Solar hot water system engineering heat collecting system connecting pipe, water tank, water supply pipe should be heat preservation. Materials commonly used are rockwool, polyurethane, rubber foam and other materials, insulation thickness can refer to different forms of installation under the pipe diameter and thermal insulation layer thickness checklist selection. Insulation materials should choose a wide range of sources, low cost, good insulation properties, easy construction, durable materials, the specific selection of the following requirements: 1 insulation material products should be allowed to use the temperature higher than the maximum temperature of the solar system work medium. 2 insulation materials should not be used organic matter, so as to avoid worms, decay, bacteria, the mouse. 3 should adopt hygroscopicity, water storage is weak, no corrosive effect on the wall material; outdoor pipe insulation layer should be protected by waterproofing. 4 insulation materials should be non-flammable and non-flammable materials, should be consistent with GB "architectural design code for fire protection" requirements; electric heater insulation must be non-combustible materials.        Solar water heating system commonly used insulation system consists of anti-corrosion coating (general brush anti-corrosion paint), insulation layer, moisture barrier (including linoleum, oil paper or brush asphalt) and protective layer. General metal protective layer should be 0.3-0.8MM thick galvanized steel or rust-proof aluminum shell, shell joints must overlap to prevent rainwater access; glass cloth protective layer is generally used indoors; asbestos cement surface protection Do not use it outdoors. Haining Xianke New Materials Technology Co., Ltd.