Rigid polyurethane foam insulation and external insulation with high-density polyethylene outer sheath (jacket layer) forming a plumbing pipe insulation production process, we call this "one-step", Mr. outputs high density polyethylene outer sheath insulation pipe, then the gap between the polyethylene outer sheath and steel production process re-casting of polyurethane rigid foam insulation is that we often say "two-step" process with a production of prefabricated panels, which prefabricated buried texture is very solid insulation electric heating pipe insulation, can withstand high mechanical strength to live, even the kinds of products can play a role in load-bearing buried pipe insulation, visible strength of this material. When the amount of insulation in the implementation of the measures, a reasonable choice of insulation materials, and be able to adapt the structure of the insulation is necessary, we can not leave a gap or some other situation that may exist heat.