According to B31.3, what percentage of radiographic testing is conducted on circumferential welds in normal service?

According to B31.3, what percentage of radiographic testing is conducted on circumferential welds in normal service?

• A. 20%
• B. 5%
• C. 10%
• D. 15%

Answer: (C)

Understanding how B31.3 handles in-service inspection helps explain why ten percent is used. For circumferential welds in normal service, the code sets a practical minimum sampling rate for radiographic testing to balance reliability with inspection effort. Radiography is a strong method for catching volumetric weld flaws, so inspecting a representative portion of welds provides confidence that fabrication quality is high without radiographing every weld. Ten percent serves as the baseline coverage; if the system is particularly critical or has a history of issues, more extensive testing may be specified, but the standard minimum is ten percent. The other percentages aren’t the baseline requirement for normal service, which is why ten percent is chosen.

Understanding how B31.3 handles in-service inspection helps explain why ten percent is used. For circumferential welds in normal service, the code sets a practical minimum sampling rate for radiographic testing to balance reliability with inspection effort. Radiography is a strong method for catching volumetric weld flaws, so inspecting a representative portion of welds provides confidence that fabrication quality is high without radiographing every weld. Ten percent serves as the baseline coverage; if the system is particularly critical or has a history of issues, more extensive testing may be specified, but the standard minimum is ten percent. The other percentages aren’t the baseline requirement for normal service, which is why ten percent is chosen.