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: The force required to move air through various components, such as filters, dampers and diffusers. This represents a resistance to air flow.
Static pressure is the outward force of the air in the ducts and represents a waste or loss of available pressure. Anything that adds air resistance, such as corners in ducting and filters will increase the static pressure.
: The force exerted by a moving air stream. It is produced in the direction of the moving air. This represents the useful value of pressure that moves air through the ductwork.
: The sum of static and velocity pressure inside an HVAC system; the total opposition to airflow in a ducting system.
An will have a maximum value of pressure that it can produce. If is too high relative to , the fan will be unable to circulate air throughout the ducting system. Most air handling units will have a maximum pressure rating that they are designed to deliver.
In testing HVAC systems, it is sometimes necessary to test the pressure at various places. Direct measurements can give values for or pressure, from which the pressure can then be derived.
The force resisting the movement of air.
The force exerted by a moving air stream, in the direction of the moving air.
The sum of static and velocity pressure that must be overcome by an air handling unit.
The component of an HVAC system which drives air through the building.