How frequently should refractory linings be inspected for wear and damage?

The correct choice emphasizes a flexible approach to inspecting refractory linings based on operational guidelines. This flexibility is crucial because the frequency of inspections can depend on various factors, including the operating conditions, the type of material used for the refractory lining, and the specific service application of the pressure vessel.

Regular inspections as suggested in operational guidelines ensure that potential wear and damage are detected early, which is vital to maintain the integrity and safety of the pressure vessel. It allows for adjustments to inspection frequency based on real-time data, operating history, and any observed issues. Thus, establishments can ensure that they are meeting safety standards effectively while also maintaining operational efficiency.

In contrast, the other options suggest rigid inspection schedules that may not accurately reflect the actual wear and tear on the lining. Monthly inspections could be excessive and impractical for many operations, while annual inspections may not provide sufficient oversight in environments with rapidly changing conditions. Relying solely on inspections during significant changes could leave operators vulnerable to unnoticed deterioration between these events, potentially compromising safety and performance.