API 653 CLOSED BOOK Exam 100 Questions with Verified Answers
Two methods of quantifying the remaining thickness of tank bottoms are mentioned in API
... [Show More] 653. One method uses the formula involving "MRT". What is the name of the other method?
a. Deterministic and Analytic
b. Methodological and Non-destructive
c. Quantitative and Destructive
d. Probabilistic and Deterministic - CORRECT ANSWER Probabilistic and Deterministic
What is the maximum out-of-plumbness allowed from the top of the shell to the bottom of the shell on a 48' high tank?
a. 5.76"
b. 5.00"
c. 5.48"
d. 4.80" - CORRECT ANSWER 5.00"
Due to strength requirements, the minimum thickness of an annular plate ring is usually greater than:
a. 0.187"
b. 0.125"
c. 0.100"
d. 0.250" - CORRECT ANSWER 0.100"
The joint between the new material of an insert plate and the old material of the existing tank shell plate shall be:
a. Lap welded
b. Plug welded
c. Butt welded
d. Fillet welded - CORRECT ANSWER Butt welded
A pressure test at least 1.5 times the __________ shall be performed on a nozzle installed by hot tapping after the valve has been installed on it and prior to mounting the hot tap machine.
a. Design head
b. Operating head
c. Working head
d. Hydrostatic head - CORRECT ANSWER Hydrostatic head
Cone roof storage tanks may be as large as ______ feet in diameter.
a. 100'
b. 50'
c. 300'
d. 80' - CORRECT ANSWER 300'
The simplest type of floating roof is the:
a. Pan
b. Pontoon
c. Double deck
d. Cone - CORRECT ANSWER Pan
An oxygen deficient atmosphere exists when a tank atmosphere has less than what percent oxygen by volume?
a. 18.5%
c. 15.0%
b. 19.0%
d. 19.5% - CORRECT ANSWER 19.5%
Lead-in-Air analyzers must be designed to measure _______ Lead-in-Air concentrations.
a. Organic
b. Inorganic
c. Radioactive
d. Liquid - CORRECT ANSWER Organic
Entry into a confined space is considered to have occurred as soon as:
a. Half the entrant's body is inside the confined space.
b. The entrants head enters the confined space.
c. A part of the entrant's body breaks the plane of an opening into the space.
d. The entrant's head and shoulders enters the confined space. - CORRECT ANSWER A part of the entrant's body breaks the plane of an opening into the space.
When repairs involve most of the tank bottom, it may be desirable to displace the flammable liquids beneath the tank by:
a. Purging with CO2
b. Purging with N2
c. Water flooding
d. Using an odorized gas - CORRECT ANSWER Water flooding
Tank surfaces that have been in contact with leaded gasoline should be scraped down to bare metal. On each side of a line that might be heated excessively by welding or other operations, an area of at least ______ should be scraped down to bare metal.
a. 6"
b. 24"
c. 10"
d. 12" - CORRECT ANSWER 12"
What is the axis of a weld?
a. A line drawn parallel with the base of the material.
b. A line through the center of the weld, parallel with the sides of the weld.
c. A line through the center of the weld, perpendicular with the weld.
d. A line drawn from the base to the throat of a weld - CORRECT ANSWER A line through the center of the weld, parallel with the sides of the weld
In monitoring the density limitations of radiographs, either a ________ or step wedge comparison film shall be used for judging film density.
a. Proportionometer
b. Galvanometer
c. Densitometer
d. Penetrameter - CORRECT ANSWER Densitometer
During tank roof evaluations, roof plates corroded to an average thickness of less than ______ in any 100 square inch area shall be repaired or replaced.
a. 0.06"
b. 0.12"
c. 0.10"
d. 0.09" - CORRECT ANSWER 0.09"
API 653 covers minimum requirements for maintaining the integrity of above ground storage tanks.
a. After placed in service.
b. Before
c. During construction.
d. During testing. - CORRECT ANSWER After placed in service
In the evaluation of fixed roofs for continued service, particular attention must be given to:
a. The number of columns used for a roof.
b. The size of columns vs. the roof load.
