Definition - What does Insulation mean?
Insulation is a general term used to describe material that creates barriers for transmission of electricity, heat, moisture, shock or sound between insulated surfaces of adjacent bodies. These materials could be insulating heat, cold, electricity, sound or radiation.
Insulation-trapped moisture or water causes corrosion in insulating bodies like insulated pipes in the process industries affected by corrosion under insulation.
Corrosionpedia explains Insulation
Insulation refers to a barrier to the progression or transmission of any forms of energy through the insulated surfaces. It has various applications. They are:
- Building insulation – used in buildings for comfort and energy savings
- Electrical insulation – used to resist electricity and magnetism
- Insulated glass – used for power-saving
- Acoustic insulation – used to reduce the intensity of sound
- Thermal insulation – used to reduce heat transfer
In marine, petrochemical and chemical process industries, corrosion under insulation (CUI) is a major headache for engineer. CUI is a severe form of localized corrosion in insulated carbon and low alloy steel equipment. Under insulation, water is absorbed or collected and leads to corrosion. This corrosion begins when insulated materials are exposed to water and oxygen. CUI is also common in equipment typically operated at high temperatures like refineries.
This type of corrosion can be prevented by using inhibitors and preventing the ingress of water from external sources. The proper selection of insulating materials to prevent corrosion under insulation is also crucial. Finally, the use of protective coating systems is very important. Anti-corrosion and inhibitive coatings also need to be considered for longer protection.