What requirement does the standard impose for butt welds in tank shells?

• A. Partial penetration
• B. Complete fusion with no gaps
• C. Complete penetration and complete fusion
• D. Loosely fitted

Answer: (C)

The standard requires that butt welds in tank shells achieve complete penetration and complete fusion. This ensures that the welded joint is as strong as the base metal itself, minimizing the potential for leaks or structural weaknesses in the tank. Complete penetration ensures that the weld extends through the full thickness of the materials being joined, while complete fusion guarantees that the weld metal fully integrates with the base metals without any gaps or voids. This requirement is crucial for maintaining the integrity and safety of the tank, particularly when storing volatile or hazardous materials.

In the context of tank design and construction, adhering to this high standard of welding ensures long-term reliability and compliance with safety regulations, which is essential for the operation of storage tanks for oil and other liquids.