At least how many feet downstream from elbows or constructions in the ductwork should traverses be made?

The requirement to conduct traverses at least 5 feet downstream from elbows or other constructions in ductwork is grounded in the need to achieve accurate and representative measurements of airflow. Ductwork system components, such as elbows and transitions, can cause turbulence and disruption in the airflow pattern. Conducting traverses too close to these features can result in insufficiently stabilized airflow, leading to erroneous data.

In practice, allowing for a distance of 5 feet ensures that the airflow has had enough time and space to re-stabilize after navigating the disturbances caused by the ductwork components. This distance helps in obtaining measurements that are more reflective of the actual conditions within the duct system, leading to better performance assessment and efficiency calculations.

While larger distances may provide further stabilization, the industry standard of 5 feet is generally regarded as sufficient for most applications, aligning with best practices in airflow measurement.