When calculating CFM in a duct, what unit is air velocity measured in?

In HVAC applications, when calculating CFM (Cubic Feet per Minute), air velocity is measured in Feet per Minute (FPM). This unit is crucial because CFM represents the volume of air being moved through the duct system, and understanding air velocity (the speed at which air is traveling) is essential to determine the airflow rate.

Feet per Minute is a standard unit used in the industry that directly relates to the performance of HVAC systems. It indicates how quickly air is moving, which helps in assessing the efficiency and effectiveness of the ductwork design. Using this measurement allows technicians to calculate the volume of air displaced over time, which is pivotal for achieving desired temperature control and ventilation in a space.

Other units such as Miles per Hour and Inches per Second, while they measure speed, are not typically used in HVAC contexts for air velocity calculations. Pascals, on the other hand, measure pressure rather than velocity, making it unrelated to the calculation of CFM in terms of air speed. Understanding why Feet per Minute is the correct unit underscores its industry relevance and practical application in HVAC calculations.