c. The possibility of internal corrosion of pipe columns.
d. The configuration of the columns and attachments. - CORRECT ANSWER The possibility of internal corrosion of pipe columns
In determining the lowest average thickness t avg (or t1) over a length of "L" of a tank shell plate, the inspector shall use at least _______ equally spaced measurements over the length of "L".
a. Three
b. Six
c. Ten
d. Five - CORRECT ANSWER Five
To determine if a tank is suitable for continued operation, t1 shall be greater than or equal to t min subject to verification of all intended loadings and the value of t2 shall be greater than or equal to what percent of t min?
a. 30%
b. 40%
c. 50%
d. 60% - CORRECT ANSWER 60%
Tanks with diameters greater than ______ feet shall be analyzed for acceptable shell plate thickness using the variable design point method in API 650.
a. 150
b. 175
c. 200
d. 250 - CORRECT ANSWER 200
In evaluating tank shell corrosion/pitting, widely scattered pits may be ignored provided that pits meet API 653 depth acceptability criteria and the length of each pitted area does not exceed __ inches in an examined length of __ inches.
a. 4,10
b. 2,8
c. 1,6
d. 5,12 - CORRECT ANSWER 2,8
Atmospheric pressure when used to describe the design pressure of a tank refers to internal pressure up to but not exceeding:
a. 2.5 ounces per in2 gage.
b. 2.5 pounds per ft2 gage.
c. 2.5 grams per cm2 gage.
d. 2.5 pounds per in2 gage. - CORRECT ANSWER 2.5 pounds per in2 gage.
If a tank shell has a thickness no greater than _____, the risk of failure due to brittle fracture is minimal, provided that an evaluation for suitability of service per section 2 of API 653 has been performed.
a. 0.875"
b. 0.750"
c. 0.625"
d. 0.500" - CORRECT ANSWER 0.500"
All tanks shall be given a visual external inspection by an inspector qualified in accordance with API 653 at least every _____ years or RCA / 4N years, whichever is less.
a. 2.5
b. 3
c. 5
d. 10 - CORRECT ANSWER 5
Where concrete ringwalls are provided under the shell, the top of the ring shall be level within _____ in any 30 feet of the circumference measured from the average elevation.
a. Plus or minus 1/16"
b. Plus or minus 1/8"
c. Plus or minus 3/16"
d. Plus or minus ¼" - CORRECT ANSWER Plus or minus 1/8"
If a tank is designed to have a leak detection and containment system, the minimum thickness of the bottom plates at the next inspection can be:
a. 0.10"
b. 0.09"
c. 0.07"
d. 0.05" - CORRECT ANSWER 0.05"
The maximum vertical and horizontal dimension of a lapped patch repair plate is _____ inches and _____ inches respectively.
a. 48,72
b. 36,60
c. 30,48
d. 24,48 - CORRECT ANSWER 48,72
When gouging or grinding welds to remove defects, cavities often result. These cavities must be examined visually and by:
a. RT or UT
b. ET or UT
c. MT or PT
d. Magnetic resonance or RT - CORRECT ANSWER MT or PT
Completed welds of stress relieved assemblies of shell penetrations shall be examined by visual and magnetic particle or liquid Penetrant methods:
a. Before stress relief and after stress relief
b. After stress relief and after hydrostatic test
c. Before stress relief and before hydrostatic test
d. After stress relief and before hydrostatic test - CORRECT ANSWER After stress relief and before hydrostatic test
Corrosion that occurs when two metals with different compositions (thus different electrolyte potentials) are connected in an electrolyte (usually oil) is called:
a. Cell corrosion
b. Galvanic corrosion
c. Stray current corrosion
d. Anodic-cathodic corrosion - CORRECT ANSWER Galvanic corrosion
What are two systems of cathodic protection normally used for corrosion control?
