How many random spot checks are required in each vertical weld in the first course?

• A. None
• B. Two
• C. One
• D. Five

Answer: (C)

In the context of API 650, when evaluating the welds in the construction of welded tanks for oil storage, it is important to maintain quality control during the welding process. For the first course of vertical welds, the standard specifies that at least one random spot check must be performed. This ensures that there is a verification of the weld quality early in the construction phase, allowing any potential issues to be identified and addressed promptly.

The reasoning behind instituting at least one random spot check is to uphold the integrity of the structure by confirming that the welding meets required standards and specifications. Regular inspections are a critical aspect of quality assurance in tank construction, reflecting the importance of preventing defects that could lead to structural failure or leaks in storage tanks. Therefore, performing one random spot check in each vertical weld in the first course aligns with the best practices outlined in API 650.