Polyphenylene insulation board and polyurethane insulation board have very low thermal conductivity and low price. They are the most cost-effective and widely used external wall insulation materials. Their combustibility and aging characteristics restrict the development of energy-saving technology in China. In developed countries, the practice of sandwiching the thermal insulation material in the middle of the concrete is adopted, which not only ensures the thermal insulation performance of the external wall, but also solves the fireproof performance of the thermal insulation board, and at the same time achieves the same life span of the thermal insulation layer and the external wall; Insulation facades (also known as "TM exterior walls") will become the mainstream technology for PC buildings, fiber-composite connectors is factor product, have been use for PC project in the world.
