Foam glass is a new type of inorganic thermal insulation material with a uniform independent closed cell structure, which is made of glass as the main raw material, mixed with an appropriate amount of foaming agent, foamed through a high-temperature tunnel kiln, and then processed by annealing and cooling. It completely retains the chemical stability of inorganic glass, with low density, low thermal conductivity, no moisture permeability, no water absorption, no burning, no mildew, no rat bite, high mechanical strength, easy processing and resistance to hydrogen fluoride removal. All chemical attack properties except acid.