What is the required minimum corroded thickness for all bottom plates according to API 650?

• A. 0.5"
• B. 0.236"
• C. 0.125"
• D. 0.75"

Answer: (B)

The required minimum corroded thickness for all bottom plates according to API 650 is specified as 0.236 inches. This standard is set to ensure the structural integrity and safety of storage tanks used for oil storage.

This minimum thickness consideration is crucial because it accommodates potential corrosion over the lifecycle of the tank. Corrosion can significantly weaken the bottom plates, which are often in direct contact with the soil or concrete foundation and are susceptible to moisture and other corrosive agents. By establishing a baseline of 0.236 inches, API 650 allows for a safeguard against failures that can arise from excessive corrosion, thereby helping to maintain the overall reliability and functional safety of the tank structure.

The other thickness options do not meet the standard parameters outlined in the API 650, which emphasizes the importance of proper material thickness in the design and maintenance of storage tanks. Therefore, the choice of 0.236 inches aligns with the operational requirements and safety guidelines set forth in the standard.