Is it possible to monitor the impedance of the insulation layer as soon as moisture penetrates its outer surface, or to monitor the corrosion rate on the surface of the insulation layer?

Most engineers in the process industries understand the principles of Corrosion Under Insulation (CUI). Corrosion begins when water penetrates the insulation system and reaches the pipe surface. However, in practical applications, the issue is rarely that simple.
Moisture can enter the insulation layer through damaged cladding, aged seals, wind-driven rain, or even via condensation when the temperature inside the insulation system drops below the dew point. Once inside, moisture tends to remain trapped against the steel surface for extended periods.
How insulation systems affect CUI
The choice of insulation material is usually driven primarily by thermal performance and personnel safety considerations. However, the design and material properties of the insulation system also influence how moisture behaves once it enters the system, including:
•    Moisture ingress—Insulation systems are rarely perfectly sealed. Exposure to the elements, mechanical damage, and aging outer jacketing systems can all allow moisture to penetrate the insulation layer.
•    Moisture retention and evaporation—Once water enters the system, the internal structure of the insulation material determines whether the moisture drains away, evaporates, or remains trapped against the pipe surface.
•    Thermal cycling—Fluctuations in process temperatures create alternating wet and dry conditions, which accelerate corrosion reactions.
•    Material chemistry—Some insulation technologies incorporate anti-corrosion components designed to slow the onset of corrosion on the metal surface.

How to drain moisture from insulation: North American practices use PPS drainage plugs.

The problem is that all these corrosion processes occur out of sight. By the time corrosion is detected during inspections or plant maintenance, significant wall-thickness loss may have already occurred. Consequently, many operators are shifting their focus upstream; rather than concentrating solely on early detection, they are working to reduce the likelihood of corrosion occurring at the source.
Personally, I feel that by the time wall-thickness loss is detected via ultrasonic or neutron testing, the damage is often already severe. Is it possible to monitor insulation impedance as soon as moisture reaches the outer layer of the insulation, or to monitor corrosion rates at the insulation surface?
For moisture detection, we use impedance-based monitoring on the outer surface of the insulation to detect moisture immediately. Regarding drainage, we employ standard North American drainage plugs combined with "leak-sniffing" glass vials to detect leaks.
For corrosion monitoring, we use integrated ER (Electrical Resistance) corrosion rate sensors installed beneath the insulation layer... Leakage protection and monitoring for Corrosion Under Insulation (CUI) is a major challenge. For leak monitoring, we adhere to European cabling standards, while for corrosion monitoring, we employ European ER technology. Technology requires promotion and continuous improvement—rather than the indiscriminate use of substandard materials, non-compliant installation practices, and a reliance on winning bids solely through low pricing.