What is the minimum film clarity required for horizontal welds according to the standards?

• A. 1 inch of vertical and horizontal weld
• B. 2 inches of vertical weld and 3 inches of horizontal weld
• C. 3 inches of horizontal weld and 2 inches of vertical weld
• D. 2 inches of horizontal and vertical weld

Answer: (D)

The minimum film clarity required for horizontal welds, according to the standards, is 2 inches for both horizontal and vertical welds. This clarity ensures that the welds are inspected thoroughly to guarantee their integrity and quality. The specified dimensions allow for an adequate inspection area, enabling inspectors to evaluate the welds for any potential defects or irregularities that could affect the structural integrity of the tank.

In the context of API 650, proper inspection of welds is critical to ensure that the storage tanks are safe and durable for storing oil and other liquids. Adequate film clarity helps detect issues like porosity, undercutting, or overlap, which could compromise the weld's strength.

While other choices specify varying dimensions, they do not meet the standard requirements for clarity necessary to perform a comprehensive evaluation of the welds. Thus, the choice indicating 2 inches for both horizontal and vertical welds matches the guidelines set forth in API 650, emphasizing the importance of maintaining stringent quality control measures in welded tank construction.