What defines a sketch plate in the context of API 650?

• A. A plate for attaching the tank lid
• B. A plate on which the shell of the tank will rest
• C. A reinforcement plate inside the tank
• D. A decorative plate for the tank

Answer: (B)

The correct answer identifies a sketch plate as a plate on which the shell of the tank will rest. In the context of API 650, the sketch plate serves a crucial structural function, as it is positioned at the bottom of a tank. Its primary role is to provide a stable base for the tank shell, ensuring proper alignment and support when the tank is constructed. This plate helps distribute the weight and stress of the shell evenly across its area, contributing to the overall stability and integrity of the tank structure.

Understanding the importance of a sketch plate in tank design highlights its role in maintaining the design principles outlined by API 650, which seeks to ensure safety and functionality in storage tanks. The design and placement of this plate are essential to prevent potential issues such as buckling or uneven settling during the tank's operation.