According to API 650, what is the minimum size of fillet welds for plates more than 5 mm thick?

• A. 1/4 inch
• B. 3/16 inch
• C. 1/8 inch
• D. 1/2 inch

Answer: (B)

According to API 650 guidelines, the minimum size of fillet welds for plates that are more than 5 mm thick is specified to ensure structural integrity and proper weld performance. A minimum weld size of 3/16 inch is necessary to provide adequate strength and durability, particularly in tanks designed for oil storage, where safety and reliability are critical.

This specified weld size ensures that the joint is capable of withstanding the stresses it will encounter, including factors such as the weight of the contents, environmental loads, and operational pressures. Adhering to this minimum size is essential for compliance with industry standards and helps prevent potential failures that may arise from improper welds, contributing significantly to the overall safety of the tank structure.

Understanding these welding requirements is crucial for engineers and fabricators working with API 650-compliant storage tanks, as proper weld specifications directly relate to the longevity and safety of the installations.