UST Certification Study Guide

When tanks arrive at the job site, how should they be unloaded?

Lifted off with a cable attached to the tank lifting lugs.

As an alternative lifting method, should a cable or chain be wrapped around the tank?

No, Never.

When you are lifting a tank, using the lifting lugs, which of these procedures should be followed?

Attach a triangle cable through the lugs, with not more than a 30-degree angle from the center line.

After you unload a new tank on a clean, level surface at the job site, what else would you do prior to inspection and pretesting?

Chock the tank to prevent it from rolling.

Which of the following items should be physically check for damage or imperfections at the job site?

- Piping (steel and fiberglass).

- Fittings, vents, fill-boxes, anodes, etc.

- The tanks themselves.

Sti-P3 tanks are delivered with shipping plugs in tank openings. What should be done to these plugs prior to testing?

Remove the plugs and replace them with standard threaded plugs, properly doped.

Should dielectric bushings be installed in all openings of a sti-P3 tank?

Yes. All openings.

What is the maximum air pressure to which a steel tank should be subjected in a pre-installation test?

5 Pounds

For fiberglass reinforced plastic (FPR) tanks, up to 12 feet in diameter, what is an acceptable air pressure to which the tanks may be subjected in a pre-installation test?

3 Pounds

For FRP tanks over 12 feet in diameter, what is the maximum air pressure to which the tanks should be subjected in a pre-installation test?

3 Pounds

When you are conducting an air test on a tank, the type of gauge that should be used is...?

A pressure gauge with a maximum limit of 10-15 psig.

When conducting a pre-installation air test on a new single wall tank...

Soap the surface of the tank and observe any air bubbles in the soap.

The proper procedure for conducting a pre-installation air test of a steel tank is to...

Apply 3 to 5 pounds of air pressure and soap all surfaces and weld seams visible through the coating, while inspecting for bubbles.

The proper procedure for conducting a pre-installation air test of an FRP tank, under 12 feet in diameter, is to...

Apply 3 pounds of air pressure and soap all surfaces, while inspecting for any sign of a leak, either audible or visible in the form of bubbles on the surface.

The proper procedure for conducting a pre-installation air test of a double-walled tank is to...

Pressurize the inner tank, monitor the pressure for 1 hour, and then pressurize the space between the inner and outer tanks with air from the inner tank.

When conducting a pre-installation air test on a double-walled tank, which of the following is correct?

Release pressure on the outer tank (interstice) first, then release the pressure on the inner tank, after the test is completed.

When shipped, a steel tank is covered with a coating that is an important part of the tank's corrosion prevention system. "Holidays" which show up in the coating at the installation site...

Should be touched up with a compatible coating, after proper surface preparation.

Touch up of "holidays" in steel tank coatings, at the installation site, should be done...

According to the manufacturer's instructions.

Dielectric bushings are usually made of...

Nonmetallic material.

Factors to consider in determining the size, shape, and depth of a tank excavation include...

- The tank manufacturer's recommendations.

- Requirements for compacting bedding and backfill, as well as stability of the soil.

- Depth of cover.

In the absence of local requirements, the recommended minimum distance between a tank excavation and adjacent structures or property lines is

5 feet.

Reinforcement of a steel underground tank may be required by the tank manufacturer if...

The burial depth is greater than the tank diameter.

According to FRP tank manufacturers' specifications, the burial depth for an FRP tank should not exceed...

7 feet.

Ballast, whether water or fuel, should be added to the tank at what stage of the installation?

After the tank has been backfilled to the top of the tank.

When installing a cathodically protected steel tank, you should..

Make sure the excavation is free from material that could cause damage to the coating.

When installing dielectric bushings in a cathodically protected steel tank, before placing the tank in the excavation...

Make sure that no electric current can pass through the dielectric flanges or bushings.

Acceptable bedding materials for steel tanks include...

- Clean, washed, well-granulated gravel, sand or rock between 1/8 and 1/2 inch in size.

- Pea gravel, with a minimum diameter of 1/8 and a maximum of 3/4 inch.

- No. 8 crushed stone

Steel tanks should be lowered into the excavation...

Through the use of lifting lugs, installed by the manufacturer, and use of lifting equipment of sufficient capacity to lift and lower the tank.

When installing a steel tank which has zinc anodes welded directly onto the tank for cathodic protection, you should...

Remove the plastic wrappings around the anodes prior to installation.

In making a tank excavation, if you discover that the specifications call for the burial depth of the steel tank to be greater than the tank diameter, what should you do?

Consult the tank manufacturer to determine of reinforcement will be required.

What is the minimum depth of bedding required for a pipe trench in traffic areas?

6 inches.

Measured from the finish grade, what is the minimum burial depth for the piping system of a tank in traffic areas?

18 inches.

In planning your trenches for the piping system, how much slope, toward the tank, should be allowed for each linear foot of piping?

1/8 inch.

Excessive deflection of an installed tank, particularly tanks made of fiberglass reinforced plastic, can create residual stress on the tank. After you have measured the amount of deflection in a tank you have just installed, how do you determine if the deflection is acceptable?

