How must duct connections to flanges of air distribution system equipment be secured?

Duct connections to flanges of air distribution system equipment must be mechanically fastened to ensure a secure and effective seal that prevents air leaks and maintains the efficiency of the HVAC system. Mechanical fastening means using screws, bolts, clamps, or other fastening devices to physically join the ductwork to the equipment flanges. This helps in maintaining the integrity of the air distribution system, reducing operational noise, and ensuring that the system meets the performance standards required by the mechanical code. Proper mechanical attachment is essential for the durability and safety of the installation, particularly in preventing system failure caused by loose connections.