U1 UST Installation/Retrofitting
UST Installation Testing Requirements and
Cathodic Coatings Exam Guide 2025
Preinstallation Single-walled tank Testing (Sec. 3.2)
(Before placing components in Excavation) -Correct Answer ✔Visual Inspection
for damage or holes
3 to 5 psig air/soap test
3 psig for 12 ft diameter or greater tanks
According to manufacturer's instructions
Single-walled storage tank Testing
Before Placing the System in Service -Correct Answer ✔Tightness-test tank and
piping
Preinstallation Double-walled tank testing (Sec 3.3, 3.5-7)
(Before placing components in Excavation) -Correct Answer ✔Inspection
Max of 5 psig air/soap test for one hour
-Seal inner tank and disconnect external air supply
-Pressurize interstice with air from the inner tank, measure interstice pressure with
a third gauge
-Soap and watch for bubbles or drop of pressure on the gauges
-First release pressure in interstice, then primary tank
Preinstallation Double-walled Tank with liquid-filled interstice Testing -Correct
Answer ✔Carefully inspect interior and exterior surfaces of tank for signs of
leakage.
Check level of liquid in the interstice reservoir
Preinstallation Double-walled Tank with Vacuum on interstice Testing -Correct
Answer ✔Check to make sure the vacuum level in the interstice is within the limits
designated by the manufacturer
Double-walled storage tank Testing (Sec 3.6-7)
Before Placing the System in Service -Correct Answer ✔Inspect tank interstice or
check vacuum or liquid level
Preinstallation Testing of Compartmented Tanks
U1 UST Installation/Retrofitting
, U1 UST Installation/Retrofitting
Single-walled bulkheads -Correct Answer ✔Test compartments on different sides
of the same bulkhead at different times
Preinstallation Testing of Compartmented Tanks
Double-walled bulkheads -Correct Answer ✔Compartments may be tested at the
same time
Tank deflection Inspection (Sec 5.9)
After Assembly but before Backfilling -Correct Answer ✔Measure tank diameter
before and after installing anchor straps.
Acceptable deflection is established by the manufactorer
Tank shell deflection Testing
Before Placing the System in Service -Correct Answer ✔Compare before/after
backfilling vertical diameter. If measurements differ, consult manufacturer's
instructions for allowable variation
Tank deflection is caused by -Correct Answer ✔Inadequate support or over-
tightening of anchor straps
-Improper bedding
-Voids in the backfill under the tank-bottom quadrant
-Poor compaction of the backfill material at the tank sides
-Improper installation of anchor straps
Slope of excavation walls is determined by: -Correct Answer ✔Soil conditions
Depth of the excavation
Shoring requirements
Safety considerations
Excavation clearance 45" factor -Correct Answer ✔A straight line at a 45 degree
angle from the bottom of the tank tangentially to the side will meet a horizontal
line that is 5 ft long extending from the base of the nearby foundation
Filter fabrics are installed between:
This is to prevent the backfill from migrating and diminishing the support of the
tank or paving -Correct Answer ✔Backfill and adjacent unstable soils, bogs,
swampy areas, or landfills.
Separate dissimilar backfill materials with filter fabric to prevent mixing
U1 UST Installation/Retrofitting
UST Installation Testing Requirements and
Cathodic Coatings Exam Guide 2025
Preinstallation Single-walled tank Testing (Sec. 3.2)
(Before placing components in Excavation) -Correct Answer ✔Visual Inspection
for damage or holes
3 to 5 psig air/soap test
3 psig for 12 ft diameter or greater tanks
According to manufacturer's instructions
Single-walled storage tank Testing
Before Placing the System in Service -Correct Answer ✔Tightness-test tank and
piping
Preinstallation Double-walled tank testing (Sec 3.3, 3.5-7)
(Before placing components in Excavation) -Correct Answer ✔Inspection
Max of 5 psig air/soap test for one hour
-Seal inner tank and disconnect external air supply
-Pressurize interstice with air from the inner tank, measure interstice pressure with
a third gauge
-Soap and watch for bubbles or drop of pressure on the gauges
-First release pressure in interstice, then primary tank
Preinstallation Double-walled Tank with liquid-filled interstice Testing -Correct
Answer ✔Carefully inspect interior and exterior surfaces of tank for signs of
leakage.
Check level of liquid in the interstice reservoir
Preinstallation Double-walled Tank with Vacuum on interstice Testing -Correct
Answer ✔Check to make sure the vacuum level in the interstice is within the limits
designated by the manufacturer
Double-walled storage tank Testing (Sec 3.6-7)
Before Placing the System in Service -Correct Answer ✔Inspect tank interstice or
check vacuum or liquid level
Preinstallation Testing of Compartmented Tanks
U1 UST Installation/Retrofitting
, U1 UST Installation/Retrofitting
Single-walled bulkheads -Correct Answer ✔Test compartments on different sides
of the same bulkhead at different times
Preinstallation Testing of Compartmented Tanks
Double-walled bulkheads -Correct Answer ✔Compartments may be tested at the
same time
Tank deflection Inspection (Sec 5.9)
After Assembly but before Backfilling -Correct Answer ✔Measure tank diameter
before and after installing anchor straps.
Acceptable deflection is established by the manufactorer
Tank shell deflection Testing
Before Placing the System in Service -Correct Answer ✔Compare before/after
backfilling vertical diameter. If measurements differ, consult manufacturer's
instructions for allowable variation
Tank deflection is caused by -Correct Answer ✔Inadequate support or over-
tightening of anchor straps
-Improper bedding
-Voids in the backfill under the tank-bottom quadrant
-Poor compaction of the backfill material at the tank sides
-Improper installation of anchor straps
Slope of excavation walls is determined by: -Correct Answer ✔Soil conditions
Depth of the excavation
Shoring requirements
Safety considerations
Excavation clearance 45" factor -Correct Answer ✔A straight line at a 45 degree
angle from the bottom of the tank tangentially to the side will meet a horizontal
line that is 5 ft long extending from the base of the nearby foundation
Filter fabrics are installed between:
This is to prevent the backfill from migrating and diminishing the support of the
tank or paving -Correct Answer ✔Backfill and adjacent unstable soils, bogs,
swampy areas, or landfills.
Separate dissimilar backfill materials with filter fabric to prevent mixing
U1 UST Installation/Retrofitting