Check with the tank manufacturer if the actual deflection exceeds the limits established by that manufacturer.

What is the major cause of deflection in a newly installed tank?

Improper bedding, voids under the tank bottom, and poor compaction of backfill material.

If both pea gravel and sand are used as backfill in the same excavation, what material should be used to prevent migration of sand fines into voids in the pea gravel?

Filter fabric

If a bottom hold-down pad is used, as a means of anchoring the tank, what is the minimum distance the pad should extend beyond the sides and ends of the tank?

18 inches beyond each side, 12 inches beyond each end.

When installing a bottom hold-down pad, what should be the proximity of the tank to the hold-down pad?

An adequate bedding of backfill material must separate the tank and the pad.

For purposes of making tank anchorage calculations, what is the approximate weight of one cubic foot of sand or pea gravel?

60 pounds.

What are Deadmen anchors?

Beams of reinforced concrete, placed in the excavation with cables and/or straps attached.

In dry areas, where tank flotation is not a problem, and which are not subject to traffic, what is the minimum depth of cover recommended?

One foot of backfill material plus four inches of reinforced concrete OR One foot of backfill covered by filter fabric and one foot of earth.

For steel, FRP and Composite (FRP-clad) tanks, the bottom of the excavation should be covered with a bedding of backfill material to a depth of at least...

1 foot.

If a hold-down pad is used in the bottom of the excavation, the bedding may be reduced to a depth of...

6 inches.

Native soil may be used as a backfill for tanks when...

Never. Native soil is unacceptable as a backfill material.

The preferred backfill material for fiberglass reinforced plastic tanks is...

pea gravel, with a minimum diameter of 1/8 inch and a maximum of 3/4 inch.

The recommended backfill material for steel or composite (fiberglass-clad) steel tanks may be what materials.

Sand, pea grave, crushed rock

Compaction of bedding and backfill materials is essential for this reason...

Compaction insures proper support of the tank and prevents its movement or settlement.

A filter fabric should be installed between the backfill and adjacent unstable soins, bogs, swampy areas, or landfills to...

Prevent the backfill from migrating and thus diminishing support of the tank or paving.

If sand and pea gravel are used in the same excavation, they should be separated with filter fabric in order to...

Prevent sand fines from migrating into the voids between pea gravel particles.

One problem with the use of filter fabrics, which the tank installer should always be aware of, is that a filter fabric placed in the excavation can...

Mask early signs of a cave-in during construction operations.

Careful and complete compaction of backfill is particularly critical for the...

Lower quadrant of the tank.

After back-filling is complete to the top of an FRP tank, and piping is about to begin, what action should be taken with respect to the tank?

The tank diameter should be carefully measured to determine if any deflection has occurred.

In areas of impervious soils, anchoring to prevent tank flotation might be required due to the "bathtub effect" caused by...

Infiltration of surface water into the tank backfill, causing a locally high water table around the tank.

When concrete deadmen are used to mechanically anchor a tank, they should...

Be placed outside the tank diameter.

When a bottom hold-down pad is used to mechanically anchor a tank...

The thickness of the pad, and the number and size of the anchors, should be calculated for each installation.

When a bottom hold-down pad is used to mechanically anchor a steel underground tank...

The tank and the pad should be separated by appropriate backfill material.

Under normal conditions, the backfill and paving on top of the tank will provide adequate restraint, and make mechanical anchoring unnecessary, if the burial depth is at least what percentage of the diameter of the tank?

60%

According to specifications issued by FRP tank manufacturers, hold-down straps used for anchoring FRP tanks should...

Be positioned according to recommendations of the manufacturer.

When using a hold-down concrete pad to anchor a cathodically protected steel tank...

Hold-down straps should be separated from the tank with an inert insulating dielectric material.

Anchoring of underground storage tanks is required when...

A high water table exists or if site flooding can be expected.

Secondary containment devices used in underground storage systems are designed to serve a variety of purposes. Some purposes are...

- To contain any discharge from the tanks or piping.

- To make it easier to detect a discharge from the tanks or piping.

- To provide a convenient means of recovering released product.

In a double-walled tank, the area between the inner tank and the outer tank is generally referred to as...

The interstice, or interstitial space.

Which devices are considered to be a method for achieving secondary containment?

- Double-wall tank.

- Double-wall piping.

- Impervious synthetic membrane liner.

When an impervious synthetic membrane liner is used to line the walls and bottom of a tank excavation, and an observation well is specified for the installation, the observation well should be located...

Inside the tank-hole liner.

When used as a tank-hole excavation liner, an impervious synthetic membrane liner should be pitched to a sump in the excavation in order to...

To provide a collection point for detection and removal of any product release that may occur.

Piping trench liners should be...

Sloped toward a collection point within the lined area to facilitate detection of leaked product.

What are some methods suitable for preventing releases due to overfilling underground storage tanks?

- Fillpipe enclosures, or catchment basins, located around the tank fill opening.

- Vent float valves that slow delivery rates when the maximum desirable tank capacity is reached.

