Definition - What does Thermal Insulation mean?
Thermal insulation is the process of insulating material from transferring heat between the materials that are in thermal contact. Thermal insulation is measured by its thermal conductivity. Low thermal-conductive materials are used for thermal insulation. Besides thermal conductivity, density and heat capacity are also important properties of insulating materials.
Corrosion under insulation is prevalent in petrochemicals and other industries where pipes and equipment are insulated from heat. Corrosion normally occurs on the insulation materials underlying piping or equipment. It also affects the insulation of jacket materials.
Corrosionpedia explains Thermal Insulation
Thermal insulation is the process of retarding the flow of heat from transferring between adjacent surfaces. Specially engineered methods or processes, and appropriate object shapes and materials are needed to achieve thermal insulation.
Thermal insulation materials, known as insulators, are installed in commercial buildings to improve the energy consumption of the buildings' cooling and heating systems. They are also installed in industrial systems to control heat gain or heat loss on process piping and equipment, steam and condensate distribution systems, boilers, and other process equipment.
For thermal insulation, the flow of heat through the insulation material needs to be resisted. Therefore, the insulation material working as an insulator should inhibit the flow of heat between the adjacent surfaces of contacting materials by any heat transfer mechanism.
In petrochemical industries, corrosion of steel is caused by the thermal insulation of pipes and other equipment. It is considered severe because it eventually causes plant failure and accidents. Corrosion under thermal insulation is serious and remains hidden under the jacket until it gets aggravated and causes plant shutdown.
The rusting (oxidation) of carbon steel and chloride stress-corrosion cracking are two common types of corrosion that occur under thermal insulation. The presence of water or moisture and chloride ion causes this corrosion. This corrosion can be controlled with an appropriately designed and installed jacket, using a high-quality vapor retarder and quality painting where needed.