Several years of practical results have thoroughly demonstrated that the construction method of polyurethane insulated buried pipes, compared to the traditional trench and overhead methods, offers numerous advantages. The buried insulation pipes are formed by a tightly integrated combination of a steel pipe for conveying medium, a high-density polyethylene jacket, and a rigid polyurethane foam insulation layer between the steel pipe and jacket. The预制buried insulation pipes have a thermal conductivity coefficient that is much lower than that of other previously commonly used pipe insulation materials, improving the insulation effect by 4 to 9 times. Moreover, their water absorption rate is very low, approximately 0.2 kg/m2. The low water absorption rate is due to the closed-cell rate of the polyurethane foam being around 92%. The low thermal conductivity and low water absorption, along with the insulation layer and the exterior waterproof high-density polyethylene or glass fiber jacket, alter the traditional trench installation of heating pipelines, which was akin to "wearing a wet sweater." This significantly reduces the overall thermal loss of the heating pipelines, with a heat network loss of 2%, which is less than the international standard requirement of 10%.