a. Polarization and impressed current
b. Stray current and impressed current
c. Galvanic and impressed current
d. Sacrificial anode and polarization - CORRECT ANSWER Galvanic and impressed current
When calculating the critical length "L" and determining the least minimum thickness "t2" of an area of a tank shell, the critical length cannot be more than:
a. 20"
b. 30"
c. 40"
d. 50" - CORRECT ANSWER 40"
The simplest type of atmospheric storage tank is the:
a. Cone roof
b. Floating roof
c. Breather-roof
d. Lifter-roof - CORRECT ANSWER Cone roof
Corrosion on the underside of tank bottoms that rest on pads or on the soil cannot be inspected readily from the outside. If it becomes necessary to make an external inspection of the bottom located near the edge of the tank, the following method can be used when the tank is out of service.
a. Jacking method
b. Magnetic resonance method
c. Tunneling method
d. Electro-magnetic transducer method - CORRECT ANSWER Tunneling method
During an external inspection of an in-service aboveground storage tank, crevices associated with structural steel ladders, stair treads, and platforms plates, etc., where water can collect, should be closely checked by:
a. Picking with a scraper or knife
b. UT shear wave
c. MT or PT
d. RT - CORRECT ANSWER Picking with a scraper or knife
Tank bottoms should be checked thoroughly for thickness over its entire area. UT measurements are usually the first choice. If an UT instrument is not available, what other alternate non-destructive method could be used for quickly checking the condition of the bottom?
a. Thorough visual inspection
b. Hammer testing
c. Tunnel under tank
d. Jack up the tank - CORRECT ANSWER Hammer testing
The internal tank shell should be inspected for corrosion. Two likely corrosion areas are the:
a. Vapor space and liquid level line.
b. Mid-point of liquid-level and the bottom.
c. Plate joints and nozzle connecting joints.
d. Areas near heating coils or agitators. - CORRECT ANSWER Vapor space and liquid level line.
Two of the best tools for visually inspecting inside a tank for cracks is a:
a. "Tank buggy" and a hammer.
b. UT meter and hammer.
c. Pit gage and a rule.
d. Strong light and a magnifying glass. - CORRECT ANSWER Strong light and a magnifying glass
If evidence of cracking is found during the internal inspection of a tank, a thorough investigation should be made using:
a. ET and UT
b. EMAT and VT
c. MT, PT, or RT or UT shear wave testing.
d. Hammer testing, vacuum box testing, or hydrostatic testing. - CORRECT ANSWER MT, PT, or RT or UT shear wave testing
_______ is an electrode of an electrochemical cell where oxidation (corrosion) occurs.
a. A cathode
b. An electrolyte
c. An anode
d. A positron - CORRECT ANSWER An anode
_______ is an electrode of an electrochemical cell at which a reduction reaction occurs.
a. A cathode
b. An electrolyte
c. An anode
d. A positron - CORRECT ANSWER A cathode
Radiographs for an evaluated, repaired, or reconstructed tank shall be retained for:
a. 5 years
b. 2 years
c. Agreed time
d. 1 year - CORRECT ANSWER 1 year
In regard to installation of primary and secondary seals, if the roof rim thickness is less than _____ inch thick, it shall be replaced.
a. 0.08
b. 0.19
c. 0.10
d. 0.12 - CORRECT ANSWER 0.10
If it is necessary to replace a roof rim, the new roof rim shall be a min. thickness of:
a. 1/8"
b. 3/8"
c. 1/16"
d. 3/16" - CORRECT ANSWER 3/16"
The min. thickness of new roof plates shall be:
a. ¼" plus any corrosion allowance.
b. 1/8" plus any corrosion allowance.
c. 5/16" plus any corrosion allowance.
d. 3/16" plus any corrosion allowance. - CORRECT ANSWER 3/16" plus any corrosion allowance.
Rim-mounted primary and toroidal seal systems can be removed, repaired, or replaced. To minimize evaporation losses and reduce potential hazards to workers, no more than:
a. 1/3 of the roof seal system should be out of an in-service tank at one time.
b. 1/4 of the roof seal system should be out of an in-service tank at one time.
c. 1/2 of the roof seal system should be out of an in-service tank at one time.
d. 1/5 of the roof seal system should be out of an in-service tank at one time. - CORRECT ANSWER 1/4 of the roof seal system should be out of an in-service tank at one time.
