API 510 Study – Inspection Techniques, Planning & Exam Prep

A comprehensive set of question-and-answer flashcards covering inspection techniques, planning, codes, damage mechanisms, NDE, welding, repairs, and related API/ASME requirements for API 510 exam preparation.

What document outlines internal and external visual inspection procedures for pressure vessels?

API 572, Chapter 5 (External) & Chapter 6 (Internal)

What tools are commonly used during internal visual inspection?

Flashlights, mirrors, borescopes, measuring tapes, ultrasonic thickness gauges

What welding inspection tasks must be performed before, during, and after welding?

Before: Verify WPS and cleanliness; During: Monitor interpass temperatures and technique; After: Visual check and NDE

What limitations apply to visual testing (VT)?

Limited to surface-breaking defects only; cannot detect subsurface flaws

What is the primary objective of external inspection?

To identify deterioration such as corrosion, leaks, or mechanical damage

When must insulation be removed for visual inspection?

When corrosion under insulation (CUI) is likely or suspected

Who is responsible for developing the inspection plan?

The Inspector and/or Engineer

What factors influence the inspection plan?

Damage mechanisms, service conditions, corrosion history, and risk

What are the minimum contents of an inspection plan?

Type of inspection, areas to inspect, techniques, extent, and frequency

When is an internal inspection required?

At required intervals unless risk-based inspection (RBI) justifies otherwise

What is RBI and when can it be used?

Risk-Based Inspection; may extend intervals if API 580 is followed and fully documented

What is the inspector's role in planning?

Develop the plan, identify damage mechanisms, and select inspection methods

What section in API 510 defines the next inspection due date?

API 510 §7.1.1 (based on corrosion rate and remaining life)

What should the inspector verify from previous records?

Thickness readings, corrosion rates, past repairs, and failures

When planning an internal inspection for a vessel with CUI potential, which action is most appropriate?

Remove insulation at likely water-ingress points and inspect for CUI

According to API 510, who determines whether RBI can be used instead of the next scheduled internal inspection?

The Owner/User, supported by proper documentation

Which of the following is NOT a factor to consider in an inspection plan?

Age of inspector

During visual inspection you find blistering on the vessel shell. What should you do?

Investigate for potential hydrogen-induced cracking (HIC)

An inspector finds porosity at the toe of a weld. What NDE method can best confirm its depth?

Radiographic Testing (RT)

What is the minimum required in an inspection plan regarding the extent of inspection?

Define what areas will be inspected and by which methods

What type of corrosion is characterized by small, deep pits often covered by corrosion products?

Pitting corrosion

What type of inspection should be prioritized for a vessel in cyclic service?

Internal inspection focused on fatigue cracking and stress corrosion cracking

Which document specifies when postweld heat treatment is required based on thickness and material?

ASME VIII Division 1, Table UCS-56

A weld displays a sharp groove at the toe. Which discontinuity does this indicate?

Undercut

Which PCC-2 article covers fillet weld patches and reinforcements?

Article 216

What is the maximum interval for external visual inspection of a vessel in continuous service without RBI?

5 years

According to API 577, who is responsible for ensuring a welder is qualified before production welding?

The Manufacturer or Contractor

What condition might suggest the presence of MIC (microbiologically influenced corrosion)?

Sharp pits beneath slime or biofilm, often in stagnant zones

Which NDE method is most appropriate for detecting near-surface subsurface cracks?

Magnetic Particle Testing (MT)

What determines the joint efficiency for pressure-vessel calculations per ASME VIII?

Type of weld joint and extent of radiography

What is the recommended UT technique for thickness measurement?

Contact pulse-echo method

What are the four key elements of API 510's scope?

Inspection, repair, alteration, and rerating of pressure vessels

When evaluating pitting, what tool is typically used to measure depth?

Pit depth gauge or ultrasonic thickness gauge with digital display

What formula is used to calculate remaining life?

(t actual – t minimum) / corrosion rate

What code defines acceptance criteria for weld discontinuities in repair welds?

ASME IX and API 577 Chapter 8

According to API 510, what is the primary purpose of an inspection?

To ensure the continued safe operation of pressure vessels

What is the allowable stress for SA-516 Gr. 70 at 650 °F?

17,500 psi

What is the minimum thickness formula for a cylindrical shell under internal pressure?

t = (PR) / (SE - 0.6P)

When should a hydrotest be performed after repairs?

When welds are made on the pressure boundary, unless waived by an engineer

What is the maximum interval between internal inspections if RBI is used?

10 years, if justified and documented

Which method is best for detecting internal corrosion over large areas?

Ultrasonic Testing (UT)

What document defines the roles of the inspector in repair planning?

API 510 §9.2

What is a common sign of stress corrosion cracking (SCC) in austenitic stainless steels?

Branched surface cracks in chloride environments

What information should be included in a weld procedure specification (WPS)?

Base metals, filler metal, welding technique, position, current, etc.

What damage mechanism is associated with high-velocity fluid streams?

Erosion corrosion

Which discontinuity is caused by gas entrapment during solidification?

