Ducts allow air to travel from HVAC equipment to heat and cool various rooms or offices. The size of the ducts affect the air flow rate and the velocity of the air as it flows through the duct. Therefore, sizing the ducts depends on the air flow and the velocity requirements established by the designers of the building.
Determine the required air flow rate in units of cubic meters per second. Refer to the air flow design specifications or requirements associated with the building.
Determine the required air speed in units of meters per second. Refer to the air flow design specifications or requirements associated with the building.
Calculate the duct size in units of square meters using the formula: area equals quantity divided by velocity. For example, if quantity is 12 cubic meters per second and velocity is 4 meters per second then the equation is: area is equal to 12 divided by 4. Therefore, the duct area is 3 square meters.