Final answer:
The inspection frequency for pressure tanks is commonly about every 10 years as per API Standard 510, but may vary based on several factors and local regulations.
Step-by-step explanation:
The frequency at which the inside of pressure tanks should be inspected varies based on regulations that are often industry-specific and may also depend on the country or region. However, as a general guideline, the American Petroleum Institute's API Standard 510 recommends that pressure vessels undergo thorough internal inspections approximately every 10 years.
This time frame can be adjusted based on factors such as the tank's age, usage conditions, the materials stored within, previous inspection results, and local regulations. To ensure safety and compliance, it's crucial for operators to follow the specific inspection intervals established in the relevant codes and standards for their industry and location.