Rectangular Air Ducts: A Comprehensive Analysis of Material Characteristics, Installation Specifications, and Application Scenarios

 

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.

2. Flow Diversion and Sealing Control

When the long - side dimension of a right - angle elbow exceeds 500mm, flow guide vanes need to be installed to reduce airflow resistance. The arc of the flow guide vanes should be consistent with the elbow angle, and the thickness should be no less than twice the thickness of the air duct sheet (at least 60mm). During installation, the edges should be smooth and firmly fixed. The seams of the air duct should be kept tight and flat, the thickness of the interface gasket should be ≥3mm, and the combined angle seam process is often used for corner combinations to ensure overall tightness.

3. Installation Acceptance Standards

During the installation process, the elevation, direction, and consistency with the design drawings should be strictly verified, and it is strictly prohibited to reduce the effective cross - section of the interface. After installation, strength and air - tightness tests should be carried out according to the system category. In high - pressure scenarios such as smoke prevention and exhaust systems, angle steel flange connections must be used and verified through air - tightness tests.

 

III. Application Scenarios and Advantage Comparison

Rectangular air ducts are widely used in civil buildings and low - speed air duct systems, and are particularly suitable for the following scenarios:

- Areas with limited space: They can be flat - designed to fit the building structure, reducing the occupation of ceiling space.

- Multi - direction airflow control: Through flow guide vanes at right - angle turns, the airflow distribution is optimized, and it is easier to achieve precise turning compared to circular air ducts.

- System compatibility: They are convenient to integrate with components such as fire dampers and air outlets, and are suitable for various systems such as air - conditioning, smoke exhaust, and fresh air.

Compared with circular air ducts, rectangular air ducts are slightly inferior in terms of material consumption and airflow resistance, but they are superior in space adaptability and installation convenience. In actual projects, it is recommended to comprehensively select the type according to factors such as the pressure of the transported medium and the space layout. For example, metal rectangular air ducts are preferred for smoke prevention and exhaust systems, while composite material solutions can be considered for conventional air - conditioning systems.

Through scientific material selection, standardized installation processes, and reasonable scenario adaptation, rectangular air ducts can significantly improve the efficiency of the ventilation system and provide reliable guarantee for building environmental control. During the operation and maintenance process, key parts such as flange tightness and the integrity of flow guide vanes should be regularly inspected to ensure the long - term stable operation of the system.