Why is it necessary to ensure proper corrosion protection of the metal surface and to apply a moisture-proof layer for insulation when dealing with equipment and pipelines?
Thread Content
Why is it necessary to ensure proper corrosion protection of the metal surface and to apply a moisture-proof layer for insulation when dealing with equipment and pipelines?
Polyurethane foam plastic is generally used for insulation. It is primarily an organosynthetic material that is foamed on-site using polyethers and polyisocyanate esters along with various additives and flame retardants. Since the insulation material is dry when in contact with the metal surface during initial use, it does not corrode the metal surface. However, over time, due to temperature differences, moisture inevitably accumulates between the insulation layer and the metal surface. Due to the presence of water in the interface layer between polyurethane and metal, the polyurethane material releases substances in the presence of this water, resulting in acidic water with a pH of 3-5. At the same time, it still contains harmful substances such as certain chlorides, potassium oxide, and sodium oxide in water
Regarding the moisture prevention issue outside the insulation layer, this is due to the temperature difference effects that occur during the operation of the insulation equipment and pipes. In other words, condensation water often forms on the outer surface of the insulation layer, and moisture also has a corrosive effect on the protective layer used. Therefore, it is common practice to apply 3–5 millimeters of asphalt mastic on the surface of the insulation layer as a moisture barrier. It prevents condensation water from accumulating on the insulation material, thereby avoiding the formation of unnecessary acidic water. First, it prevents a reduction in the effectiveness of the insulation layer ； Secondly, it prevents the protective layer from being corroded by acidic water.
We have already discussed in detail why it is necessary to provide corrosion protection for the metal surfaces and moisture-proof layers for insulation when dealing with equipment and pipelines. Therefore, it is essential to pay attention to such details at work and ensure proper corrosion control of the equipment.