Pipework and vessels, which operate at high or very low temperatures, are predominantly covered by insulation to prevent heat and energy loss and for health and safety issues. The problem of Corrosion Under Insulation (CUI) can occur in both carbon steel and stainless steel.

This is mainly as a result of water ingress into thermal insulation on pipework and vessels leading to rapid corrosion.

Some of the causes for the presence of water may be:

• Water trapped in the insulation during construction, e.g. storage in places where moisture exists, application carried out during poor weather.
• Joints in traditional claddings as they can form an inherent design weakness
• Mechanical damage of traditional cladding
• Spillage of liquid in low lying areas
• Condensation if there are cyclic temperature fluctuations

Other factors that affect and accelerate the onset of CUI are ions such as chlorides and sulfides. Under certain circumstances these ions can accelerate the corrosion and can lead to different forms of corrosion such as pitting corrosion on carbon steel or stress corrosion cracking on stainless steel.

Temperature fluctuations also play a major part in the severity of the corrosion taking place. In general all chemical reactions (of which corrosion is a form) are accelerated by increases in temperature. 

The worst form of attack is a combination of cyclic temperature and the presence of ions as this can create a concentration mechanism whereby the repeated condensing and evaporation of liquid deposits increases more and more the concentration of the ion species at the point of corrosion, massively accelerating the rate of corrosion.

These forms of corrosion are of particular concern as they are often unforeseen and hidden from view until premature and potentially catastrophic equipment failure occurs, something we call detonation.

So how can Belzona help? What makes us different?

Cost Effectiveness

• One of the key features of Belzona products for CUI is their heat activated curing properties, which allows them to be applied directly to hot surfaces, minimizing downtime.
• Belzona products exhibit high adhesion and bond to manually prepared surfaces, overcoming the traditional challenges of surface preparations during the application.

Ease of Use and Safety

• Belzona products are solvent free and cold applied, eliminating hot work, and have been designed to be easy to use and as safe as possible.

• This solution differs from the thermo-spray systems as these require being heated in order to work, entailing a need for special safety permits; for instance: aluminium linings applied by thermo-spray (TSA). Belzona offers a solution which does not require preheating and therefore avoids the associated hazards and problems.

Durability

• Belzona products are resistant to a wide range of chemicals and heat and in addition provide excellent corrosion resistance. As well Belzona can offer a long-lasting weather and water resistant insulation cover, preventing corrosion occuring below the insulation.

Why does it work?

The porosity of the steel increases with the heat and enables an excellent bond to be achieved. Belzona has therefore developed heat activated products which become less viscous with temperature and penetrate hot surfaces. This leads to products wetting out the surface and achieving better bonding performance even to manually prepared surfaces.

Please let us know how we can help you repair, protect and improve your component equipment.

Stephanie Rumford
srumford@rumfordgroup.com
937-435-4650
RumfordGroup.com