What is the requirement for full radiography for vertical joints when the plate thickness is greater than 1 inch?

• A. All vertical joints must be fully radiographed
• B. Only junctions of vertical and horizontal welds need radiography
• C. Full radiography is not required for any vertical joints
• D. Radiography is only needed for the first 5 feet

Answer: (A)

The requirement for full radiography of vertical joints when the plate thickness exceeds 1 inch is indeed that all vertical joints must be fully radiographed. This standard is in place to ensure the integrity and safety of the welds under conditions that could lead to significant stress or potential failure.

Radiography is a non-destructive testing method that provides a detailed view of the interior of the welds, helping identify defects such as cracks, inclusions, or other irregularities that could compromise the tank's ability to safely store oil. When plate thickness is greater than 1 inch, the risk of potential flaws increases, thus requiring the meticulous inspection provided by full radiography for all vertical joints.

This requirement emphasizes the importance of maintaining high safety standards in welded tank construction, particularly for applications involving the storage of combustible or hazardous materials.