When must corrective action be taken if pitting is found on a tank shell?

When must corrective action be taken if pitting is found on a tank shell?

• A. When pits are deeper than 50% of t-min
• B. When remaining thickness is less than 50% t-min
• C. When pits are deeper than 60% of t-min
• D. When remaining thickness is less than 60% t-min

Answer: (B)

Corrective action must be taken when the remaining thickness of the tank shell is less than 50% of the minimum required thickness (t-min). This criterion is critical for ensuring the structural integrity and safety of the tank. When pitting occurs, it diminishes the effective material thickness, potentially leading to failure under pressure or environmental conditions. Monitoring the remaining thickness is essential in evaluating the impact of pitting. If the thickness falls below this threshold, it indicates a significant reduction in the tank's ability to withstand operational demands, thus necessitating corrective measures to prevent leaks, ruptures, or other failures. This practice ensures ongoing compliance with safety standards and protects both the environment and public safety. The other conditions regarding different percentages of t-min emphasize safety but do not trigger immediate corrective action as defined by the criteria related to 50% t-min.

Corrective action must be taken when the remaining thickness of the tank shell is less than 50% of the minimum required thickness (t-min). This criterion is critical for ensuring the structural integrity and safety of the tank. When pitting occurs, it diminishes the effective material thickness, potentially leading to failure under pressure or environmental conditions.

Monitoring the remaining thickness is essential in evaluating the impact of pitting. If the thickness falls below this threshold, it indicates a significant reduction in the tank's ability to withstand operational demands, thus necessitating corrective measures to prevent leaks, ruptures, or other failures. This practice ensures ongoing compliance with safety standards and protects both the environment and public safety.

The other conditions regarding different percentages of t-min emphasize safety but do not trigger immediate corrective action as defined by the criteria related to 50% t-min.