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

The SOD must be at least 12 inches regardless of source size

Answer

The SOD is left entirely to the radiographer's discretion

Answer

The SOD must be at least 10 times the source diameter

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

Single-wall single-image (SWSI)

Answer

Double-wall single-image (DWSI)

Answer

Panoramic technique

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

Exactly 45 degrees

Answer

90 degrees

Answer

0 degrees (superimposed)

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

One IQI per weld regardless of film length

Answer

IQIs are placed every 6 inches along the weld

Answer

Two IQIs at each end of every film

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

To identify the technician performing the examination

Answer

To mark the weld start location

Answer

To measure source-to-film distance

Question 6

Which radiographic exposure arrangement provides the most uniform density across the full circumference of a large-diameter vessel shell weld in a single shot?

Accepted Answer

Panoramic internal source technique with film wrapped around the outside

Answer

Multiple external source exposures with overlapping films

Answer

DWSI technique from one side

Answer

Gamma source at 90 degrees from film