CRI CRI Pipe & Pressure Vessel Inspection

Question 1

For radiographic examination of pipe welds per ASME B31.3, what is the minimum source-to-object distance (SOD) requirement relative to the source size?

Accepted Answer

The SOD must produce geometric unsharpness (Ug) no greater than 1/100 of the weld thickness or 0.020 inch, whichever is smaller

Answer

ASME B31.3 requires that geometric unsharpness not exceed the lesser of 1/100 of the weld thickness or 0.020 inch, which governs minimum SOD selection.

Question 2

Which radiographic technique is preferred for inspecting small-diameter pipe welds (under 3.5 inch OD) to achieve full-volume coverage in a single exposure?

Accepted Answer

Double-wall double-image (DWDI)

Answer

DWDI technique is used for small-diameter pipe because the source is placed outside and the image of the near and far wall weld are both recorded on the same film.

Question 3

When using the elliptical (double-wall double-image) technique on pipe, what is the recommended offset angle to separate the two weld images?

Accepted Answer

Approximately 15–25 degrees from the plane of the weld

Answer

An offset angle of 15–25 degrees separates the two weld oval images on the film to allow independent interpretation of each wall.

Question 4

For a circumferential weld in a pressure vessel shell, how many IQI (penetrameter) placements are required for a full radiographic examination per ASME Section V?

Accepted Answer

One IQI per film for film lengths up to 14 inches, two IQIs for longer films

Answer

ASME Section V Article 2 requires one IQI per film for single-film exposures up to 14 inches, and two IQIs (one at each end) for longer films.

Question 5

In pipeline girth weld radiography, what is the purpose of the 'back-scatter' lead marker ('B') placed behind the film?

Accepted Answer

To detect radiation scattered from behind the film that could degrade image quality

Answer

If the 'B' marker appears as a light image on the radiograph, back-scatter is excessive and the exposure must be repeated with added back-scatter shielding.

(CRI) Certified Radiographic Interpreter Practice Test

(CRI) Certified Radiographic Interpreter Practice Test

CRI CRI Pipe & Pressure Vessel Inspection