Speciality Phenolic-aluminium foil compound sandwich panel, is a latest kind of light and environment-friendly heat-preserving material. The middle layer of the sandwich panel is phenolic foam, and the outer layers is embossed aluminium foil. As a new building and aeration material with excellent performance, it enjoys fast developing in China these years. Air-ducts made of Phenolic-aluminium foil compound sandwich panel have the following features: 1. light: It weighs only 1.4kg per m2 and can ease the burden of tall buildings. So it is safer. 2. labour-saving: It is easy and efficient to assemble and install with simple tools. The constructing period is much shorter than that of traditional air-ducts. 3.clean & environment-friendly: Corrosion-proof treated aluminium foil will not oxidate and mildew, and the air will not be polluted while pass the ducts. 4. heat-preserving & soundproof: With more than 90% closed hole, it has excellent air tightness.Its Thermal Conductivity is 0.022-0.040 W/m.k, and can work during -140 to 150 degree Celsius. 5.fireproof: The smoke consistency of phenolic foam is less than 3%, and accord with the requirement of environment-protecting and fireproofing. This is the only product whose indexes of fire-fighting is A-level and can bu used in high-building. 6. good-looking and durable:Can be harmoniously blended with surrounding,it is suitable for visible installation. Aluminium foils are treated with advanced anti-corrosive technics, and its lifespan can reach 20 years. Specifications thickness(mm) nominal dimension:20, tolerance±1 Can be adjusted as per requirement. length (mm) nominal dimension: 2000, tolerance±3 nominal dimension: 4000, tolerance±3 Can be adjusted as per requirement. width (mm) nominal dimension:1200, tolerance±2 Can be adjusted as per requirement.