If a vessel has an internal refractory lining, what can be inferred about checking the condition of the base metal?

When a vessel has an internal refractory lining, it is crucial to assess the condition of the base metal beneath that lining. The correct choice indicates that if the refractory lining is in good condition, it can serve as an effective barrier for protecting the base metal from the harsh conditions it may face. However, this does not negate the necessity to evaluate the underlying base metal.

A good condition of the refractory lining suggests that it has been functioning as intended, which often correlates with a lower likelihood of damage or degradation to the base metal. Maintenance protocols often allow for some methods of assessing the base metal integrity without needing to remove the refractory. For example, techniques such as thermal imaging or ultrasonic testing can sometimes be employed from outside the refractory if conditions permit.

Removing the refractory completely to inspect the base metal would be costly and may not be necessary if the lining is intact. Thus, it is appropriate to conclude that the condition of the base metal can be adequately inferred and checked if the refractory lining itself shows no signs of wear or failure. Therefore, the option indicating that the base metal condition can be checked if the lining is in good condition reflects the practical approach to maintenance of pressure vessels with refractory linings.