How Corrosion Under Insulation Could Be Destroying Your Pipes

Thermal insulation is used to reduce heat loss from equipment operating at elevated temperatures. There are three reasons for this:

• To keep a product at a desired temperature
• To reduce energy costs
• For personnel safety

Protected equipment is frequently exposed to adverse weather, so insulation must be waterproof.

Corrosion Under Insulation

Measures taken to keep moisture out of mechanical insulation products like fiber glass and rockwool are only partially successful, in part due to continual movement caused by expansion and contraction of the equipment.

In exposed locations where humidity is high, it’s almost inevitable that moisture will seep through to the protected surface and, once there, it rarely evaporates, especially when the equipment being protected is exposed to adverse weather.

These conditions are ideal for corrosion under insulation (CUI) to take place. Even where an anti-corrosion paint layer has been applied, it is not long before localized pitting corrosion can start.

Consequences of Corrosion Under Insulation

Pitting corrosion is insidious, difficult to detect, and usually continues until the vessel being protected is holed. Pitting corrosion happens quickly and serious damage can occur within a relatively short time.

A National Board of Boiler and Pressure Vessel Inspectors article on preventing corrosion under insulation points out that pitting corrosion leads to significant losses due to product spillage and fires.

Methods of Preventing Corrosion under Insulation

Traditional methods of preventing CUI focus on regular maintenance of the outer skin of the mechanical insulation, supplemented by regular physical inspection.

Source:http://www.ncmiinc.com/corrosion-under-insulation