How is the thickness of the galvanized sheet when the ventilation duct is machined? When the length or diameter is the same, it is the same as the thickness of the rectangular duct of the circular duct. This is a problem that is often encountered during the ventilation process , Select the appropriate thickness of the galvanized sheet, to ensure compliance with national standards, while easy construction, cost savings, safe and efficient, which is to choose the appropriate thickness of galvanized sheet to follow a few principles.