In the event roof live loads exceed 25 pounds per square foot (loads caused by insulation, vacuum on the tank, snow loads), the plate thickness shall be:
a. 3/16" plus any corrosion allowance.
b. ¼" plus any corrosion allowance.
c. Based on analysis using proper allowable stresses.
d. Determined by using the actual thickness measured for the top shell course. - CORRECT ANSWER Based on analysis using proper allowable stresses
Where tank foundations true to a horizontal plane are specified and concrete ringwalls are not provided, the tolerances are as follows:
a. The foundation under the shell shall be level with plus or minus 1/8" in any 10' of circumference and within plus or minus ½" in the total circumference measured from the average elevation.
b. The foundation under the shell shall be level with plus or minus 1/4" in any 10' of circumference and within plus or minus ¾" in the total circumference measured from the average elevation.
c. The foundation under the shell shall be level with plus or minus 1/16" in any 10' of circumference and within plus or minus ¼" in the total circumference measured from the average elevation.
d. The foundation under the shell shall be level with plus or minus 3/8" in any 10' of circumference and within plus or minus 5/8" in the total circumference measured from the average elevation. - CORRECT ANSWER The foundation under the shell shall be level with plus or minus 1/8" in any 10' of circumference and within plus or minus ½" in the total circumference measured from the average elevation.
When a tank is reconstructed, the weldability of the steel shall be:
a. Confirmed by an inspector.
b. Disregarded.
c. Confirmed by a welder.
d. Verified. - CORRECT ANSWER Verified
When a tank is reconstructed, the welder or welding operator's identification mark shall be hand or machine stamped adjacent to and at intervals along the completed weld not exceeding:
a. 4' along completed welds.
b. 3' along completed welds.
c. 6' along completed welds.
d. 5' along completed welds. - CORRECT ANSWER 3' along completed welds
In lieu of stamping complete welds:
a. A certified copy of the welder's time sheets may be submitted
b. A record that identifies the constructor of the tank may be submitted
c. A record may be kept that identifies the welder or welding operator employed for each welded joint
d. A certified written statement from a jurisdictional body may be submitted - CORRECT ANSWER A record may be kept that identifies the welder or welding operator employed for each welded joint
The ____________ do not require welder identification.
a. Floor sketch plate welds and shell to bottom welds.
b. Horizontal joint welds and nozzle welds.
c. Floor joint welds and nozzle repad welds.
d. Roof plate welds and flange-to-nozzle-neck welds. - CORRECT ANSWER Roof plate welds and flange-to-nozzle-neck welds
What type of tank settlement can often be predicted in advance, with sufficient accuracy from soil tests?
a. Planar tilt
b. Out-of-plane settlement
c. Uniform settlement
d. Rigid body tilting - CORRECT ANSWER Uniform settlement
What type of tank settlement does not induce stresses in the tank structure? It does cause problems with piping and other attachments to the tank from outside.
a. Planar tilt
b. Out-of-plane settlement
c. Uniform settlement
d. Rigid body tilting - CORRECT ANSWER Uniform settlement
What type of tank settlement generally rotates the tank in a tilted plane?
a. Differential settlement
b. Out-of-plane settlement
c. Uniform settlement
d. Rigid body tilting - CORRECT ANSWER Rigid body tilting
What type of tilt of a tank will cause an increase in the liquid level and, therefore, an increase in the hoop stress in the tank shell? It also can cause binding of seals on floating roofs.
a. Uniform settlement
b. Rigid body tilting
c. Out of plane settlement
d. Differential settlement - CORRECT ANSWER Rigid body tilting
What type of tank settlement is characterized by settlement of a tank at different rates at different locations? This results in non-planar configurations which induces additional stresses in a tank shell.
a. Out-of-plane settlement
b. Uniform settlement
c. Planar tilt
d. Rigid body tilting - CORRECT ANSWER Out-of-plane settlement
What type of tank settlement leads to a lack of circularity at the top of the tank, and may induce improper functioning of the floating roof? Also, flat spots may develop on the tank shell.
