Which value corresponds to full radiography joint efficiency?

• A. 0.85
• B. 0.95
• C. 0.90
• D. 1.00

Answer: (C)

Joint efficiency is an efficiency factor used in design calculations to reflect how confident we are in the weld’s quality based on the nondestructive examination performed. When every weld is examined by radiography, the code assigns a specific efficiency value to represent that high level of assurance, but not perfect certainty. The value used for full radiography is 0.90, which recognizes that radiography greatly increases confidence in detecting flaws yet still allows for some residual uncertainty due to factors like defect orientation, film interpretation, and radiographic sensitivity. This 0.90 factor reduces the weld’s effective strength in the design calculations accordingly. The other numbers would correspond to different levels or methods of inspection, or to the idealized case of perfect assurance, which isn’t how the code treats real radiographic testing.