A duct tee connects a branch to a main run, but its geometry also influences pressure loss and flow distribution. Specify it with a sketch showing connection sizes, airflow direction and joining method. A single diameter cannot identify a three-port fitting completely.
Name every connection
Label the two main-run ends and the branch. State whether the tee is equal or reducing, and distinguish nominal duct diameter from the fitting's external envelope. Include insertion lengths, flange or clamp space and insulation where relevant to installation clearance.
Lindab's tee data lists main and branch dimensions separately, alongside fitting lengths. These are different dimensions and should remain separate on a purchasing drawing.
Show whether air divides or combines
Supply branches and extract junctions can use the same-looking fitting with different flow conditions. The split or combination, relative flows and branch shape affect resistance. The system designer should compare the chosen junction using appropriate fitting data and provide balancing provisions where required.
A tee does not independently guarantee equal airflow to two outlets. Duct lengths, downstream equipment and terminal resistance also influence the distribution. If a branch underperforms, check the complete path before assuming that a larger fan is the only solution.
Match the joint and service conditions
Spigot, flange and rolled-edge clamp systems are different interfaces. Nordfab's tee branch illustrates a clamp-based arrangement. A nominal diameter match does not guarantee that fittings from different joining systems will connect correctly.
Specify material, conveyed air or contaminant, pressure conditions and required sealing. Provide independent support and space for assembly or cleaning. Dust or process extraction may require additional engineering for transport velocity, accumulation and hazardous-material risks; a general ventilation tee is not automatically suitable for every process stream.
For duct tees, send shengtongjh a labelled sketch with the three connections, airflow and joint type. That small drawing can prevent diameter, orientation and installation mismatches.