What label is associated with rectangular ducts according to this code?

In the context of the North Carolina Mechanical Code, rectangular ducts are specifically identified with a "rectangular label." This labeling is crucial for clear identification and proper installation within a ventilation or HVAC system. It ensures that installers, inspectors, and maintenance personnel can easily recognize the type of ductwork being used, which aids in ensuring compliance with safety and performance standards set forth by the code. Proper labeling helps avoid confusion between different duct shapes, such as round or square, which have different installation practices and airflow characteristics. Therefore, the designation of the label as "rectangular" accurately reflects the shape of the duct and aligns with the standardized terminology used in the industry to maintain consistency and clarity in mechanical installations.