If a field inspection reveals wetting marks and there is no instrument available to measure surface leakage, what is the recommended action?

• A. Cleaning or replacement.
• B. Ignore the wetting marks if the system seems stable.
• C. Schedule the next inspection in six months.
• D. Increase the inspection interval and wait.

Answer: (A)

Wetting marks show that moisture and contaminants have created a leakage path on the surface. With no instrument to measure surface leakage, you can’t reliably judge its severity, so you need to take corrective action now rather than postpone.

Cleaning the surface removes the moisture and contaminants that promote leakage and can restore the insulation’s performance. If cleaning isn’t enough—if the surface is degraded or the marks persist—you should replace the affected part to prevent future problems.

Delaying maintenance, ignoring the marks, or simply waiting for a later inspection risks an insulation fault or equipment failure. Therefore, cleaning or replacing the component is the appropriate action.