According to API 650 Annex I, what is the maximum shell thickness for tanks supported by grillage?

• A. 1/2"
• B. 3/4"
• C. 1/4"
• D. 5/8"

Answer: (A)

The maximum shell thickness for tanks supported by grillage, as outlined in API 650 Annex I, is established to ensure structural integrity while also considering weight and stress factors. A thickness of 1/2 inch strikes a balance between providing adequate strength to support the operational pressure and load conditions without becoming excessively heavy or cumbersome, which could introduce other structural challenges. This standardization helps in maintaining uniformity in design practices for tanks and ensures compliance with safety regulations during their operation and maintenance.

This limit accommodates the various operational scenarios tanks may face while also simplifying the design requirements for engineers and reducing potential fabrication complications. The careful consideration of maximum shell thickness is a critical aspect of tank design, contributing to durability and safety.