How to Monitor Corrosion Under Insulation (CUI) in an easy and pro-active manner?

Corrosion under insulation (CUI) poses a significant operational loss, safety hazard and economic cost.

Corrosion under insulation (CUI) is invisible to the surface of the insulation. Because of this, it is very difficult for conventional techniques to detect and monitor corrosion under insulation.

The presence of moisture in and under insulation is the root cause of corrosion under insulation (CUI). Corrosion under insulation is a severe form of localized external corrosion that occurs in carbon and low alloy steel equipment that has been insulated. This form of corrosion occurs when water is absorbed by or collected in the insulation. As a result he equipment begins to corrode as it is exposed to water and oxygen.

Depending on the structure and the location of the insulation, CUI can attack the jacketing, insulation hardware or underlying piping equipment. Additionally, when insulation becomes wet or absorbs moisture, its thermal insulating properties are drastically reduced. Because water conducts heat more efficiently than air, an aggressive corrosion cell is created where the trapped heat accelerates the rate of corrosion.

CUI is common in refineries and process plants that typically operate equipment at high temperatures because high temperature will increase the speed of corrosion. But CUI can also occur at low temperature when condensation occurs.

Such challenges may require installation shutdowns or the removal of insulation. These actions are costly, time consuming and sometimes not necessary but “better be safe than sorry”.



isenspro cui corrosion under insulation


When does corrosion under insulation occur?

In order for corrosion under insulation to occur, a number of factors must be present. These are:

  • Water: Must be present and can be introduced during insulation storage or installation; by internal leaks, ineffective waterproofing, or improper maintenance.
  • Chemical content: Acidity is a big component in the development of CUI. If the pH level drops below 4, corrosion increases rapidly. Acidic corrosion is commonly associated with carbon steel. With austenitic stainless steel, the primary chemical concern is free chloride content in combination with mechanical stress.
  • Temperature: Service temperatures between zero to 100 degrees Celsius allow water to exist as a liquid. Corrosion under insulation can occur on cold process lines because condensation can occur. Cooling lines below 15 degrees Celsius often suffer from condensation issues. For hot lines above 50 degrees Celsius, the corrosion rate doubles for every 15 to 20 degrees Celsius in temperature increase.

iSensPro is a unique and innovative 24/7 real-time monitoring system

iSensPro is an innovative and patented sensor system to inspect, detect, predict and mitigate piping maintenance and CUI challenges. The unique measuring feature enables installation of the sensors ON THE OUTSIDE of the cladding. As such the non-destructive and non-intrusive system can easily be retro-fitted on existing installations. The system can of course also be installed from the start on new installations.

The patented iSensPro is a stand-alone system and is easy to install on the outside of the cladding (non-intrusive installation) without the need to remove the existing insulation. The sensors can detect and monitor 24/7 the presence of moisture under the insulation on pipes, tanks, and valves on a real-time basis. At the same time, the sensors also monitor temperature, movement, noise and leaks.

The system continuously 24/7 monitors the presence of moisture without the involvement of trained personnel. So the sensor system frees up valuable ad-hoc inpsection time, and enables your personnel to focus on mitigation tasks where needed.

iSensPro sensors provide time-based data to enable data-based (rather than risk-based) mitigation plans for the management of industrial assets. And this reduces the costs associated with down time, lost productivity, or even total facility shutdown.

isenspro sensor corrosion under insulation leak detection


Predict & Mitigate

Pro-active maintenance in stead of ad-hoc inspection becomes possible thanks to the iSensPro sensor solution. Because the system provides 24/7 time-based data there is no more need for ad-hoc inspection rounds by personnel. Now switch from risk-based to data-based mitigation and resolution plans for the management of industrial assets.

Data > Knowledge > Action

Compared to other technologies, iSensPro is a unique non-destructive inspection system for piping systems. So now ‘data under insulation’ becomes available for pro-active and predictive maintenance. Upgrade the tasks of your team from inspection to mitigation. The ultimate resolution of corrosion under insulation CUI problems now is possible.

No more fire-fighting!

Master the ‘data under insulation’ and drive your maintenance team to work on pro-active value added tasks.



Demo system

Do you want to try out how easy it is to install the unique iSensPro sensor system?

Simply go to our webform and send us the details of your piping installation, so we can evaluate if your application can be monitored 24/7 with the iSensPro CUI sensor solution. Of course all information you share with us will be treated confidential, and if required, protected by NDA.

1/ Send your information

Send us the details about your piping application as outlined in the webform.

  1. Problem you want to solve
    1. Increased safety: Leak Detection 24/7
    2. Increased safety: Monitor Corrosion under insulation
    3. Energy efficiency: Avoid energy loss due to wet insulation
    4. Reduced maintenance: pro-active mitigation only where needed
    5. Increased production time: time based maintenance reduces downtime
  2. Insulation Material
    1. Mineral Wool
    2. PUR
    3. Other
  3. Pipe Material
    1. Carbon Steel
    2. Stainless Steel
    3. Synthetic
  4. Condition
    1. HOT Heat Loss
    2. COLD condensation prevention
    3. SAFETY Personnel Protection

Simply go to our webform and send us the details of your piping installation. Of course, you can also just contact us by mail.

2/ We evaluate

We perform a quick review of your application. If we think iSensPro can solve your application, we will ask you to send us some additional info (technical details, photo’s if possible,…) to help you configure the CUI and leak detection sensors.

3/ We send your demo kit

The Demo kit includes 3 CUI sensors, a gateway and a link to download our iSensPro Cockpit App on your smartphone.

4/ We review together after 3 months

The iSensPro demo unit will monitor humidity and corrosion under insulation 24/7 for a test period of 3 months

Thanks to iSensPro it is easy to monitor corrosion under insulation and the Master Data Under Insulation!

leak detection cui corrosion under insulation