Porosity

What repair method involves grinding out and rewelding a crack?

Weld build-up

What does the term “component thickness” refer to in API 510?

Minimum allowable thickness required to maintain pressure containment

What type of inspection is most likely used for verifying weld size and location?

Visual Testing (VT)

What is the significance of the term “joint efficiency” in ASME VIII?

Accounts for the reliability of welds based on radiographic testing

What UT technique is recommended for thickness measurement?

Contact pulse-echo method

What tool is typically used for pit depth measurement?

Pit depth gauge or UT

Which document discusses in-service welding requirements?

API 577 Chapter 11.2

Which NDE method is most effective for surface-breaking defects on non-ferromagnetic materials?

Liquid Penetrant Testing (PT)

What API document details pressure relief device inspection and testing?

API 576

What must be included in a PRD inspection report?

Type, set pressure, findings, calibration date, test results

What is Positive Material Identification (PMI) and where is it required?

Method for verifying alloy content; required where material mix-up risk is high

Which code discusses alternative temporary repairs such as enclosures or clamps?

ASME PCC-2 Article 304

What is the role of the owner/user per API 510?

Ensure vessel integrity, assign responsibilities, and approve inspection intervals

What causes hydrogen embrittlement?

Hydrogen absorption and diffusion in high-strength steels

What NDE method detects subsurface inclusions in welds?

Radiographic Testing (RT)

What is the required retention time for inspection records according to API 510?

Until the next turnaround or as required by jurisdiction

What is the primary reason for postweld heat treatment (PWHT)?

Relieve residual stresses and reduce hardness

What kind of flaw does undercut represent in a weld?

Surface groove at the weld toe acting as a stress riser

Which article in PCC-2 covers fillet weld patches?

Article 216

Which API code provides guidance for rerating of vessels?

API 510 §8.5

What is the purpose of a corrosion allowance?

Extra thickness added to compensate for expected metal loss

What inspection technique detects cracks at or near the surface of ferromagnetic materials?

Magnetic Particle Testing (MT)

What defines an alteration as opposed to a repair?

Any change that affects pressure-containing capability not considered a repair

What does API 571 say about caustic cracking?

Occurs in carbon steels exposed to caustic solutions under stress

Who is responsible for verifying the calibration of UT equipment?

The NDE examiner

What is required before starting an in-service weld repair?

Engineering review, qualified procedure, and safety assessment

When performing UT thickness measurements, how often should the instrument be calibrated?

At the start and end of each shift or when readings are questionable

What is the minimum information required in a PQR?

Essential variables, actual test values, and mechanical-test results

Which damage mechanism is most likely in carbon-steel vessels operating above 800 °F?

Creep

How often must an inspection plan be reviewed and updated?

After each inspection or when service conditions change

What inspection method can detect wall thinning over large areas with limited access?

UT with B-scan or C-scan mapping

What is the acceptance criterion for visual inspection of welds?

Free of cracks, excessive undercut, overlap, and other surface discontinuities

What is meant by “pressure boundary” in API 510?

Portion of the vessel that contains pressure, including shell, heads, and nozzles

What welding process uses a continuous wire fed through a torch and gas shield?

GMAW (Gas Metal Arc Welding)

What action is required if vessel thickness is below the minimum required?

Repair, rerate, or retire the vessel

What NDE method detects internal discontinuities in welds without surface preparation?

Radiographic Testing (RT)

Which API code mandates qualifications for inspection personnel?

API 510 §4.2

What type of stress is associated with stress corrosion cracking (SCC)?

Tensile stress

What is the minimum documentation required for a weld repair?

Description of repair, location, date, procedures used, and NDE results

Which section of ASME IX provides the formats for WPS and PQR?

QW-482 and QW-483

What article in ASME PCC-2 covers mechanical clamp repairs?

Article 304

What is an “essential variable” in ASME IX?

Welding condition that, if changed, requires requalification of the procedure

How often should external visual inspections be conducted per API 510 if RBI is not used?

Every 5 years or at the same interval as internal inspection

What is the required hydrotest pressure per ASME VIII?

1.3 × MAWP × (ST / S)

What type of corrosion is typically uniform and predictable over time?

General thinning

What factor distinguishes an alteration from a rerating?

Alteration changes physical design; rerating changes operating parameters

What are the responsibilities of the Authorized Inspector during repair activities?

Witness, review, and verify NDE and code compliance

What welding process is best for precision and low heat input?

GTAW (TIG)

What is the minimum hold time for a hydrotest?

10 minutes

Which technique is best for measuring internal loss in complex geometries?

Ultrasonic corrosion mapping

What is the definition of MAWP?

Maximum Allowable Working Pressure—the maximum pressure a vessel can safely handle at a specific temperature

What does the term “pressure part” include?

Any component that retains pressure, e.g., shell, head, nozzle, flange

What is the typical acceptance criterion for a root crack in a weld?

Rejection—cracks are unacceptable regardless of size

What must an inspector evaluate before approving a temporary repair?

Code compliance, integrity impact, duration, and engineering approval