a. Differential settlement
b. Uniform settlement
c. Planar tilt
d. Rigid body tilting - CORRECT ANSWER Differential settlement
What allowable stress is used for API 653 eval. of riveted tank shell thickness?
a. 20000 psi
b. 21000 psi
c. 26000 psi
d. 32000 psi - CORRECT ANSWER 21000 psi
The selection of a lapped patch repair plate thickness to reinforce areas of deteriorated shell plates or to repair small shell leaks shall be based upon design that conforms to the applicable standard of construction and API 653, using a joint efficiency not exceeding:
a. 0.35
b. 0.60
c. 0.70
d. 0.85 - CORRECT ANSWER 0.35
The minimum dimension of a lapped patch repair plate is:
a. 8"
b. 6"
c. 12"
d. 10" - CORRECT ANSWER 6"
When calculating the maximum allowable hydrostatic test stress for a new tank shell, the:
a. Gross plate thk,. Less any corrosion allowance, shall be used in the calculation.
b. Min. measured plate thk., Less any corrosion allowance, shall be used in the calculation.
c. Gross plate thk., Including any corrosion allowance, shall be used in the calculation.
d. Average plate thk., Less any corrosion allowance, shall be used in the calculation. - CORRECT ANSWER Gross plate thk., Including any corrosion allowance, shall be used in the calculation.
When the service of an aboveground storage tank is changed:
a. The effects on normal venting should be considered, but emergency venting requirements will not change.
b. The effects on normal venting must be considered, but emergency venting requirements will not change.
c. The effects of normal and emergency venting should be considered.
d. The effects of normal and emergency venting shall be considered. - CORRECT ANSWER The effects of normal and emergency venting shall be considered.
The thickness to be used for each shell course when checking the design for a reconstructed and relocated tank shall be based on measurements taken within _____ days prior to relocation.
a. 90
b. 100
c. 180
d. 200 - CORRECT ANSWER 180
Which of the listed is not considered a major repair or major alteration of a storage tank?
a. Installation of a new bottom.
b. Installation of a NPS 1 connection on the shell.
c. Partial or complete jacking of a tank shell.
d. Installation of a NPS 16 connection beneath the design liquid level. - CORRECT ANSWER Installation of a NPS 1 connection on the shell
Measurements to verify the dimensional tolerances of a reconstructed aboveground storage tank shall be taken:
a. During the hydrostatic test of a tank.
b. After the hydrostatic test of the tank.
c. In lieu of the hydrostatic test of the tank.
d. Before the hydrostatic test of the tank. - CORRECT ANSWER Before the hydrostatic test of the tank
The most common stray current and the potentially most damaging to aboveground storage tank bottoms is:
a. Alternating current.
b. Direct current.
c. Turbulent current.
d. Ionization current. - CORRECT ANSWER Direct current
An example of galvanic reaction that could lead to corrosion is:
a. When CS material is connected to a CS tank.
b. When cast iron material and lead material are connected together.
c. When high silicon cast iron and copper are connected together.
d. When a SS or copper material is connected to a CS tank. - CORRECT ANSWER When a SS or copper material is connected to a CS tank
Current, in galvanic corrosion, is considered to flow:
a. From the metal closest to the source of a stray current that affects corrosion.
b. From the more active metal (anode) to the less active metal (cathode).
c. From the less active metal (anode) to the more active metal (cathode).
d. From the interior of the tank bottom where there are water bottoms to the more active underside of the tank bottom. - CORRECT ANSWER From the more active metal (anode) to the less active metal (cathode)
Electric current takes the path of _____ resistance.
a. Most
b. Severe
c. Least
d. Optimum - CORRECT ANSWER Least
A cushion of new _______ may provide many of the same advantages as a concrete cushion for reducing corrosion and eliminating the need for cathodic protection.
a. Asphalt
b. Sand
c. Oil
d. Gravel - CORRECT ANSWER Asphalt
The projection of the bottom plate beyond the outside toe of the shell-to-bottom weld shall be at least _____ inch.
