What criteria determine the design of tank bottoms in API 650?

• A. Only the tank's color.
• B. Soil conditions and load distributions.
• C. Manufacturer's preference.
• D. Standard uniform thickness.

Answer: (B)

The design of tank bottoms in API 650 is primarily determined by soil conditions and load distributions. These factors are critical because they ensure that the tank is stable and can carry the weight of the contained liquids, as well as any external loads such as wind or seismic activity. The soil’s bearing capacity will influence how the tank bottom distributes the weight and stress, ensuring it remains structurally sound under operational conditions.

Understanding soil conditions is essential for designing a foundation that can support the tank, as different soil types have varying load-bearing capacities. Load distribution is also key, as it relates to how weight is transferred from the tank and its contents to the ground. By focusing on these aspects, engineers can design tank bottoms that meet performance standards and safety requirements outlined in API 650.

Other choices do not accurately reflect the criteria that should be considered in tank bottom design. For instance, tank color is irrelevant to structural integrity, and manufacturer preferences, while relevant to aesthetics or specific construction details, do not take precedence over engineering principles. Lastly, having a standard uniform thickness is not always feasible; tank bottoms may need varying designs based on the specific requirements of the tank and its environment.