The volume of airflow in a duct is expressed in what unit?

The volume of airflow in a duct is typically expressed in cubic feet per minute (CFM). This is a standard measurement in HVAC and sheet metal work because it provides a convenient way to assess the amount of air moving through a given space within a specified period of time. CFM is widely used in the industry, allowing professionals to determine air distribution, ventilation needs, and system efficiency.

Using CFM helps in sizing ductwork appropriately and ensuring proper airflow rates according to the design and requirements of a space. This measurement allows for effective calculation and adjustment of HVAC systems to achieve desired environmental conditions.

While liters per second, cubic meters per hour, and gallons per minute are valid units in other contexts, they are not as commonly used in the specific field of sheet metal and ductwork design as CFM. As such, they may lead to confusion or errors in systems where air volume calculations are critical.