a. 0.5625
b. 0.5000
c. 0.4375
d. 0.3750 - CORRECT ANSWER 0.3750
Corrosive soil beneath a high resistivity foundation material (for example concrete or asphalt that has cracked) may contaminate the foundation fill by:
a. Climatic changes.
b. Capillary action.
c. Oxygen aeration.
d. Hydrogen infiltration. - CORRECT ANSWER Capillary action
In certain cases when considering protecting a tank bottom, internal cathodic protection in conjunction with a _____ may be applicable.
a. Control
b. Lining
c. Rheostat
d. Mixer - CORRECT ANSWER Lining
If large particle sizes are used in the cushion beneath a tank bottom, differential aeration ______ may result at points where the large particles or debris contact the bottom.
a. Contaminant
b. Attenuation
c. Corrosion
d. Resonance - CORRECT ANSWER Corrosion
The major reason for inspecting an aboveground storage tank for deterioration due to corrosion is to:
a. Satisfy API requirements.
b. Determine the physical condition of the tank; find & measure the extent of corrosion.
c. Satisfy jurisdictional (governmental) requirements.
d. Satisfy owner / user requirements. - CORRECT ANSWER Determine the physical condition of the tank; find & measure the extent of corrosion.
Tank-to-soil potential measurements are typically taken with:
a. The current applied.
b. A wheat stone bridge.
c. The power supply off.
d. A ground fault interrupter. - CORRECT ANSWER The current applied
A lapped patch is rectangular in shape (8" x 12"). The lapped patch is to be located midpoint of a third shell course plate. What minimum radius (if required) should the corners be?
a. No radius required.
b. 1" radius.
c. 2" radius.
d. 1.5" radius. - CORRECT ANSWER 2" radius
What is generally considered the normal service life of a properly selected and applied internal tank bottom lining?
a. 5-10 years.
b. 10-20 years.
c. 15-25 years.
d. 20-30 years. - CORRECT ANSWER 10-20 years
A thin film tank bottom lining is considered to be ____ mils or less.
a. 5
b. 10
c. 15
d. 20 - CORRECT ANSWER 20
A thick film tank bottom lining is considered to be greater than ____ mils.
a. 10
b. 15
c. 20
d. 25 - CORRECT ANSWER 20
Define forced-curing of an internal tank lining.
a. It is the acceleration of curing by decreasing the temperature below ambient, accompanied by forced air circulation.
b. It is the acceleration of curing by increasing the temperature above ambient, accompanied by forced air circulation.
c. It is the acceleration of curing by increasing the temperature above ambient, and restricting the movement of air in the curing area. - CORRECT ANSWER It is the acceleration of curing by increasing the temperature above ambient, accompanied by forced air circulation.
Define holiday in relation to a tank internal lining.
a. A holiday is a discontinuity in a coating film that exposes the metal surface to the environment.
b. A holiday is an agent in a coating film that allows curing of the liner by polymerization.
c. A holiday is a curing agent that has been combined with epoxy.
d. A holiday is a black hydrocarbon residue remaining in a liner after addition of aromatic solvents. - CORRECT ANSWER A holiday is a discontinuity in a coating film that exposes the metal surface to the environment.
Generally, thin-film linings may be applied to:
a. Old tanks and to bottoms of storage tanks that have experienced heavy corrosion.
b. Old tanks and to bottoms of tanks that have maximum corrosion.
c. New tanks and to bottoms of storage tanks that have experienced minimal corrosion.
d. New tanks storing very corrosive material & to tank bottoms that have heavy corrosion. - CORRECT ANSWER New tanks and to bottoms of storage tanks that have experienced minimal corrosion.
If caustic is stored in an aboveground storage tank, what would be the most likely problem found and where?
a. Pitting on the tank bottom and shell near internal heating coils.
b. General smooth corrosion on the tank bottom near internal heating coils.
c. Severe corrosion and general thinning in the lower part of the tank.
d. Caustic embrittlement resulting in cracks in welds and HAZ's around connections for internal heating units or coils. - CORRECT ANSWER Caustic embrittlement resulting in cracks in welds and HAZ's around connections for internal heating units or coils.
