Modified, non-combustible inorganic glass steel ventilation ducts that inorganic materials, cementitious materials, water-repellent material for the binder, fiberglass cloth reinforcing material, together with the toughening agent, enhancer, and anti-agent, through a rigorous modulation procedures, processes and conservation process, the formation of crystalline steel Luo skeleton and void structure of hardened body. It has a lightweight, high strength, corrosion-resistant aging, pollution-free non-toxic, shock absorption silencers, insulation, heat-resistant non-combustible, no distortion, no cracks, does not absorb moisture, do not brine back, volume stability, etc., and long service life. To solve the problem of plexiglass steel duct flammable, metal duct corrosive, noise, and short life. Moreover, the product price lower than the price of plexiglass steel duct. Is the best matching with central air-conditioning equipment. Therefore, its application in various fields of national economy has considerable development potential and market competitiveness, the share of the market is gradually expanding, the best products of the present and future large-scale indoor ventilation. Widely used in metallurgy, mining, textiles, tobacco, military, hotels, shopping malls, theaters, civil air defense projects, underground parking and high-rise building's ventilation and air conditioning engineering. Also be used for the production of the chemical industry and other industrial flue gas emissions chimney, oil and chemical liquids storage and construction projects downspouts. Pipe types: duct structure: monolithic, modular, prefabricated three; duct function: Air Conditioning, air class, the exhaust (smoke) in three; points from the insulation performance: single-wall sandwich of two; installation requirements: concealed, exposed two.