Because of rigid polyurethane insulation foam insulation layer tightly bonded to the steel sheath heating pipe insulation, cut off from air and water infiltration, can play a good anti-corrosion effect. While its foam cells are closed air-conditioning pipe insulation, water absorption is very small. High density polyethylene shell, fiberglass shell have good anti-corrosion, insulation and mechanical properties. Therefore, it works hard to be outside steel jacket of air and water erosion. As long as internal quality pipeline deal, according to foreign information on the life of steam pipe insulation, heat prefabricated buried pipe insulation pipe insulation up to 50 years, than the traditional trench laying, overhead laying high life 3--4 times. Prefabricated buried pipe insulation manufacturers to produce such products with good to resist corrosion and insulation performance. Since the insulation layer such products can more closely fit the outer surface of the pipe, so you can avoid some of the water into a certain extent, so as to effectively prevent corrosion due to excessive moisture from entering the tube body to aging. Furthermore, since this material is more tightly wrapped in the pipeline, so that will also play a role in high-quality insulation.