When checking for pits, bulges, and depressions during an internal inspection of the shell and bottom of a tank using a flashlight, the flashlight beam gives best results when held:
a. Perpendicular to the surface being inspected.
b. Parallel and close to the surface to be inspected. - CORRECT ANSWER Parallel and close to the surface to be inspected.
Abrasive blasting prior to installation of an internal tank lining should not be performed if the temperature of the steel surface is less than ____ above the dew point.
a. 32F
b. 5F
c. -5F
d. 15F - CORRECT ANSWER 5F
In actual thickness determination of corroded areas, according to API 653 what two thickness measurements are the same?
a. t 2 and t 1
b. t nom and t 1
c. t 1 and t avg
d. t avg and t 2 - CORRECT ANSWER t 1 and t avg
Prior to determining the need for cathodic protection of an aboveground storage tank:
a. A full evaluation of tank history is advised.
b. A check of the tank welds is advised.
c. A full cost evaluation should be made.
d. A check of regulatory requirements should be made. - CORRECT ANSWER A full evaluation of tank history is advised.
A butt-weld constructed aboveground atmospheric storage tank with a bottom shell course that measured 1" thick when it was originally built was inspected 10 years after it was put in service. A general thickness of 0.87" was measured on the bottom course during the inspection. What is the corrosion rate?
a. 0.13" per year
b. 1.3 mil per year
c. 0.013 mil per year
d. 0.013" per year - CORRECT ANSWER 0.013" per year
Lapped patch repair plates are an acceptable form of repair for butt-welded, lap-welded, and riveted tank shells, but only when:
a. Authorized by underwriter laboratories.
b. Allowed by API 650.
c. Specified by the tank owner.
d. Authorized by the maintenance organization. - CORRECT ANSWER Specified by the tank owner
A successfully operating cathodic protection system can usually be determined by measuring the minimum voltage across the structure-electrolyte interface relative to a saturated copper-copper sulfate reference electrode. This measurement should be a minimum of how many volts?
a. -0.55 volts
b. +0.65 volts
c. +0.75 volts
d. -0.85 volts - CORRECT ANSWER -0.85 volts
A deep anode ground-bed uses impressed current anodes installed in a vertical hole typically:
a. Under 20' deep
b. 50" deep
c. 10 meters deep
d. 50' or more - CORRECT ANSWER 50' or more
What type of weld is usually considered the preferred means for connecting the negative rectifier lead wire to the structure to be protected?
a. A regular electric weld.
b. A silver soldered connection.
c. A brazed weld connection.
d. A powder weld connection-cadweld, thermite, or equivalent. - CORRECT ANSWER A powder weld connection-cadweld, thermite, or equivalent
The minimum height of tank liquid above the hot tap location shall be at least _____ feet during the hot tapping operation.
a. Three
b. Two
c. Zero
d. Four - CORRECT ANSWER Three
Records related to the effectiveness of cathodic protection should be retained for a period of _____ years unless a shorter period is specifically allowed by regulation.
a. 1
b. 3
c. 5
d. 7 - CORRECT ANSWER 5
Cathodic protection surveys are recommended to ensure effectiveness every:
a. 12 months.
b. 18 months.
c. 24 months.
d. 36 months. - CORRECT ANSWER 12 months
A tank has a thickness of 0.83 inch on its bottom course. The minimum thickness of the bottom course is 0.75 inch. What is the remaining life of the tank if its rate is 0.007 inch per year?
a. 5.71 years.
b. 11.43 years.
c. 20.00 years.
d. 1.14 years. - CORRECT ANSWER 11.43 years
A lapped repair plate may cross any butt-welded vertical or horizontal shell seam that has been ground flush. How much overlap beyond the seam is required?
a. 3"
b. 9"
c. 6"
d. 12" - CORRECT ANSWER 6"
External leaks on aboveground storage tank shells are often marked by a:
a. Oxide layer formed on steel during hot forming operations.
b. Discoloration or the absence of paint in the area below the leak.
c. Setting up or hardening between two or more chemicals.
Definite surface profile or roughness. - CORRECT ANSWER Discoloration or the absence of paint in the area below the leak [Show Less]