What is the attachment weld requirement for bottom and annular plates with a nominal thickness less than 1/2"?

• A. Continuous fillet weld laid on each side of the shell
• B. Single fillet weld on the outer edge of the shell
• C. Continuous groove weld around the perimeter
• D. Spot welds at each joint connection

Answer: (A)

The correct answer stipulates that a continuous fillet weld is required on each side of the shell for attachment of bottom and annular plates with a nominal thickness less than 1/2 inch. This requirement ensures that there is a robust and continuous connection between the bottom and annular plates and the tank shell, thereby enhancing the structural integrity of the tank and ensuring it can adequately support the loads it experiences during operation.

Continuous fillet welds provide a strong connection that distributes stresses effectively across the welded area, which is particularly important for thinner materials that may be more susceptible to stress concentrations and potential failure points. By placing the weld on each side, this requirement also aids in achieving a more balanced joint that resists distortions and provides a more reliable seal against leaks.

Other options, such as single fillet welds or spot welds, would not provide the same level of strength and continuity needed for effective attachment and long-term durability of the welded tank structure. Continuous groove welds, while strong, are typically used for thicker materials or in different configurations, making them unsuitable for this specific thickness requirement. Thus, the emphasis on continuous fillet welds aligns with best practices for maintaining the integrity and safety of welded storage tanks.