What is the standard measurement for the throat of a rectangular duct elbow at a specified angle?

The standard measurement for the throat of a rectangular duct elbow at a specified angle is the radius of the elbow. This measurement is crucial because it determines how the airflow will transition through the elbow and into the ductwork. The radius is essential for ensuring that the design minimizes turbulence and pressure loss, both of which can significantly affect the efficiency of the ventilation system.

In practical applications, having the correct radius allows for smoother airflow transitions, which helps maintain optimal performance within the duct system. It's important to note that the radius should be consistent with industry standards to facilitate compatibility with other duct components.

Other options, such as the depth, width, or length, refer to different dimensions of the duct design and do not specifically define the curvature that affects airflow dynamics inside the elbow. Thus, the radius is the key measurement that impacts the functionality of the rectangular duct elbow.