What is the result of multiplying free area in square inches by velocity in feet per minute?

Multiplying the free area in square inches by the velocity in feet per minute yields a result that represents the airflow rate, often measured in cubic feet per minute (CFM). This calculation is based on the principle that airflow can be described as the product of the area through which air is moving and the speed at which it is moving. In essence, by determining how much area is available for air to flow through and how fast that air is moving, you can quantify the total volume of air that passes through that area over a certain period.

This relationship is fundamental in HVAC and fluid dynamics, as it allows professionals to size ducts and systems appropriately to ensure adequate airflow in buildings and other environments. Therefore, the correct understanding of this multiplication operation leads to determining the airflow rate in CFM, making it an essential concept in system performance certification.