Material grade is generally divided by use:

1, air duct for air conditioning system: galvanized sheet, stainless steel; (FRP and composite materials that may be polluted by dust sources in use are forbidden)

2, the central air conditioning system with duct: galvanized sheet, color steel insulation board; (FRP and composite materials can be used)

3, environmental control system with air duct: galvanized sheet, stainless steel; (Plastic, FRP, composite materials can be used)

4, industrial ventilation system with air duct: steel plate, galvanized sheet; (Plastic, FRP, composite materials can be used)

Note: FRP air duct can be divided into organic and inorganic. According to the design specifications, organic materials are prohibited if there are fire protection requirements.

5. Air ducts for special use occasions: mine coated duct, mine plastic ventilation duct; (Requirements for flame retardant and antistatic mine safety characteristics)