As a core component of building ventilation and air - conditioning systems, rectangular air ducts, with their rectangular cross - sectional design, demonstrate unique advantages in airflow control, space adaptability, etc. This article will systematically elaborate on the technical points and usage values of rectangular air ducts from three dimensions: material selection, installation specifications, and practical applications.
I. Material and Specification Characteristics
Rectangular air ducts are mainly made of metal materials such as galvanized steel sheets, stainless steel sheets, and aluminum sheets. Among them, galvanized steel sheets are the first choice for civil buildings due to their anti - corrosion properties and moderate cost. For special environments (such as high - temperature, high - humidity, or corrosive places), stainless steel sheets and aluminum sheets can provide higher durability. Non - metal materials such as fiberglass and rigid polyvinyl chloride sheets are suitable for specific anti - corrosion scenarios, but their applicable temperature needs to be controlled between - 10°C and 60°C.
The specification design follows the principle of "customization according to needs". Common size combinations include a width of 200 - 1600mm and a height of 120 - 800mm, and the sheet thickness is usually 0.5 - 1.5mm. During design, it should be noted that the height - to - width ratio should preferably be less than 6 and not exceed 10 at most to balance system resistance and space utilization. For example, an air duct with a specification of 800×400mm has an unfolded area of 0.64㎡ per meter, which can meet the transportation requirements of most medium - and low - pressure systems.
II. Standardized Installation Technology
1. Connection and Reinforcement Technology
When a metal air duct is connected to an angle steel flange, if the pipe wall thickness ≤1.5mm, the flanging riveting process is adopted; if it is >1.5mm, full welding or flanging intermittent welding is required. Before flange installation, rust removal treatment should be carried out and anti - rust paint should be applied. Galvanized rivets are selected to ensure corrosion resistance. For rectangular air ducts with a side length exceeding 630mm or pipe sections with a length >1250mm, reinforcement measures such as stiffeners and angle steel fixtures must be taken.