- High level sensors that sound an alarm or interrupt delivery when a predetermined liquid level has been achieved.

If a vent float valve is used to reduce the likelihood of tank overfilling, precautions must be taken to prevent...

Over-pressurization of the tank.

To prevent spilling associated with product transfer to the UST system, owners and operators must use the following...

A spill catchment basin.

A line-pressure leak monitoring device, located in the piping system between the tanks and dispensers, is effective only if used in conjunction with...

Submersible (or remote) pumps.

A line-pressure leak monitoring device has the capability of causing all of the following to occur.

- A slow-down in the pumping rate.

- Interruption of electric power to the pumps.

- Actuation of an audible alarm or illuminated signal.

On a suction system, with one check valve located under the pump, the following methods of leak detection for piping must be used...

No other method of leak detection for piping is required.

Methods for monitoring the interstice in double-walled tanks include the following...

- Sensors to detect the presence of vapors in the interstice.

- Sensors to detect the presence of the stored liquid in the interstice.

- Sensors to detect pressure changes in the interstice.

To be effective, observation wells installed in conjunction with underground tank systems should extend below the bottom of the tanks by not less than...

2 feet.

Access covers used on wells at tank storage sites should be clearly marked and identified, mainly to...

Prevent delivery vehicle drivers from mistaking them for tank fill openings, and pumping product into the wells.

Observation wells can be equipped with continuous electronic monitoring devices which convey a signal to a remote point indicating the presence in the well of...

Spilled or leaked product and vapors.

Observation wells are perforated or slotted, and may be made of the following materials...

- PVC.

- Coated steel pipe.

- Galvanized steel pipe.

The following answer includes methods of leak detection for underground tanks approved by the EPA...

Vapor Monitoring wells, Groundwater Monitoring Wells, Automatic Tank Gauge, Monitoring the interstice between the walls of a double wall tank.

The difference between a Vapor Monitoring well and a groundwater monitoring well is...

The construction and placement of the wells are basically the same. If the well contains ground water, the well is sampled with a bailer sampler, if the well has no water, it is sampled with a "sniffer" or photoionization meter.

What are methods acceptable of leak detection of UST tanks?

- Monthly inventory control and tank tightness testing.

- Automatic tank gauging.

- Vapor monitoring.

Manual tank gauging should be performed...

By taking two fuel depth readings at least 36 hours apart and comparing the two readings for losses.

Groundwater monitoring wells should be...

Installed within or immediately below the UST system excavation zone.

Tank tightness testing...

Must be capable of detecting a 0.1 gallon per hour leak rate from any portion of the tank that routinely contains product.

Installation of steel pipe unions underground is...

Not recommended, but if use is unavoidable, the unions should be 250/300 pound unions with metal seats.

When planning the piping layout for an underground tank installation...

Piping runs across tanks should be held to a minimum.

Threaded steel piping for underground use should...

Be threaded with sharp cutting dies to assure proper threads and tight joints.

In a cathodically protected steel underground piping system, components such as dispensers, submerged pumps, and tanks, which you do not intend to be protected by the cathodic protection system for the piping, should be...

Electrically isolated from the piping.

If buried, metallic pipe and fittings used to connect non-metallic piping to components of the tank storage system should...

Be coated or wrapped and cathodically protected.

When two or more tanks are interconnected through a siphon connection, it is recommended that they should...

Be of the same diameter, contain the same type of product and be buried at the same elevation.

Vent piping connected to underground tanks...

Must Have a discharge point upward which is not less than 12 feet above adjacent ground or 2 feet above the roof at the point of attachment, if attached to a building.

Couplings and fittings used in the piping of a steel underground petroleum product storage system should be at least...

150 pound malleable iron.

Between all underground lines and the excavation sides, top and floor, there should be...

A minimum of 6 inches of well compacted approved backfill material.

Underground product lines and vapor return lines (if required) for petroleum storage systems should...

Have a uniform slope of not less than 1/8 of an inch per foot toward the tank.

Flex joints should be installed on metallic underground petroleum system piping...

At points where the piping connects with the underground tanks and where it ends at pump islands and vent risers.

Suction and fill lines should be installed...

At least 4 inches from the tank bottom.

An air pressure tightness test, conducted on a newly installed product piping system before the system is covered or placed in use, should...

Be conducted by pressurizing the piping system at 50 psig for a period of 1 hour, soaping all joints and inspecting for bubbles.

To minimize possible problems resulting from cracked fittings or sand holes in fittings, as well as corrosion of fittings, it is recommended that...

All metal fittings used in piping systems be of extra heavy quality.

Although new piping should be tested with air pressure, if for some reason piping has been backfilled or has contained product prior to testing, then a hydrostatic test should be conducted. The proper pressure for a hydrostatic test of piping is...

110% of operating pressure, but not less than 50 psig

Before being covered, new piping, except for the fill pipe, should be subjected to an air test for a period of not less than...

1 hour.

When preparing a new piping system for an air test, you should first isolate the product lines from...

Both tanks and dispensers.