For a vessel subject to uniform corrosion, what is the minimum number of thickness measurements required?

The minimum number of thickness measurements required for a vessel subject to uniform corrosion is one on each major design section. This practice is rooted in the need to effectively assess the structural integrity and safety of pressure vessels that experience corrosion over time.

By taking one thickness measurement in each major design section, inspectors can determine the extent of corrosion and the remaining wall thickness. This method ensures that all significant areas are evaluated, allowing for a comprehensive understanding of the vessel's condition. Uniform corrosion can affect different sections of the vessel to varying degrees based on factors like fluid flow, temperature, and material properties. Therefore, measuring each major design section allows inspectors to identify areas that may be more susceptible to corrosion and require further monitoring or remedial action.

This approach is aligned with best practices in vessel inspection because it provides a balanced assessment without overemphasizing any single area of the vessel while still being cost-effective in terms of required labor and time.