Non-Destructive Examination Methods Flashcards

Which NDE method is used in API 510 fitness-for-service evaluations to characterize the dimensions of an embedded crack-like flaw in a pressure vessel wall for fracture mechanics calculations?

Answer: Phased array ultrasonic testing (PAUT) for both length and through-wall height measurement

Phased array UT (PAUT) combined with TOFD or conventional UT techniques is used to accurately characterize flaw height and length needed for fracture mechanics-based fitness-for-service assessment per API 579.

What condition must be met before applying liquid penetrant testing to a pressure vessel that was in high-temperature service (above 500°F)?

Answer: The surface must be at or below 125°F before applying penetrant

ASME Section V limits penetrant application to surfaces between 40°F and 125°F (unless procedure qualification covers other ranges), so hot surfaces must cool adequately before PT can be applied.

During time-of-flight diffraction (TOFD) ultrasonic examination, what is the 'lateral wave' and why is it significant?

Answer: A wave traveling along the outer surface used as a timing reference for shallow defect sizing

In TOFD, the lateral wave travels along the outer (entry) surface and arrives first at the receiver; it serves as a timing reference and defines the near-surface dead zone above which shallow defects cannot be resolved.

Per API 510 and ASME V, when is a written NDE procedure required to be qualified and demonstrated?

Answer: For all NDE methods whenever ASME Code or API 510 requires written procedures

ASME Section V and API 510 require written, qualified procedures for all specified NDE methods to ensure repeatability, consistency, and documented technical basis for the examination.

What is 'pulsed eddy current' (PEC) testing particularly advantageous for in pressure vessel inspection applications?

Answer: Measuring wall thickness through insulation, fireproofing, and coatings without removal

Pulsed eddy current is specifically designed for screening wall thickness through insulation, fireproofing, and protective coatings, making it the primary tool for CUI detection surveys without insulation removal.

Which of the following is a limitation of radiographic testing that makes it less suitable than UT for detecting planar flaws such as lack-of-fusion in heavy wall pressure vessel welds?

Answer: RT is most sensitive to volumetric flaws and may miss planar flaws not aligned with the radiation beam

Radiographic testing has poor sensitivity to planar discontinuities (cracks, lack-of-fusion) unless the flaw plane is closely aligned with the radiation beam, making UT preferred for detecting these crack-like flaws in heavy welds.

During a magnetic particle test using the yoke technique, how is the adequacy of the magnetic field verified at the examination surface?

Answer: By using a calibrated Hall-effect gauss meter or a pie-shaped (Berthold) field indicator at the surface

The adequacy of the magnetic field at the examination surface is verified using a calibrated Hall-effect gauss meter or a pie-shaped field indicator (also called a Berthold gauge) to confirm sufficient tangential field strength.