API-653

API 653 primarily applies to which equipment?

• AIn-service aboveground welded storage tanks built for atmospheric or low-pressure service
• BUnderground fuel tanks regulated only as environmental release systems
• CPressurized spheres and bullets designed under pressure-vessel rules
• DPortable tote tanks used only for transportation

What is the main purpose of an external inspection on an API 653 tank?

• ATo directly measure the entire floor underside for corrosion without any other methods
• BTo qualify welders and procedure specifications for future repairs
• CTo rerate the tank automatically to a higher fill height
• DTo assess visible condition of the shell, roof, foundation, appurtenances, and evidence o…

Which inspection activity gives the inspector the best direct view of the tank bottom and shell-to-bottom weld from inside the vessel?

• AA review of old nameplate data only
• BA dike-drainage inspection from outside the shell
• CAn internal inspection after the tank has been taken out of service, cleaned, and made sa…
• DA routine visual walk-around while the tank is full

Who is primarily responsible for maintaining the tank's records and implementing the owner-user inspection program?

• AThe dike-construction contractor
• BThe owner-user organization
• CThe welder who performed the last repair
• DAny NDE technician who last visited the site

What is the authorized inspector's core role under API 653?

• ATo determine whether the tank and related work are acceptable under the standard
• BTo serve as the tank's day-to-day operator
• CTo replace the owner-user's recordkeeping system
• DTo approve electrical one-line diagrams for the whole facility

Before a person enters a tank for internal inspection, what must happen first?

• AThe tank should stay connected to active product lines for ventilation
• BA hydrotest should be run while personnel are inside to check leaks
• COnly the floating roof drains need to be opened
• DThe tank must be isolated, cleaned as needed, tested for safe entry conditions, and enter…

Why is reviewing prior thickness data useful before a new inspection?

• AIt guarantees the tank can be rerated upward
• BIt replaces the need to review the current service conditions
• CIt helps the inspector trend corrosion rates and judge how deterioration is progressing o…
• DIt eliminates the need for any new field measurements

What tank area commonly deserves close attention during internal inspection because water and sludge often accumulate there?

• AThe handrail paint on the stair landing only
• BThe tank bottom, especially low spots and the shell-to-bottom region
• CThe exterior stair treads only
• DThe dike wall cap only

Which condition most strongly suggests corrosion under insulation on a tank shell?

• ADamaged insulation jacketing with moisture entry points and staining at seams or penetrat…
• BA clean, dry shell with newly installed intact insulation
• CAn accurate level gauge reading
• DA recently calibrated overfill alarm

Why are pressure and vacuum vents included in external inspection scope?

• ABecause they are used to measure shell thickness directly
• BBecause they replace the need for overfill protection systems
• CBecause they are only decorative appurtenances with no integrity function
• DBecause blocked or malfunctioning vent devices can expose the tank roof and shell to dama…

If a tank's service changes to a more corrosive product, what should happen before simply continuing operation at the previous interval?

• AOnly the roof color needs to be updated
• BThe shell thickness history should be discarded and ignored
• CThe owner-user and inspector should review whether the tank is suitable for the new servi…
• DNothing, because service changes never affect API 653 decisions

What is a good reason to review prior settlement surveys during a current inspection?

• AThey automatically authorize a reconstruction
• BThey help show whether shell or foundation movement is stable, slowing, or continuing to…
• CThey replace the need to visually inspect the foundation
• DThey prove corrosion no longer matters

Why is the shell-to-bottom junction treated as a critical inspection area?

• AIt experiences important structural loading and is often exposed to corrosion or distorti…
• BIt is never in contact with product or moisture
• CIt has no effect on settlement interpretation
• DIt can be ignored if the stairway looks acceptable

Which record would be most useful when evaluating whether a previous repair was properly controlled?

• AOnly a photo of the tank from across the dike
• BOnly the operator's shift schedule
• COnly the original purchase order for the tank from decades ago
• DDocumentation showing the repair plan, materials, welding details, examination results, a…

A wet area, staining, or dead vegetation near the tank perimeter outside the shell can indicate what concern?

• ASuccessful cathodic protection performance only
• BA welder qualification issue only
• CPossible bottom leakage or release from the tank system
• DGuaranteed overpressure in the vapor space only

What is the best reason to inspect roof drains on a floating-roof tank?

• AThey eliminate the need to inspect the roof seals
• BPlugged or damaged drains can allow water accumulation that affects roof loading and oper…
• CThey determine the tank's material toughness rating
• DThey are used instead of overfill alarms

During an external inspection, which observation most directly points to potential foundation-related distress?

• AOut-of-plane shell distortion or bottom-edge irregularity near the shell base
• BA recently repainted handrail
• CA current calibration sticker on the level gauge
• DA spare vent cap stored in the maintenance shop

Why should nozzles and manways be included in routine tank inspection?

• AThey are outside the scope of API 653 once the tank is in service
• BThey matter only if the roof is floating
• CThey affect only the color of the nameplate
• DThey can show leakage, local corrosion, distortion, and attachment-related cracking or ov…

What is the best reason to clean a tank floor adequately before internal inspection?

