When referring to 4" diameter ducts, the numbers 6", 8", and 10" typically indicate what measurement?

The numbers 6", 8", and 10" in the context of ductwork typically refer to the diameter of the ducts. When discussing ducts, the measurements given often indicate the circular opening or cross-section, which is typically expressed in diameter. Understanding that duct sizing corresponds directly to the diameter is crucial for proper airflow calculations and duct system design.

In the case of a 4" diameter duct, referring to additional sizes such as 6", 8", and 10" indicates increasing diameters of other duct components. This helps HVAC professionals determine the appropriate size for connections, transitions, and fittings in a duct system, ensuring that air distribution meets design requirements.

Specifically, options that reference length or width do not align with standard duct measurements, as ducts are primarily classified by their outer diameter for functionality and compatibility within a system. Consequently, diameter remains the key measurement for identifying and working with different duct sizes in HVAC applications.