What is a Thickened Insert Plate?

• A. A plate added to improve the thermal efficiency of a tank
• B. A steel plate that replaces part of a shell plate with a nominal thickness greater than 0.125"
• C. A reinforcement plate added during external inspections
• D. A special coating used to prevent corrosion

Answer: (B)

The correct choice describes a thickened insert plate as a steel plate that replaces part of a shell plate with a nominal thickness greater than 0.125". In the context of API 650, these plates are typically used to reinforce areas of a tank where additional strength is needed. This could be in response to wear, stress concentration, or specific design requirements. The insertion of a thicker plate helps maintain the structural integrity of the tank and can be essential for ensuring safety and compliance with industry standards.

The significance of the thickness specification, which is greater than 0.125", indicates that the insert plate provides substantial reinforcement compared to the standard shell plates, which might have a lesser thickness. This is important in applications where loads or corrosion could compromise the integrity of a thinner plate.

Other choices do not accurately define the thickened insert plate within the context of tank design and construction as per API 650. They address unrelated concepts, such as thermal efficiency, reinforcement during inspections, or coatings for corrosion prevention, which do not embody the specific function and definition of thickened insert plates in tank construction and maintenance.