• ACleaning is done only to improve paint appearance for visitors
• BA floor cannot be inspected unless it is immediately relined first
• CInspectors need a surface condition that allows meaningful visual examination and thickne…
• DA dirty floor automatically proves the tank has failed API 653

If the tank nameplate or repair history does not match the current configuration, what should the inspector do?

• AReplace the vent valves first and close the inspection
• BTreat it as a documentation discrepancy that needs evaluation and correction before relyi…
• CIgnore it because field conditions always override records
• DAssume the tank has a higher allowable fill height

Which statement best describes the first shell course?

• AIt is the lowest shell course and is especially important because it sees the highest hyd…
• BIt is the topmost shell course above the roof line
• CIt is the course with the lowest stress because product weight is carried elsewhere
• DIt refers only to a temporary erection ring used during construction

Why is a dike-area walkdown useful during tank inspection?

• AIt replaces the need to inspect the tank roof
• BIt is only required when new shell plates are being rolled in the shop
• CIt determines whether welders remain qualified under ASME IX
• DIt can reveal drainage issues, release evidence, shell-base wetness, and conditions that…

What is the main reason to mark and preserve settlement reference points?

• AThey eliminate the need for any shell-thickness measurements
• BThey are used only to identify welders during repairs
• CThey provide repeatable locations so future surveys can be compared on the same basis
• DThey are decorative witness marks with no technical value

When reviewing an insulated tank externally, why are nozzles, clips, and penetrations often checked closely?

• AThey change the tank from atmospheric service to pressure-vessel service
• BThose details commonly create water-entry points and local CUI risk
• CThey are exempt from visual inspection requirements
• DThey permanently prevent shell corrosion by design

Which condition is most likely to interfere with reliable visual assessment of an internal bottom surface?

• AHeavy sludge or residue left on the floor
• BA clearly visible reference mark
• CA clean and dry inspection lane
• DA documented prior floor scan

Why is it risky to rely only on one old thickness reading when setting the next inspection interval?

• AA single reading is always more conservative than multiple readings
• BAPI 653 prohibits recording thickness data at all
• CIntervals are set only by roof color and vent type
• DOne reading does not establish a reliable corrosion trend or show whether damage is local…

What is the best reason to inspect attached stairways, platforms, and handrails during a tank inspection?

• AThey replace the need to check the shell base
• BThey are only inspected when a hydrotest is scheduled
• CThey are appurtenances that can affect safe access and may also show corrosion or attachm…
• DThey determine the tank's shell joint efficiency

A shell area shows bulging near a nozzle reinforcement pad. What is the best interpretation?

• AIt automatically qualifies as acceptable because the shell is thicker nearby
• BIt should be treated as a potential local-distortion or overstress issue that needs evalu…
• CIt proves the roof vents are oversized
• DIt means floor corrosion can be ignored

Why does API 653 inspection planning usually review current service, product history, and water accumulation issues together?

• ABecause deterioration patterns depend strongly on what the tank stores and how water or c…
• BBecause service history affects only the paint color selection
• CBecause API 653 ignores corrosion mechanisms once the tank is in operation
• DBecause product history matters only during new-tank fabrication

What is the most direct reason to retain repair records for future inspectors?

• ARecords are kept only to decorate the quality office
• BRepair records matter only until the tank returns to service for one day
• CFuture inspections are required to ignore all historical repair information
• DFuture integrity decisions often depend on knowing what was changed, where it was changed…

If the bottom edge of the shell appears uneven relative to the foundation, what topic should the inspector immediately think about?

• ARadiographic film density only
• BVacuum-box soap solution only
• CSettlement or foundation movement
• DWelder continuity logs only

Which statement about internal inspection intervals is most accurate?

• AThey are unrelated to remaining life or bottom corrosion risk
• BThey should be based on condition, corrosion behavior, and API 653 rules rather than on a…
• CThey are always the same for every tank regardless of service or condition
• DThey are set only by the welder who made the last repair

Why can a roof-to-shell area deserve special attention during inspection?

• AIt may collect moisture, suffer corrosion, and show cracking or distortion at a structura…
• BIt sees no environmental exposure once the tank is painted
• CIt is inspected only if the shell has no courses
• DIt never affects venting or weather-tightness

What is the best reason to check a floating-roof seal during an inspection?

• AThe seal determines shell impact-test exemption automatically
• BThe seal is unrelated to roof performance
• CThe seal replaces the need to inspect pontoon condition
• DSeal condition affects vapor control, product loss, and roof operation around the shell i…

A tank has incomplete original drawings but solid inspection records from the last 15 years. What should the inspector do?

• AIgnore the field condition because old drawings are missing
• BAutomatically rerate the tank to the highest historical fill level
• CUse the available records, field findings, and engineering judgment rather than stop the…
• DAssume the tank can no longer be inspected under API 653

Why might a bottom leak not be obvious from inside the tank alone?

• ABecause floor corrosion always appears first at the roof
• BSome underside corrosion or leakage paths develop below the visible floor surface and may…
• CBecause bottom leaks can never occur on welded tanks
• DBecause internal inspections are prohibited from examining the floor