What Is a Ducting Flange?
A ducting flange is a type of flange designed for use with air ducts in ventilation, heating, and air conditioning (HVAC) systems. These flanges facilitate the connection of duct sections to each other or HVAC equipment, ensuring a secure and leak-proof assembly.
Uses of Ducting Flanges
Ducting flanges are integral to the construction and maintenance of HVAC systems within residential, commercial, and industrial buildings, as well as in applications requiring precise control of airflow, such as in thermal power plants. Their modular design allows for easy assembly, disassembly, and access for cleaning and inspection, making them preferable to permanent welds or direct connections.
Principle of Ducting Flanges
Similar to pipe flanges, ducting flanges create a tight seal between joined duct sections using gaskets. This sealing mechanism prevents air leakage and ensures the efficient operation of the HVAC system. Proper installation involves the use of bolts and nuts to compress the gasket between the flanges, achieving a secure seal.
Types of Ducting Flange Joints
Ducting flanges for rectangular and circular ducts vary in their design and installation methods:
- Angle Flange Method: Steel or stainless steel flanges are attached to the duct ends and bolted together, providing a robust joint.
- Co-plated Flange Method: The duct end is bent to form a flange, which is then secured using clips, offering a balance between installation speed and cost.
- Slide-on Flange Method: A separately formed flange is slid onto the duct end and secured with clamps, allowing for quick and cost-effective assembly.
For circular ducts, metal ducts may use flange fittings similar to the angle flange method, while resin ducts, such as those made from rigid vinyl chloride, employ resin angle flanges welded to the duct ends.
Standards and Specifications
Ducting flanges are manufactured and installed according to specific standards that define their dimensions, materials, and performance criteria. For instance, JIS A4009 outlines the components and joint structures for air ducts used in air conditioning and ventilation equipment.