In air conditioning systems, ducts transport conditioned air to various building zones. The predominant shape for air ducts in structures is rectangular. Rectangular ducts are favored due to their ability to fit in confined ceiling areas and their ease of installation along walls and partitions. While round ducts are employed, their use is primarily confined to situations where space is not a constraint and for less extensive applications. Square and elliptical duct shapes are rarely used in practical design. Consequently, rectangular is established as the standard shape for air conditioning ducts.