes to “0” PSI
o SOLUTION- obtain 2-3 readings w/no change; can be prevented by
purging line prior to test.
Time
(Military)
Event Description Pressure (psi) Volume (gallons)
Comments/Actions
(List leaks observed even if repairs are made and retest passes)
Before After Before After Net Change
0800 Begin Line Test 50
0815 21 50 .0850 .0810 -.0040
0830 30 50 .0810 .0780 -.0030
0845 37 50 .0780 .0755 -.0025
0900 42 50 .0755 .0735 -.0020
0915 45 50 .0735 .0720 -.0015
0930 47 50 .0720 .0710 -.0010
0945 49 50 .0710 .0705 -.0005
1000 50 50 .0705 .0705 .0000
20. Example 2- Pipe Deflection
Time
(Military)
Event Description Pressure (psi) Volume (gallons)
Comments/Actions
(List leaks observed even if repairs are made and retest passes)
Before After Before After Net Change
0940 Begin Line Test 50
0950 43 50 .0655 .0610 -.0045
1000 46 50 .0610 .0570 -.0040
1010 48 50 .0570 .0535 -.0035
1020 49 50 .0535 .0515 -.0020
1030 49.5 50 .0515 .0500 -.0015
1040 49.8 50 .0500 .0490 -.0010
1050 49.9 50 .0490 .0485 -.0005
1100 50 50 .0485 .0485 .0000
o Small Pressure Losses
o Small Volume Losses
o Diminishes to “0” PSI
o Gradual volume changes; 30 minutes-1 hours
o Solution: Conduct Beginning Bleedback Test and stretch line prior to test
21. Example 3- Air/Vapor Pocket
Time
(Military)
Event Description Pressure (psi) Volume (gallons)
Comments/Actions
(List leaks observed even if repairs are made and retest passes)
Before After Before After Net Change
1400 Begin Line Test 50
1405 46 50 .0910 .0260 -.0065 Re-filled burette
1410 45 50 .0860 .0410 -.0041 Re-filled burette
1415 46.5 50 .0770 .0070 -.0070 Re-filled burette
1420 46.0 50 .0850 .0300 -.055 Re-filled burette
o Small Pressure Changes
o Very Large Volume Changes
o Non-repeating and inconsistent
SOLUTION: End test and purge air from line; locate any potential points of
air (siphon lines, low points in product line, dead ends)
22. Example 4- High Rate of Leak
Time
(Military)
Event Description Pressure (psi) Volume (gallons)
Comments/Actions
(List leaks observed even if repairs are made and retest passes)
Before After Before After Net Change
1315 Begin Line Test 50
1320 15 50 .0750 .0200 -.0045 Re-filled burette
1325 17 50 .0830 .0260 -.0040 Re-filled burette
1330 14 50 .0910 .0330 -.0035 Re-filled burette
1335 16 50 .0780 .0220 -.0020 Re-filled burette
1340 15 50 .0870 .0320 -.0015 Re-filled burette
o Large Pressure Losses
o Large Volume Losses
o Repeated and Consistent Losses over time
o May have to speed up readings, rapid pressure changes
for large leaks
24. Mechanical Line Leak Detectors
(MLLD)
Invented in 1958 by Elmer Deter,
Red Jacket Application Engineer
Alerts operator of nozzle to low
line pressure
28. Electronic Line Leak Detectors
(ELLD)
• Tests line during idle time
• Must simulate a 3.0 GPH leak to test
• Programming must be verified
– Pressure based (Veeder-Root PLLD)
– Flow based (Franklin/OPW)
29. ELLD Testing
• Activates STP
during idle to
conduct testing
• Secondary
containment may
be required
32. Petro-Tite LLD Test
1) Connect pressure regulator
2) Energize STP, adjust pressure to
10 PSI
3) Adjust Petro-Tite flow rate to 189
ml/min (3 gallons per hour)- black
hoke valve
4) De-energize STP
5) Remove regulator and connect
piping to Petro-Tite system
33. Petro-Tite LLD Test
5) Reactivate STP; MLLD should stay in
leak test mode (1 gal/minute)
6) Keep STP running and close 3-way valve;
MLLD should close, full flow.